






                    TTHHEE IINNTTEERRCCAALL PPRROOGGRRAAMMMMIINNGG LLAANNGGUUAAGGEE

                             _D_o_n_a_l_d _R_. _W_o_o_d_s
                                   _a_n_d
                              _J_a_m_e_s _M_. _L_y_o_n

























































                                   - 2 -



       _1_.  _I_N_T_R_O_D_U_C_T_I_O_N

       The  names  you  are  about to ignore are true. However, the
       story has been changed significantly. Any resemblance of the
       programming language portrayed  here  to  other  programming
       languages, living or dead, is purely coincidental.

       _1_._1  _O_r_i_g_i_n _a_n_d _P_u_r_p_o_s_e

       The  INTERCAL  programming language was designed the morning
       of May 26, 1972 by Donald R. Woods and  James  M.  Lyon,  at
       Princeton  University.  Exactly  when  in  the  morning will
       become apparent in  the  course  of  this  manual.   It  was
       inspired  by one ambition: to have a compiler language which
       has nothing at all in common with any other major  language.
       By 'major' was meant anything with which the authors were at
       all  familiar,  e.g.,  FORTRAN, BASIC, COBOL, ALGOL, SNOBOL,
       SPITBOL, FOCAL, SOLVE, TEACH, APL, LISP, and PL/I.  For  the
       most  part, INTERCAL has remained true to this goal, sharing
       only the basic elements such as variables, arrays,  and  the
       ability to do I/O, and eschewing all conventional operations
       other than the assignment statement (FORTRAN "=").

       _1_._2  _A_c_r_o_n_y_m

       The  full name of the compiler is "Compiler Language With No
       Pronounceable  Acronym",  which  is,  for  obvious  reasons,
       abbreviated "INTERCAL".

       _1_._3  _A_c_k_n_o_w_l_e_d_g_m_e_n_t_s

       The authors are deeply indebted to Eric M. Van and Daniel J.
       Warmenhoven,  without whose unwitting assistance this manual
       would still have been possible.




























                                   - 3 -



       _2_.  _F_U_N_D_A_M_E_N_T_A_L _C_O_N_C_E_P_T_S

       In this section an attempt is made to describe how  and  why
       INTERCAL  may  be used; i.e., what it is like and what it is
       good for.

       _2_._1  _S_a_m_p_l_e _P_r_o_g_r_a_m

       Shown below is a relatively simple  INTERCAL  program  which
       will read in 32-bit unsigned integers, treat them as signed,
       2's-complement numbers, and print out their absolute values.
       The  program  exits  if  the absolute value is zero. Note in
       particular the inversion routine (statements 6 through  14),
       which  could be greatly simplified if the subroutine library
       (see section ) were used.

       A more detailed analysis of a program is made in section
        of this manual.


               DO (5) NEXT
           (5) DO FORGET #1
               PLEASE WRITE IN :1
               DO .1 <- 'V-":1~'#32768c/#0'"c/#1'~#3
               DO (1) NEXT
               DO :1 <- "'V-":1~'#65535c/#0'"c/#65535'
                       ~'#0c/#65535'"c/"'V-":1~'#0c/#65535'"
                       c/#65535'~'#0c/#65535'"
               DO :2 <- #1
               PLEASE DO (4) NEXT
           (4) DO FORGET #1
               DO .1 <- "V-':1~:2'c/#1"~#3
               DO :1 <- "'V-":1~'#65535c/#0'"c/":2~'#65535
                       c/#0'"'~'#0c/#65535'"c/"'V-":1~'#0
                       c/#65535'"c/":2~'#0c/#65535'"'~'#0c/#65535'"
               DO (1) NEXT
               DO :2 <- ":2~'#0c/#65535'"
                       c/"'":2~'#65535c/#0'"c/#0'~'#32767c/#1'"
               DO (4) NEXT
           (2) DO RESUME .1
           (1) PLEASE DO (2) NEXT
               PLEASE FORGET #1
               DO READ OUT :1
               PLEASE DO .1 <- 'V-"':1~:1'~#1"c/#1'~#3
               DO (3) NEXT
               PLEASE DO (5) NEXT
           (3) DO (2) NEXT
               PLEASE GIVE UP

       _2_._2  _U_s_e_s _f_o_r _I_N_T_E_R_C_A_L

       INTERCAL's main advantage over other  programming  languages
       is  its strict simplicity. It has few capabilities, and thus
       there are few restrictions to be kept in mind. Since  it  is








                                   - 4 -



       an  exceedingly  easy language to learn, one might expect it
       would be a good language for initiating novice  programmers.
       Perhaps  surprising, then, is the fact that it would be more
       likely to initiate a novice into a search for  another  line
       of  work.  As  it  turns out, INTERCAL is more useful (which
       isn't  saying  much)  as   a   challenge   to   professional
       programmers.   Those  who doubt this need only refer back to
       the sample program in section .  This  23-statement  program
       took  somewhere  from 15 to 30 minutes to write, whereas the
       same objectives can be achieved by single-statement programs
       in either SNOBOL;

               PLEASE INPUT POS(0) ('-' ! '')
               + (SPAN('0123456789') $ OUTPUT)
               + *NE(OUTPUT) :S(PLEASE)F(END)

       or APL;

               [1] ->0!=[]<-|[]

       Admittedly, neither  of  these  is  likely  to  appear  more
       intelligible   to   anyone  unfamiliar  with  the  languages
       involved, but they took roughly 60 seconds and  15  seconds,
       respectively,  to  write.  Such is the overwhelming power of
       INTERCAL!

       The other major importance of INTERCAL lies in its seemingly
       inexhaustible capacity for amazing one's fellow programmers,
       confounding programming shop managers, winning friends,  and
       influencing  people. It is a well-known and oft-demonstrated
       fact that a person whose work is incomprehensible is held in
       high esteem. For example, if one  were  to  state  that  the
       simplest  way to store a value of 65536 in a 32-bit INTERCAL
       variable is:

               DO :1 <- #0c/#256

       any sensible programmer would  say  that  that  was  absurd.
       Since  this  is  indeed  the simplest method, the programmer
       would be made to look foolish in  front  of  his  boss,  who
       would  of  course happened to turn up, as bosses are wont to
       do.  The  effect  would  be  no  less  devastating  for  the
       programmer having been correct.



















                                   - 5 -



       _3_.  _D_E_S_C_R_I_P_T_I_O_N

       The  examples of INTERCAL programming which have appeared in
       the preceding sections of this manual have  probably  seemed
       highly  esoteric to the reader unfamiliar with the language.
       With the aim of making them  more  so,  we  present  here  a
       description of INTERCAL.

       _3_._1  _V_a_r_i_a_b_l_e_s

       INTERCAL  allows  only  2  different types of variables, the
       1166--bbiitt  iinntteeggeerr  and  the   3322--bbiitt   iinntteeggeerr..    These   are
       represented  by  a  spot  (.) or two-spot (:), respectively,
       followed by any  number  between  1  and  65535,  inclusive.
       These  variables may contain only non-negative numbers; thus
       they have the respective ranges of values: 0 to 65535 and  0
       to   4294967295.  Note:  .123  and  :123  are  two  distinct
       variables. On the other hand, .1 and  .0001  are  identical.
       Furthermore, the latter may _n_o_t be written as 1E-3.

       _3_._2  _C_o_n_s_t_a_n_t_s

       CCoonnssttaannttss  are  16-bit  values  only and may range from 0 to
       65535. They are prefixed by a mesh (#).  Caution!  Under  no
       circumstances confuse the mesh with the interleave operator,
       except under confusing circumstances!

       _3_._3  _A_r_r_a_y_s

       AArrrraayyss are represented by a tail (,) for 16-bit values, or a
       hybrid (;) for 32-bit values, followed by a number between 1
       and  65535,  inclusive.  The  number is suffixed by the word
       SUB, followed by the  subscripts,  separated  optionally  by
       spaces.  Subscripts  may be any expressions, including those
       involving subscripted variables. This occasionally leads  to
       ambiguous  constructions, which are resolved as discussed in
       section .  Definition of array dimensions will be  discussed
       later  in greater detail, since discussing it in less detail
       would be difficult. As before, ,123 and ;123  are  distinct.
       In  summary,  .123,  :123,  #123,  ,123,  and  ;123  are all
       distinct.

       _3_._4  _O_p_e_r_a_t_o_r_s

       INTERCAL recognizes 5 operators -- 2 binary and 3 unary [1].
       Please be kind to  our  operators:  they  may  not  be  very
       intelligent,  but  they're all we've got.  In a sense, all 5
       operators are binary, as they are all bit-oriented,  but  it
       is not our purpose here to quibble about bits of trivia.

       _3_._4_._1  _B_i_n_a_r_y _O_p_e_r_a_t_o_r_s

       The binary operators are iinntteerrlleeaavvee (also called mmiinnggllee) and
       sseelleecctt,  which are represented by a change (c/) and a sqiggle








                                   - 6 -



       [sic] (~), respectively.

       The interleave operator takes two 16-bit values and produces
       a 32-bit result by alternating the  bits  of  the  operands.
       Thus,  #65535c/#0  has the 32-bit binary form 101010....10 or
       2863311530 decimal, while #0c/#65535 =  0101....01  binary  =
       1431655765 decimal, and #255c/#255 is equivalent to #65535.

       The  select  operator takes from the first operand whichever
       bits correspond to 1's in  the  second  operand,  and  packs
       these  bits  to  the right in the result.  Both operands are
       automatically padded on the  left  with  zeros  to  32  bits
       before  the selection takes place, so the variable types are
       unrestricted.  If more than 16 bits are selected, the result
       is a 32-bit value, otherwise  it  is  a  16-bit  value.  For
       example,  #179~#201 (binary value 10110011~11001001) selects
       from the first argument the 8th, 7th, 4th, and 1st from last
       bits, namely, 1001, which = 9. But  #201~#179  selects  from
       binary  11001001  the  8th, 6th, 5th, 2nd, and 1st from last
       bits, giving 10001 = 17. #179~#179 has the value  31,  while
       #201~#201 has the value 15.

       Perhaps  a simpler way of understanding the operation of the
       select operator would be to examine  the  logic  diagram  in
       Figure 1, which performs the select operation upon two 8-bit
       values,  A  and  B.  The  gates  used are Warmenhovian logic
       gates, which means the outputs have  four  possible  values:
       low,  high, undefined (value of an uninitialized flip-flop),
       and oscillating (output of a NOR gate with one input low and
       the other input connected to the output). These  values  are
       represented symbolically by '0', '1', '?', and 'O|'.  Note in
       particular  that, while NOT-0 is 1 and NOT-1 is 0 as in two-
       valued logic, NOT-? is ? and NOT-O| is O|.  The  functions  of
       the various gates are listed in Table 1.

       [Warning:  The following picture will be garbled or missing.
       Get a better output device.]

























                                   - 7 -



        --+-+----     --+----  +--+----   --+----  +--+----   +-+
      A1   | | 1  +-+--+-+ 2  +-++-+ 3  ++-+-+ 3  ++|--+ 1  +--| |
      B --+++    | |--+-+    | || |    ||||++    |||| |    |  | |  TO
      1   +++------++-+-+------+|-+---  +++++-----++|-+---    | +--NEW
           +-------++-+---------+-------+++++-----+ |         | | YORK
          +-+------++-+-+-----+ | +---- ||| +-----+ | +----   | |  TO
      A2 --+-+    | || +-+    || --+    |+++-+    |+-+-+    |  | +--NEW
        --+-+ 1  +-++-+-+ 2  +++--+ 7  +-++-+ 3  +--+-+ 2  +--| | YOTROK
      B2   |-+---   |||+-+---  || -+---   |+-+------++-+-------| +--NEW
          +--------+++-+------++---------+--------+|+---------| | YORK
          +-+------+++-++-----++--+-----+| ++-----++--+-----+ | |  TO
      A --+-+    | +++-++    |++--+    |++-++    ||+--+    || |B +--NEW
      3     | 1  +-+++-+| 2  +-++-+ 3  +-++++ 3  ++++-+ 3  ++-| | YORK
      B3 --+-+---  ||||+++---  |||-+---  ++|++---  ||+++---  | | |  TO
          +-------++++++------+++-------++++------++++------+-|U +--NEW
          +-+-----+++-+++-----+++-+-----+++||     ++++|     | | | YORK
      A --+-+----|||| ||+----||++-+----||++++----|+++++----|| |S |  TO
      4     | 1  +++++|++ 2  ++++-+ 7  ++++++ 3  ++++-+ 4  ++-| +--NEW
      B --+-+---  ||||+-+---  ||+-+---  |||++--- ++--++---  | | | YOTROK
      4   |       |||+++      ++--+ +---++++++++++|+-+------+ | +--NEW
          +-------+++-++-------++++-+--+||+++++++-++++--+     | | YORK
        --+-+-----+++-+++-----+++++-+--+++-++++++ +++++-+--   |L |  TO
      A5     | 1  ++++++++ 2  ++++++ 3  +++ ++ 3  +-++++ 5  +--| +--NEW
      B --+-+    |||+++++    |  |||    ||| ||    |++++|    |  | | YORK
      5   |-+---  |||||++-------|++----+|+--+-----+++++-------|I |  TO
          +-------+++++--------++------++++ +---  |+++        | +--NEW
          +-+-----+++++-+-----+|| +----++++++-----+|||+----   |N | YORK
      A6 --+-+    |||-++++    |+++-+    |+++++    | ++++    |  | |  TO
        --+-+ 1  +++-++++ 2  ++++-+ 3  +-++++ 4  ++++++ 4  +--| +--NEW
      B6   |-+---  +++++++---  +++-+-----+||++-----+++++-------|E | YORK
          +--------++++--------++------+|||       ++-+        | +--TO
          +-+------++++-+-----+|| +----++++++---- ||  +----   | | NEW
      A --+-+    | -+++-+    |+++-+    |+++++    ||+--+    |  | | YOTROK
      7     | 1  +--+|+-+ 2  +-++-+ 3  ++|+++ 4  ++-+-+ 5  +--| +--NEW
      B7 --+-+---   ||++-+---   ||++---  || ++---  --+++---    | | YORK
          +----+---++++--------+++------++ +------+-++------+-| |  TO
          +-+--+---++++-+-------+||     |  ||     |  ||     | | +--NEW
      A --+-+----| |+++-+----|+-+++----|+--++----||+--+----|| | | YORK
      8     | 1  +-+ |+-+ 2  ++ +++ 4  ++ +++ 3  ++++-+ 5  ++-|8 |  TO
      B --+-+---     +--+---  |  ++---  | |++---  | |-+---  | | +--NEW
      8   +----------------+  ++-+      +-++---+ ++-+------+| | | YORK
                           +--+++--------+||   +-++++------++-| |  TO
            +----  +-+--+-----+++-+----  ++++----+|++-+----++-| +--NEW
            | 6  +-+ +--+ 2  ++-+-+ 7  +-++-+ 3  +++|++ 4  ++-| | YOTROK
            |    |  -+--+    |+---+    |  | |    || |||    || | +-P-HILA-
           -+---    |  -+---     -+---    |-+---  +-+++---  | | |DELPHIA
                    +---------------------+---------+-------+-| |
            +----   |+--+---------+------++-+-----+   +----   | |
            |    |  ++--+    |  +-+    | |--+    ||+--+    |  | |
            | 6  +--++--+ 1  +-++-+ 1  +-+--+ 1  +++--+ 1  ++ | |
           -+---       -+--- --++-+---   | -+---  |  -+-----+-+-+
                               ---                         ---
                       FIGURE 1. CIRCUITOUS DIAGRAM


       






                                   - 8 -



          __________________________________________________________
         |\                                                         \
         | \ 1. Logic gate.  Inputs A, B.  Output O = AB.            \
         |  \                                                         \
         | \ \ 2. Logic gate.  Inputs A, B, C.  Output O = A+BC.       \
         | |\ \                                                         \
         | | \ \ 3. Logic gate.  Inputs A, B.  Output O = A+AB.          \
         | |  \ \                                                         \
         | |  |\ \ 4. Logic gate.  Inputs A, B.  Output O = AB O+ -(A+-B)   \
         | |  | \ \                                                         \
         | |  |  \ \ 5. Logic gate.  Inputs A, B.  Output O = AO+A + AA       \
         | |  |   \ \                                                         \
         | |  |    \ \ 6. Uninitialized flip-flop.  Inputs none.  Output O = ? \
         | |  |     \ \                                                         \
         | |  |      \ \ 7. Flip-flop-flap.  Inputs A, B, C.  Output O = 1 if    \
         | |  |       \ \    A=0 or B+C=0 and A=1.  O = 0 if AC=1, B=0.  O = O| if \
         | |  |        \ \    AB=1, C=0.  O = ? if ABC=1.  O as yet undetermined   \
         | |  |         \ \    for other Warmenhovian inputs.  See Figure 2.        \
         | |  |          \ \                                                         \
         | |  |           \ \ 8. Bus line.                                            \
         | |  |            \ \_________________________________________________________\
         | |  |             \ |                                                         |
         | |  |             | |  _____________________________________________________  |
         | |  |             | |  |                              | |  |             | |  |
         | |  |             | |  |                              | |  |             | |  |
         | |  |             | |  |                              | |  |             | |  |
         | |  |             | |  |                              | |  |             | |  |
         | |  |             | |  |                              | |  |             | |  |
          \|__|             | |  |                               \|__|             | |  |
                            | |  |                                                 | |  |
                            | |  |                                                 | |  |
                            | |  |                                                 | |  |
                            | |  |                                                 | |  |
                            | |  |                                                 | |  |
                            | |  |                                                 | |  |
                            | |  |                                                 | |  |
                            | |  |                                                 | |  |
                            | |  |                                                 | |  |
                            | |  |                                                 | |  |
                            | |  |                                                 | |  |
                            | |  |                                                 | |  |
                            | |  |                                                 | |  |
                            | |  |                                                 | |  |
                            | |  |                                                 | |  |
                            | |  |                                                 | |  |
                            | |  |                                                 | |  |
                            | |  |                                                 | |  |
                             \|__|                                                  \|__|

                 Table 1.  Logical (and other) functions.





       






                                   - 9 -



       [Warning: The following picture will be garbled or  missing.
       Get a better output device.]










       -------------------------+----
      A                     +---+    |----+------------D
                            |   |    |    |
                                +----



                            |   |            |
                            +---+----        |
      B-------------------------+    |----+  |
                                +----|    |  |
                                          |  |
                                          |  |
                                          |  |
                                          |  |
                                |         |  |
      C-------------------------+----|    |  |
               +----------------+    |--+ |  |
               |                +----   | |  |
               |                        | |  |
               |                             |
               |                             |
               |                             |
               |            | | |            |
               |            | +-+----|       |
               |            +---+ +- +-------+
               |                +-+--
         1-----+










                         FIGURE 2. FLIP FLAP FLOP




       






                                  - 10 -



       [Warning:  The following picture will be garbled or missing.
       Get a better output device.]
           +---+
       ----+   |
       ----+   +----
       ----+   |
       ----+   +----
           |   |
       ----+   +----
       ----+   |
       ----+   +----
       ----+   |                     GATE TYPE 9.  BLACK BOX
       ----+ 9 +----                 INPUTS A1-8,  B1-8.
       ----+   |                     OUTPUT O1-8 = A1-8~B1-8
       ----+   +----
       ----+   |
       ----+   +----
           |   |
       ----+   +----
       ----+   |
       ----+   +----
       ----+   |
           +---+










                     FIGURE 1  (CONTINUED).  NEW YORK





















       






                                  - 11 -



       _3_._4_._2  _U_n_a_r_y _O_p_e_r_a_t_o_r_s

       The unary operators are & (logical AANNDD), V (logical OORR), and
       V-  (logical  XXOORR).  This  last  character  is  obtained   by
       overpunching  a  worm  (-)  on  a  V  (V).   The operator is
       inserted between the spot, two-spot, mesh, or what-have-you,
       and  the  integer,  thus:  .&123,  #V-123.   Multiple   unary
       operators  may  not be concatenated, thus the form #V-&123 is
       invalid. This will  be  covered  later  when  precedence  is
       discussed.  These operators perform their respective logical
       operations on all pairs of adjacent bits,  the  result  from
       the  first  and  last  bits  going into the first bit of the
       result.  The effect is that  of  rotating  the  operand  one
       place  to  the  right  and ANDing, ORing, or XORing with its
       initial value. Thus,  #&77  (binary  =  1001101)  is  binary
       0000000000000100  =  4,  #V77  is  binary 1000000001101111 =
       32879, and #V-77 is binary 1000000001101011 = 32875.

       _3_._4_._3  _P_r_e_c_e_d_e_n_c_e

       Precedence of operators is as follows:










       (The remainder of this page intentionally left blank)[2]



















       ____________________

       2. Keep in mind that the aim in designing  INTERCAL  was  to
          have no precedents.







                                  - 12 -



       This  precedence  (or  lack  thereof)  may  be  overruled by
       grouping expressions between pairs of sparks (') or  rabbit-
       ears    (").    Thus    '#165c/#203'~#358    (binary    value
       '10100101c/11001011'~101100110)  has  the   value   15,   but
       #165c/'#203~#358'  has the value 34915, and #165c/#203~#358 is
       invalid syntax and is completely valueless  (except  perhaps
       as  an educational tool to the programmer). A unary operator
       is applied  to  a  sparked  or  rabbit-eared  expression  by
       inserting  the  operator  immediately  following the opening
       spark or ears. Thus, the invalid  expression  #V-&123,  which
       was  described  earlier,  could  be  coded  as  'V-#&123'  or
       'V-"&#123"'.  Note:  In  the  interests  of  simplifying  the
       sometimes   overly-complex  form  of  expressions,  INTERCAL
       allows a spark-spot combination ('.) to be replaced  with  a
       wow  (!). Thus '.1~.2' is equivalent to !1~.2', and 'V.1c/.2'
       is equivalent to "V!1c/.2'".

       Combining a rabbit-ears with a spot to form a rabbit (".)  is
       not  permitted,  although  the  programmer is free to use it
       should  he  find  an  EBCDIC  reader  which  will   properly
       translate a 12-3-7-8 punch.

       Sparks  and/or  rabbit-ears must also be used to distinguish
       among such otherwise  ambiguous  subscripted  and  multiply-
       subscripted expressions as:

               ,1 SUB #1 ~ #2
               ,1 SUB ,2 SUB #1 #2 #3
               ,1 SUB " ,2 SUB " ,3 SUB #1 " #2 " " #3 "

       The  third  case may be isolated into either of its possible
       interpretations by simply changing some pairs of rabbit-ears
       to sparks, instead of adding more  ears  (which  would  only
       confuse  the  issue further). Ambiguous cases are defined as
       those for which the compiler being used finds  a  legitimate
       interpretation  which  is different from that which the user
       had in mind. See also section .


















       






                                  - 13 -



       _4_.  _S_T_A_T_E_M_E_N_T_S

       In  this  section  is  described  the  format  of   INTERCAL
       statements.

       _4_._1  _G_e_n_e_r_a_l _F_o_r_m_a_t

       Statements  may  be  entered in 'free format'. That is, more
       than one statement  may  occur  on  a  single  card,  and  a
       statement may begin on one card and end on a later one. Note
       that  if  this  is  done, all intervening cards and portions
       thereof must be  part  of  the  same  statement.  That  this
       restriction  is  necessary  is immediately apparent from the
       following example of what might occur if statements could be
       interlaced.

               DO .1 <- ".1c/'&:51~"#V-1c!12~;&75SUB"V-'V.1~
               DO .2 <- '"!1c/"&';V-79SUB",&7SUB:173"'~!V-9c/
               .2'c/,&1SUB:5~#33578"'"'"~'#65535c/"V-'V#&85'"'
               #8196'"'~.1"c/.2'~'#&5c/"'#1279c/#4351'~#65535"'

       The above statements are obviously  meaningless.  (For  that
       matter, so are the statements

               DO .1 <- ".1c/"&:51~"#V-1c/!12~;&75SUB"V-'V.1~
               .2'c/,&1SUB:5~#333578"'"'"~#65535c/"V-'V#&85'"'
               DO .2 <- '"!1c/"&';V-79SUB",&7SUB:173"'~!V-9c/
               #8196'"'~.1"c/.2'~'#&5c/"'#1279c/#4351'~#65535"'

       but this is not of interest here.)

       Spaces  may be used freely to enhance program legibility (or
       at least reduce program illegibility), with the  restriction
       that  no  word  of a statement identifier (see section ) may
       contain any spaces.

       _4_._2  _L_a_b_e_l_s

       A statement may begin with a llooggiiccaall lliinnee llaabbeell enclosed  in
       wax-wane  pairs (()). A statement may not have more than one
       label, although it is possible to omit the label entirely. A
       line label is any integer from 1 to  65535,  which  must  be
       unique  within each program. The user is cautioned, however,
       that many line labels between 1000 and 1999 are used in  the
       INTERCAL System Library functions.

       _4_._3  _I_d_e_n_t_i_f_i_e_r_s _a_n_d _Q_u_a_l_i_f_i_e_r_s

       After  the  line  label  (if  any),  must  follow one of the
       following statement identifiers: DO, PLEASE, or  PLEASE  DO.
       These  may be used interchangeably to improve the aesthetics
       of the program. The identifier is then followed  by  either,
       neither,  or  both  of  the  following  optional  parameters
       (qualifiers): (1) either of the  character  strings  NOT  or

       






                                  - 14 -



       N'T,   which   causes  the  statement  to  be  automatically
       abstained from (see section ) when execution begins, and (2)
       a number between 0 and 100, preceded  by  a  double-oh-seven
       (%),  which  causes the statement to have only the specified
       percent chance of being executed each time it is encountered
       in the course of execution.

       _4_._4  _S_t_a_t_e_m_e_n_t_s

       Following  the  qualifiers  (or,  if  none  are  used,   the
       identifier)  must  occur  one  of  the  13 valid operations.
       (Exception: see section .) These are described  individually
       in sections
        through .

       _4_._4_._1  _C_a_l_c_u_l_a_t_e

       The  INTERCAL  equivalent  of  the half-mesh (=) in FORTRAN,
       BASIC, PL/I, and others, is  represented  by  an  angle  (<)
       followed  by  a  worm  (-). This combination is read 'gets'.
       32-bit variables may be assigned 16-bit  values,  which  are
       padded  on  the left with 16 zero bits. 16-bit variables may
       be assigned 32-bit values only if the  value  is  less  than
       65535.  Thus,  to  invert  the  least significant bit of the
       first element of 16-bit 2-dimensional array  number  1,  one
       could write:

       ,1SUB#1#1 <- 'V-",1SUB#1#1"c/#1'~'#0c/#65535'

       Similarly  to  SNOBOL  and SPITBOL, INTERCAL uses the angle-
       worm to define the dimensions of  arrays.  An  example  will
       probably  best  describe the format.  To define 32-bit array
       number 7 as 3-dimensional, the first dimension being  seven,
       the second being the current value of 16-bit variable number
       seven,  and the third being the current value of the seventh
       element  of  16-bit  array  number  seven  (which  is   one-
       dimensional)  mingled  with  the  last  three bits of 32-bit
       variable number seven, one would  write  (just  before  they
       came to take him away):

       ;7 <- #7 BY .7 BY ",7SUB#7"c/':7~#7'

       This is, of course, different from the statement:

       ;7 <- #7 BY .7 BY ,7SUB"#7c/':7~#7'"

       INTERCAL  also permits the redefining of array dimensioning,
       which is done the same way as is the  initial  dimensioning.
       All   values   of   items   in   an   array  are  lost  upon
       redimensioning, unless they have been STASHed  (see  section
       ),  in  which  case  restoring  them  also  restores the old
       dimensions.



       






                                  - 15 -



       _4_._4_._2  _N_E_X_T

       The NEXT statement is used both for subroutine calls and for
       unconditional transfers. This statement takes the form:

       DO (label) NEXT

       (or, of course,

       PLEASE DO (label) NEXT

       etc.), where (label) represents any logical line label which
       appears in the program. The effect of such a statement is to
       transfer control to the statement specified, and to store in
       a push down list (which is  initially  empty)  the  location
       from  which  the  transfer takes place. Items may be removed
       from this list and may be discarded or used to return to the
       statement immediately following the  NEXT  statement.  These
       operations are described in sections
        and
        respectively.   The  programmer  is  generally  advised  to
       discard any stack  entries  which  he  does  not  intend  to
       utilize,  since the stack has a maximum depth of 79 entries.
       A program's attempting to initiate an 80th level of  NEXTing
       will  result  in  the  fatal  error  message,  "PROGRAM  HAS
       DISAPPEARED INTO THE BLACK LAGOON."

       _4_._4_._3  _F_O_R_G_E_T

       The statement PLEASE FORGET exp, where  exp  represents  any
       expression   (except  colloquial  and  facial  expressions),
       causes the expression to be  evaluated,  and  the  specified
       number  of  entries to be removed from the NEXTing stack and
       discarded. An attempt to FORGET more levels of NEXTing  than
       are  currently  stacked  will cause the stack to be emptied,
       and no error condition is indicated.  This  is  because  the
       condition  is not considered to be an error. As described in
       section , it is good programming practice to  execute  a  DO
       FORGET  #1  after using a NEXT statement as an unconditional
       transfer, so that the stack does not get cluttered  up  with
       unused entries:

               DO (123) NEXT
               .
               .
         (123) DO FORGET #1

       _4_._4_._4  _R_E_S_U_M_E

       The  statement  PLEASE  RESUME  exp  has  the same effect as
       FORGET, except that  program  control  is  returned  to  the
       statement  immediately  following  the  NEXT statement which
       stored in the stack the last entry to be removed. Note  that
       a  rough  equivalent of the FORTRAN computed GO TO and BASIC

       






                                  - 16 -



       ON exp GO TO is performed by a sequence of the form:

               DO (1) NEXT
               .
               .
           (1) DO (2) NEXT
               PLEASE FORGET #1
               .
               .
           (2) DO RESUME .1

       Unlike the FORGET  statement,  an  attempt  to  RESUME  more
       levels  of  NEXTing than has been stacked will cause program
       termination. See also section .

       _4_._4_._5  _S_T_A_S_H

       Since  subroutines  are  not   explicitly   implemented   in
       INTERCAL,  the  NEXT  and  RESUME statements must be used to
       execute common routines. However, as  these  routines  might
       use  the same variables as the main program, it is necessary
       for them to save the values of any  variables  whose  values
       they   alter,  and  later  restore  them.  This  process  is
       simplified by the STASH statement, which  has  the  form  DO
       STASH  list,  where  list represents a string of one or more
       variable or array names,  separated  by  intersections  (+).
       Thus

       PLEASE STASH .123+:123+,123

       stashes  the  values  of two variables and one entire array.
       The values are left intact, and copies thereof are saved for
       later retrieval by (what else?)  the RETRIEVE statement (see
       section ). It is not possible to STASH single array items.

       _4_._4_._6  _R_E_T_R_I_E_V_E

       PLEASE RETRIEVE list restores the previously STASHed  values
       of  the  variables  and arrays named in the list. If a value
       has been stashed more than once, the most  recently  STASHed
       values are RETRIEVEd, and a second RETRIEVE will restore the
       second  most recent values STASHed. Attempting to RETRIEVE a
       value which has not been STASHed will result  in  the  error
       message, "THROW STICK BEFORE RETRIEVING."

       _4_._4_._7  _I_G_N_O_R_E

       The   statement   DO   IGNORE  list  causes  all  subsequent
       statements to have no effect upon  variables  and/or  arrays
       named in the list. Thus, for example, after the sequence

               DO .1 <- #1
               PLEASE IGNORE .1
               DO .1 <- #0








                                  - 17 -



       16-bit  variable  number  1  would  have the value 1, not 0.
       Inputting (see section ) into an IGNOREd variable  also  has
       no  effect.  The  condition  is  annulled  via  the REMEMBER
       statement (see section ). Note  that,  when  a  variable  is
       being   IGNOREd,  its  value,  though  immutable,  is  still
       available for use in expressions and the like.

       _4_._4_._8  _R_E_M_E_M_B_E_R

       PLEASE REMEMBER list terminates the  effect  of  the  IGNORE
       statement for all variables and/or arrays named in the list.
       It  does not matter if a variable has been IGNOREd more than
       once, nor is it an  error  if  the  variable  has  not  been
       IGNOREd at all.

       _4_._4_._9  _A_B_S_T_A_I_N

       INTERCAL contains no simple equivalent to an IF statement or
       computed  GO  TO,  making  it  difficult  to combine similar
       sections of code into a single  routine  which  occasionally
       skips  around  certain statements. The IGNORE statement (see
       section ) is helpful in some cases, but a more viable method
       is often required. In keeping  with  the  goal  of  INTERCAL
       having  nothing  in  common with any other language, this is
       made possible via the ABSTAIN statement.

       This statement takes on one of two forms. It may not take on
       both at any one time. DO ABSTAIN  FROM  (label)  causes  the
       statement   whose  logical  line  label  is  (label)  to  be
       abstained from. PLEASE ABSTAIN FROM gerund list  causes  all
       statements of the specified type(s) to be abstained from, as
       in

             PLEASE ABSTAIN FROM STASHING
             PLEASE ABSTAIN FROM IGNORING + FORGETTING
             PLEASE ABSTAIN FROM NEXTING
          or PLEASE ABSTAIN FROM CALCULATING

       Statements  may  also be automatically abstained from at the
       start of execution via the NOT or N'T parameter (see section
       ).

       If, in the course of execution, a statement  is  encountered
       which  is  being  abstained  from, it is ignored and control
       passes to the next statement in the program (unless it, too,
       is being abstained from).

       The statement DO ABSTAIN FROM ABSTAINING is perfectly valid,
       as is DO ABSTAIN FROM REINSTATING (although this  latter  is
       not  usually recommended). However, the statement DO ABSTAIN
       FROM GIVING UP is not accepted, even though  DON'T  GIVE  UP
       is.



       






                                  - 18 -



       _4_._4_._1_0  _R_E_I_N_S_T_A_T_E

       The  REINSTATE  statement,  like  the  ABSTAIN,  takes as an
       argument either a line label or a gerund list. No other form
       of argument is permitted. For example, the following  is  an
       invalid argument:

               Given: x!=0, y!=0,  Prove: x+y=0
               Since x!=0, then x+1!=1, x+a!=a, x+y!=y.
               But what is y? y is anything but 0.
               Thus x+y != anything but 0.
               Since x+y cannot equal anything but 0, x+y=0.
                                                                Q.E.D.

       REINSTATEment nullifies the effects of an abstention. Either
       form  of  REINSTATEment  can  be used to "free" a statement,
       regardless of whether the statement was  abstained  from  by
       gerund  list,  line  label,  or  NOT. Thus, PLEASE REINSTATE
       REINSTATING is  not  necessarily  an  irrelevant  statement,
       since it might free a DON'T REINSTATE command or a REINSTATE
       the  line  label  of  which  was abstained from. However, DO
       REINSTATE GIVING UP is invalid, and attempting to  REINSTATE
       a  GIVE UP statement by line label will have no effect. Note
       that this insures that DON'T GIVE UP will always be  a  "do-
       nothing" statement.

       _4_._4_._1_1  _G_I_V_E _U_P

       PLEASE  GIVE  UP  is used to exit from a program. It has the
       effect of a PLEASE RESUME #80. DON'T GIVE UP,  as  noted  in
       section , is effectively a null statement.

       _4_._4_._1_2  _I_n_p_u_t

       Input  is  accomplished with the statement DO WRITE IN list,
       where list represents a string of variables and/or  elements
       of   arrays,   separated   by   intersections.  Numbers  are
       represented on cards, each number on  a  separate  card,  by
       spelling  out  each  digit  (in  English) and separating the
       digits with one or more spaces. A zero (0) may be spelled as
       either ZERO or OH.  Thus the range of (32-bit) input  values
       permissible  extends from ZERO (or OH) through FOUR TWO NINE
       FOUR NINE SIX SEVEN TWO NINE FIVE.

       Attempting to write in a value greater than or equal to  SIX
       FIVE FIVE THREE SIX for a 16-bit variable will result in the
       error message, "DON'T BYTE OFF MORE THAN YOU CAN CHEW."

       _4_._4_._1_3  _O_u_t_p_u_t

       Values may be output to the printer, one value per line, via
       the  statement  DO  READ  OUT  list, where the list contains
       variables, array elements, and/or constants.  Output  is  in
       the   form   of   "extended"  Roman  numerals  (also  called

       






                                  - 19 -



       "butchered" Roman numerals), with an overline indicating the
       value  below  is  "times  1000",  and   lower-case   letters
       indicating "times 1000000". Zero is indicated by an overline
       with  no  character  underneath. Thus, the range of (32-bit)
       output values possible is from
       _

       through
       __      ____________
       ivccxcivCMLXVIICCXCV.
       Note: For values whose residues modulo 1000000 are less than
       4000, M is used to represent 1000; for values whose residues
       are 4000 or greater,
       _
       I
       is used. Thus #3999 would read out as  MMMCMXCIX  [3]  while
       #4000 would readout as
       __
       IV
       Similar rules apply to the use of
       _
       M
       and i for 1000000, and to that of m and
       _
       i
       for 1000000000.

       _4_._5  _C_o_m_m_e_n_t_s

       Unrecognizable statements, as noted in section , are flagged
       with  a splat (*) during compilation, and are not considered
       fatal errors unless they are encountered  during  execution,
       at  which  time the statement (as input at compilation time)
       is printed and execution is terminated. This allows  for  an
       interesting  (and,  by necessity, unique) means of including
       comments in an INTERCAL listing. For example, the statement:

       *       PLEASE NOTE THAT THIS LINE HAS NO EFFECT

       will be ignored during execution due to the inclusion of the
       NOT qualifier.  User-supplied error messages are  also  easy
       to implement:

       *       DO SOMETHING ABOUT OVERFLOW IN ;3

       as are certain simple conditional errors:



       ____________________

       3. The original INTERCAL-72 manual claimed that #3999 should
          render  as MMMIM, but the C-INTERCAL developers have been
          unable to  find  an  algorithm  that  does  this  and  is
          consistent with the rest of the rules.







                                  - 20 -



       * (123) DON'T YOU REALIZE THIS STATEMENT SHOULD ONLY BE ENCOUNTERED
                       ONCE?
               PLEASE REINSTATE (123)

       This  pair of statements will cause an error exit the second
       time they are encountered. Caution!!  The  appearance  of  a
       statement identifier in an intended comment will be taken as
       the  beginning  of  a new statement. Thus, the first comment
       example above could not have been:

       *       PLEASE NOTE THAT THIS LINE DOES NOTHING

       The third example, however, is valid, despite the appearance
       of two cases of D-space-O, since INTERCAL  does  not  ignore
       extraneous spaces in statement identifiers.








































       






                                  - 21 -



       _5_.  _S_U_B_R_O_U_T_I_N_E _L_I_B_R_A_R_Y

       INTERCAL  provides  several  built-in  subroutines  to which
       control can be transferred to  perform  various  operations.
       These operations include many useful functions which are not
       easily   representable   in   INTERCAL,  such  as  addition,
       subtraction, etc.

       _5_._1  _U_s_a_g_e

       In general, the operands are .1, .2, etc., or :1, :2,  etc.,
       and  the  result(s)  are  stored in what would have been the
       next operand(s). For instance, one routine adds .1 to .2 and
       stores the sum  in  .3,  with  .4  being  used  to  indicate
       overflow.  All  variables  not  used  for  results  are left
       unchanged.

       _5_._2  _A_v_a_i_l_a_b_l_e _F_u_n_c_t_i_o_n_s

       At the time of  this  writing,  only  the  most  fundamental
       operations  are  offered  in the library, as a more complete
       selection  would  require  prohibitive  time  and  core   to
       implement.  These  functions, along with their corresponding
       entry points (entered via DO (entry) NEXT) are listed below.































       






                                  - 22 -



        (1000) .3 <- .1 plus .2, error exit on overflow
        (1009) .3 <- .1 plus .2
               .4 <- #1 if no overflow, else .4 <- #2
        (1010) .3 <- .1 minus .2, no action on overflow
        (1020) .1 <- .1 plus #1, no action on overflow
        (1030) .3 <- .1 times .2, error exit on overflow
        (1039) .3 <- .1 times .2
               .4 <- #1 if no overflow, else .4 <- #2
        (1040) .3 <- .1 divided by .2
               .3 <- #0 if .2 is #0
        (1050) .2 <- :1 divided by .1, error exit on overflow
               .2 <- #0 if .1 is #0

        (1500) :3 <- :1 plus :2, error exit on overflow
        (1509) :3 <- :1 plus :2
               :4 <- #1 if no overflow, else :4 <- #2
        (1510) :3 <- :1 minus :2, no action on overflow
        (1520) :1 <- .1 concatenated with .2
        (1525) This subroutine is intended solely for internal
               use within the subroutine library and is therefore
               not described here. Its effect is to shift .3
               logically 8 bits to the left.
        (1530) :1 <- .1 times .2
        (1540) :3 <- :1 times :2, error exit on overflow
        (1549) :3 <- :1 times :2
               :4 <- #1 if no overflow, else :4 <- #2
        (1550) :3 <- :1 divided by :2
               :3 <- #0 if :2 is #0

        (1900) .1 <- uniform random no. from #0 to #65535
        (1910) .2 <- normal random no. from #0 to .1, with
                     standard deviation .1 divided by #12






























                                  - 23 -



       _6_.  _P_R_O_G_R_A_M_M_I_N_G _H_I_N_T_S

       For the user  looking  to  become  more  familiar  with  the
       INTERCAL language, we present in this section an analysis of
       a  complex  program,  as well as some suggested projects for
       the ambitious programmer.

       Considering the  effort  involved  in  writing  an  INTERCAL
       program,  it  was decided in putting together this manual to
       use an already existing program  for  instructive  analysis.
       Since  there  was  only  one such program available, we have
       proceeded to use it. It is known  as  the  "INTERCAL  System
       Library."

       _6_._1  _D_e_s_c_r_i_p_t_i_o_n

       The program listing is in section . It is in the same format
       as  would  be produced by the Princeton INTERCAL compiler in
       FORMAT mode with WIDTH=62 (see section ). For a  description
       of the functions performed by the Library, see section .

       _6_._2  _A_n_a_l_y_s_i_s

       We  shall  not  attempt to discuss here the algorithms used,
       but rather we shall point out some of the general techniques
       applicable to a wide range of problems.

       Statements 10, 14, 15, and 26 make up a virtual "computed GO
       TO".  When  statement  10  is   executed,   control   passes
       eventually  to  statement  16 or 11, depending on whether .5
       contains  #1  or  #2,  respectively.  The  value  of  .5  is
       determined  in statement 9, which demonstrates another handy
       technique.  To turn an expression, exp, with value #0 or #1,
       into #1 or #2 (for use in a "GO  TO"),  use  "V-'exp'c/#1"~#3.
       To  reverse  the condition (i.e., convert #0 to #2 and leave
       #1 alone) use "V-'exp'c/#2"~#3.

       Certain conditions are easily checked. For example, to  test
       for zero, select the value from itself and select the bottom
       bit  (see  statement  54).   To test for all bits being 1's,
       select the value from itself and select the  top  bit.   The
       test  for  greater than, performed in statements 219 and 220
       on 32-bit values, employs binary logical  operations,  which
       are performed as follows:

       'V-.1c/.2'~'#0c/#65535'

       for 16-bit values or, for 32-bit values:

               "'V-":1~'#65535c/30'"c/":2~'#65535c/#0'"'~'#0
               c/#65535'"c/"'V-":1~'#0c/#65535'"c/":2~'#0
               c/#65535'"'~'#0c/#65535'"

       (The proofs are left as an exercise to the reader.)

       






                                  - 24 -



       Testing  for  greater-than  with  16-bit  values is somewhat
       simpler and is done with the pair of statements:

               DO .C <- 'V-.Ac/.B'~'#0c/#65535'
               DO .C <- '&"'.A~.C'~'"V-'V-.C~.C'c/#32768"
                       ~"#0c/#65535"'"c/".C~.C"'~#1

       This sets .C (a dummy variable) to #1 if .A  >  .B,  and  #0
       otherwise. The expression may be expanded as described above
       to instead set .C to #1 or #2.

       Note    also    in   statement   220   the   occurrence   of
       ~"#65535c/#65535".  Although  these  operations  select   the
       entire  value,  they are not extraneous, as they ensure that
       the forthcoming V-s will be operating on 32-bit values.

       In  several  virtual  computed  GO  TOs  the  DO  FORGET  #1
       (statement  15  in  the  earlier  example) has been omitted,
       since the next transfer of control would be a DO RESUME  #1.
       By  making  this  a  DO RESUME #2 instead, the FORGET may be
       forgotten.

       In statement 64, note that .2 is STASHed twice by  a  single
       statement. This is perfectly legal.

       Lastly,   note  in  statements  243  and  214  respectively,
       expressions for shifting 16- and 32-bit variables  logically
       one  place  to  the left.  Statement 231 demonstrates right-
       shifting for 32-bit variables.


























       






                                  - 25 -



       _6_._3  _P_r_o_g_r_a_m _L_i_s_t_i_n_g






















































       






                                  - 26 -



            1          (1000)  PLEASE IGNORE .4
            2                  PLEASE ABSTAIN FROM (1005)
            3          (1009)  DO STASH .1 + .2 + .5 + .6
            4                  DO .4 <- #1
            5                  DO (1004) NEXT
            6          (1004)  PLEASE FORGET #1
            7                  DO .3 <- 'V-.1c/.2'~'#0c/#65535'
            8                  DO .6 <- '&.1c/.2'~'#0c/#65535'
            9                  PLEASE DO .5 <- "V-!6~#32768'c/#1"~#3
           10                  DO (1002) NEXT
           11                  DO .4 <- #2
           12          (1005)  DO (1006) NEXT
       *   13          (1999)  DOUBLE OR SINGLE PRECISION OVERFLOW
           14          (1002)  DO (1001) NEXT
           15          (1006)  PLEASE FORGET #1
           16                  DO .5 <- 'V-"!6~.6'~#1"c/#1'~#3
           17                  DO (1003) NEXT
           18                  DO .1 <- .3
           19                  DO .2 <- !6c/#0'~'#32767c/#1'
           20                  DO (1004) NEXT
           21          (1003)  DO (1001) NEXT
           22                  DO REINSTATE (1005)
           23          (1007)  PLEASE RETRIEVE .1 + .2 + .5 + .6
           24                  DO REMEMBER .4
           25                  PLEASE RESUME #2
           26          (1001)  DO RESUME .5
           27          (1010)  DO STASH .1 + .2 + .4
           28                  DO .4 <- .1
           29                  DO .1 <- 'V-.2c/#65535'~'#0c/#65535'
           30                  DO (1020) NEXT
           31                  PLEASE DO .2 <- .4
           32                  PLEASE DO (1009) NEXT
           33                  DO RETRIEVE .1 + .2 + .4
           34                  PLEASE RESUME #1
           35          (1020)  DO STASH .2 + .3
           36                  DO .2 <- #1
           37                  PLEASE DO (1021) NEXT
           38          (1021)  DO FORGET #1
           39                  DO .3 <- "V-!1~.2'c/#1"~#3
           40                  PLEASE DO .1 <- 'V-.1c/.2'~'#0c/#65535'
           41                  DO (1022) NEXT
           42                  DO .2 <- !2c/#0'~'#32767c/#1'
           43                  DO (1021) NEXT
           44          (1023)  PLEASE RESUME .3
           45          (1022)  DO (1023) NEXT
           46                  PLEASE RETRIEVE .2 + .3
           47                  PLEASE RESUME #2
           48          (1030)  DO ABSTAIN FROM (1033)
           49                  PLEASE ABSTAIN FROM (1032)
           50          (1039)  DO STASH :1 + .5
           51                  DO (1530) NEXT
           52                  DO .3 <- :1~#65535
           53                  PLEASE DO .5 <- :1~'#65280c/#65280'
           54                  DO .5 <- 'V-"!5~.5'~#1"c/#1'~#3








                                  - 27 -



           55                  DO (1031) NEXT
           56          (1032)  DO (1033) NEXT
           57                  DO (1999) NEXT
           58          (1031)  DO (1001) NEXT
           59          (1033)  DO .4 <- .5
           60                  DO REINSTATE (1032)
           61                  PLEASE REINSTATE (1033)
           62                  DO RETRIEVE :1 + .5
           63                  PLEASE RESUME #2
           64          (1040)  PLEASE STASH .1 + .2 + .2 + :1 + :2 + :3
           65                  DO .2 <- #0
           66                  DO (1520) NEXT
           67                  DO STASH :1
           68                  PLEASE RETRIEVE .2
           69                  DO .1 <- .2
           70                  DO .2 <- #0
           71                  PLEASE DO (1520) NEXT
           72                  DO :2 <- :1
           73                  DO RETRIEVE .1 + .2 + :1
           74                  DO (1550) NEXT
           75                  PLEASE DO .3 <- :3
           76                  DO RETRIEVE :1 + :2 + :3
           77                  DO RESUME #1
           78          (1050)  PLEASE STASH :2 + :3 + .5
           79                  DO :2 <- .1
           80                  PLEASE DO (1550) NEXT
           81                  DO .5 <- :3~'#65280c/#65280'
           82                  DO .5 <- 'V-"!5~.5'~#1"c/#1'~#3
           83                  DO (1051) NEXT
           84                  DO (1999) NEXT
           85          (1051)  DO (1001) NEXT
           86                  DO .2 <- :3
           87                  PLEASE RETRIEVE :2 + :3 + .5
           88                  DO RESUME #2
           89          (1500)  PLEASE ABSTAIN FROM (1502)
           90                  PLEASE ABSTAIN FROM (1506)
           91          (1509)  PLEASE STASH :1 + .1 + .2 + .3 + .4 + .5 + .6
           92                  DO .1 <- :1~#65535
           93                  PLEASE DO .2 <- :2~#65535
           94                  DO (1009) NEXT
           95                  DO .5 <- .3
           96                  PLEASE DO .6 <- .4
           97                  DO .1 <- :1~'#65280c/#65280'
           98                  DO .2 <- :2~'#65280c/#65280'
           99                  DO (1009) NEXT
          100                  DO .1 <- .3
          101                  PLEASE DO (1503) NEXT
          102                  DO .6 <- .4
          103                  DO .2 <- #1
          104                  DO (1009) NEXT
          105                  DO .1 <- .3
          106                  DO (1501) NEXT
          107          (1504)  PLEASE RESUME .6
          108          (1503)  DO (1504) NEXT








                                  - 28 -



          109          (1501)  DO .2 <- .5
          110                  DO .5 <- 'V-"'&.6c/.4'~#1"c/#2'~#3
          111                  DO (1505) NEXT
          112          (1506)  DO (1502) NEXT
          113                  PLEASE DO (1999) NEXT
          114          (1505)  DO (1001) NEXT
          115          (1502)  DO :4 <- .5
          116                  DO (1520) NEXT
          117                  DO :3 <- :1
          118                  PLEASE RETRIEVE :1 + .1 + .2 + .3 + .4 + .5 + .6
          119                  DO REINSTATE (1502)
          120                  DO REINSTATE (1506)
          121                  PLEASE RESUME #3
          122          (1510)  DO STASH :1 + :2 + :4
          123                  DO :1 <- "'V-":2~'#65535c/#0'"c/#65535'
                                   ~'#0c/#65535'"c/"'V-":2~'#0c/#65535'
                                   "c/#65535'~'#0c/#65535'"
          124                  DO :2 <- #1
          125                  DO (1509) NEXT
          126                  PLEASE RETRIEVE :1
          127                  DO :2 <- :3
          128                  PLEASE DO (1509) NEXT
          129                  DO RETRIEVE :2 + :4
          130                  PLEASE RESUME #1
          131          (1520)  PLEASE STASH .3 + .4
          132                  DO .3 <- .1~#43690
          133                  DO (1525) NEXT
          134                  PLEASE DO .4 <- 'V.3c/".2~#43690"'~'#0c/#65535'
          135                  DO .3 <- .1~#21845
          136                  PLEASE DO (1525) NEXT
          137                  DO :1 <- .4c/"'V.3c/".2~#21845"'~'#0c/#65535'"
          138                  PLEASE RETRIEVE .3 + .4
          139                  DO RESUME #1
          140          (1525)  DO .3 <- '"'"'"!3c/#0'~'#32767c/#1'"c/#0'
                                   ~'#32767c/#1'"c/#0'~'#16383c/#3'"c/#0'
                                   ~'#4095c/#15'
          141                  PLEASE RESUME #1
          142          (1530)  DO STASH :2 + :3 + .3 + .5
          143                  DO :1 <- #0
          144                  DO :2 <- .2
          145                  DO .3 <- #1
          146                  DO (1535) NEXT
          147          (1535)  PLEASE FORGET #1
          148                  DO .5 <- "V-!1~.3'c/#1"~#3
          149                  DO (1531) NEXT
          150                  DO (1500) NEXT
          151                  DO :1 <- :3
          152                  PLEASE DO (1533) NEXT
          153          (1531)  PLEASE DO (1001) NEXT
          154          (1533)  DO FORGET #1
          155                  DO .3 <- !3c/#0'~'#32767c/#1'
          156                  DO :2 <- ":2~'#0c/#65535'"c/"'":2~'#32767
                                   c/#0'"c/#0'~'#32767c/#1'"
          157                  PLEASE DO .5 <- "V-!3~.3'c/#1"~#3








                                  - 29 -



          158                  DO (1532) NEXT
          159                  DO (1535) NEXT
          160          (1532)  DO (1001) NEXT
          161                  PLEASE RETRIEVE :2 + :3 + .3 + .5
          162                  DO RESUME #2
          163          (1540)  PLEASE ABSTAIN FROM (1541)
          164                  DO ABSTAIN FROM (1542)
          165          (1549)  PLEASE STASH :1 + :2 + :4 + :5 + .1 + .2 + .5
          166                  DO .1 <- :1~#65535
          167                  PLEASE DO .2 <- :2~'#65280c/#65280'
          168                  DO .5 <- :1~'#65280c/#65280'
          169                  DO (1530) NEXT
          170                  DO :3 <- :1
          171                  DO .2 <- :2~#65535
          172                  PLEASE DO (1530) NEXT
          173                  DO :5 <- :1
          174                  DO .1 <- .5
          175                  DO (1530) NEXT
          176                  DO :4 <- :1
          177                  PLEASE DO :1 <- ":3~'#65280c/#65280'"
                                   c/":4~'#65280c/#65280'"
          178                  DO .5 <- ':1~:1'~#1
          179                  DO .2 <- :2~'#65280c/#65280'
          180                  DO (1530) NEXT
          181                  PLEASE DO .5 <- '"':1~:1'~#1"c/.5'~#3
          182                  DO .1 <- :3~#65535
          183                  DO .2 <- #0
          184                  DO (1520) NEXT
          185                  PLEASE DO :2 <- :1
          186                  PLEASE DO .1 <- :4~#65535
          187                  DO (1520) NEXT
          188                  DO (1509) NEXT
          189                  DO .5 <- !5c/":4~#3"'~#15
          190                  DO :1 <- :3
          191                  DO :2 <- :5
          192                  DO (1509) NEXT
          193                  PLEASE DO .5 <- !5c/":4~#3"'~#172
          194                  DO .5 <- 'V-"!5~.5'~#1"c/#1'~#3
          195                  PLEASE RETRIEVE :4
          196          (1541)  DO :4 <- .5
          197                  DO (1543) NEXT
          198          (1542)  DO (1544) NEXT
          199                  PLEASE DO (1999) NEXT
          200          (1543)  DO (1001) NEXT
          201          (1544)  DO REINSTATE (1541)
          202                  PLEASE REINSTATE (1542)
          203                  PLEASE RETRIEVE :1 + :2 + :5 + .1 + .2 + .5
          204                  DO RESUME #2
          205          (1550)  DO STASH :1 + :4 + :5 + .5
          206                  DO :3 <- #0
          207                  DO .5 <- 'V-"':2~:2'~#1"c/#1'~#3
          208                  PLEASE DO (1551) NEXT
          209                  DO :4 <- #1
          210                  PLEASE DO (1553) NEXT








                                  - 30 -



          211          (1553)  DO FORGET #1
          212                  DO .5 <- 'V-":2~'#32768c/#0'"c/#2'~#3
          213                  DO (1552) NEXT
          214                  DO :2 <- ":2~'#0c/#65535'"c/"'":2~'#32767
                                   c/#0'"c/#0'~'#32767c/#1'"
          215                  PLEASE DO :4 <- ":4~'#0c/#65535'"c/"'":4
                                   ~'#32767c/#0'"c/#0'~'#32767c/#1'"
          216                  DO (1553) NEXT
          217          (1552)  DO (1001) NEXT
          218          (1556)  PLEASE FORGET #1
          219                  DO :5 <- "'V-":1~'#65535c/#0'"c/":2
                                   ~'#65535c/#0'"'~'#0c/#65535'"c/"'
                                   V-":1~'#0c/#65535'"c/":2~'#0c/
                                   #65535'"'~'#0c/#65535'"
          220                  DO .5 <- 'V-"'&"':2~:5'~'"'V-"'V-":5~:5
                                   "~"#65535c/#65535"'~'#65535c/#0'"c/
                                   #32768'~'#0c/#65535'"c/"'V-":5~:5"
                                   ~"#65535c/#65535"'~'#0c/#65535'"'"c/"'
                                   :5~:5'~#1"'~#1"c/#2'~#3
          221                  DO (1554) NEXT
          222                  DO :5 <- :3
          223                  DO (1510) NEXT
          224                  PLEASE DO :1 <- :3
          225                  DO :3 <- "'V":4~'#65535c/#0'"c/":5~'#65535
                                   c/#0'"'~'#0c/#65535'"c/"'V":4~'#0
                                   c/#65535'"c/":5~'#0c/#65535'"'~'#0
                                   c/#65535'"
          226                  DO (1555) NEXT
          227          (1554)  PLEASE DO (1001) NEXT
          228          (1555)  DO FORGET #1
          229                  DO .5 <- "V-':4~#1'c/#2"~#3
          230                  DO (1551) NEXT
          231                  DO :2 <- ":2~'#0c/#65534'"c/":2~'#65535c/#0'"
          232                  DO :4 <- ":4~'#0c/#65534'"c/":4~'#65535c/#0'"
          233                  PLEASE DO (1556) NEXT
          234          (1551)  DO (1001) NEXT
          235                  PLEASE RETRIEVE :1 + :4 + :5 + .5
          236                  PLEASE RESUME #2
          237          (1900)  DO STASH .2 + .3 + .5
          238                  DO .1 <- #0
          239                  DO .2 <- #1
          240                  PLEASE DO (1901) NEXT
          241          (1901)  DO FORGET #1
          242                  DO %50 .1 <- 'V.1c/.2'~'#0c/#65535'
          243                  DO .2 <- !2c/#0'~'#32767c/#1'
          244                  PLEASE DO .5 <- "V-!2~.2'c/#1"~#3
          245                  DO (1902) NEXT
          246                  DO (1901) NEXT
          247          (1902)  DO (1001) NEXT
          248                  DO RETRIEVE .2 + .3 + .5
          249                  PLEASE RESUME #2
          250          (1910)  PLEASE STASH .1 + .3 + .5 + :1 + :2 + :3
          251                  DO .3 <- #65524
          252                  DO :1 <- #6








                                  - 31 -



          253                  DO (1911) NEXT
       *  254                  PLEASE NOTE THAT YOU CAN'T GET THERE FROM HERE
          255          (1912)  DO (1001) NEXT
          256          (1911)  DO FORGET #1
          257                  PLEASE DO (1900) NEXT
          258                  DO :2 <- .1
          259                  DO (1500) NEXT
          260                  PLEASE DO :1 <- :3
          261                  DO .1 <- .3
          262                  DO (1020) NEXT
          263                  PLEASE DO .3 <- .1
          264                  DO .5 <- 'V-"!3~.3'~#1"c/#2'~#3
          265                  DO (1912) NEXT
          266                  DO .1 <- #12
          267                  PLEASE DO (1050) NEXT
          268                  DO RETRIEVE .1
          269                  DO (1530) NEXT
          270                  DO :2 <- #32768
          271                  DO (1500) NEXT
          272                  PLEASE DO .2 <- :3~'#65280c/#65280'
          273                  PLEASE RETRIEVE .3 + .5 + :1 + :2 + :3
          274                  DO RESUME #1








































                                  - 32 -



       _6_._4  _P_r_o_g_r_a_m_m_i_n_g _S_u_g_g_e_s_t_i_o_n_s

       For the novice INTERCAL programmer, we provide here  a  list
       of suggested INTERCAL programming projects:

       Write an integer exponentiation subroutine.  :1 <- .1 raised
       to the .2 power.

       Write  a  double-precision  sorting subroutine. Given 32-bit
       array ;1 of size :1,  sort  the  contents  into  numerically
       increasing order, leaving the results in ;1.

       Generate a table of prime numbers.

       Put   together   a   floating-point  library,  using  32-bit
       variables to represent floating-point numbers (let the upper
       half  be  the  mantissa  and   the   lower   half   be   the
       characteristic).    The   library   should   be  capable  of
       performing     floating-point     addition,     subtraction,
       multiplication,   and  division,  as  well  as  the  natural
       logarithm function.

       Program a Fast Fourier Transform (FFT).  This project  would
       probably entail the writing of the floating-point library as
       well as sine and cosine functions.

       Calculate, to :1 places, the value of pi.




























       






                                  - 33 -



       _7_.  _E_R_R_O_R _M_E_S_S_A_G_E_S

       Due  to  INTERCAL's  implementation  of  comment  lines (see
       section  4.5),  most  error  messages  are  produced  during
       execution  instead of during compilation.  All errors except
       those not causing immediate termination of program execution
       are treated as fatal.

       _7_._1  _F_o_r_m_a_t

       All error messages appear in the following form:

               ICLnnnI (error message)
                       ON THE WAY TO STATEMENT nnnn
                       CORRECT SOURCE AND RESUBMIT

       The message varies depending upon the error  involved.   For
       undecodable  statements the message is the statement itself.
       The second  line  tells  which  statement  would  have  been
       executed  next had the error not occurred.  Note that if the
       error  is  due  to  80  attempted  levels  of  NEXTing,  the
       statement  which  would  have been executed next need not be
       anywhere near the statement causing the error.

       _7_._2  _M_e_s_s_a_g_e_s

       Brief descriptions of the different error types  are  listed
       below according to message number.

        000 An  undecodable  statement  has been encountered in the
            course of execution. Note that keypunching  errors  can
            be   slightly   disastrous,   since  if  'FORGET'  were
            misspelled F-O-R-G-E-R, the results would probably  not
            be  those  desired.  Extreme misspellings may have even
            more surprising consequences. For example,  misspelling
            'FORGET' R-E-S-U-M-E could have drastic results.

        017 An expression contains a syntax error.

        079 Improper use has been made of statement identifiers.

        099 Improper use has been made of statement identifiers.

        123 Program has attempted 80 levels of NEXTing.

        129 Program  has  attempted  to  transfer to a non-existent
            line label.

        139 An ABSTAIN or REINSTATE  statement  references  a  non-
            existent line label.

        182 A line label has been multiply defined.



       






                                  - 34 -



        197 An invalid line label has been encountered.

        200 An expression involves an unidentified variable.

        240 An  attempt  has been made to give an array a dimension
            of zero.

        241 Invalid  dimensioning  information  was   supplied   in
            defining or using an array.

        275 A 32-bit value has been assigned to a 16-bit variable.

        436 A retrieval has been attempted for an unSTASHed value.

        533 A  WRITE  IN  statement or interleave (c/) operation has
            produced a value requiring over 32 bits to represent.

        562 Insufficient data.

        579 Input data is invalid.

        621 The expression of a RESUME statement evaluated to #0.

        632 Program execution was terminated via a RESUME statement
            instead of GIVE UP.

        633 Execution has passed beyond the last statement  of  the
            program.

        774 A compiler error has occurred (see section ).

        778 An  unexplainable  compiler  error has occurred (see J.
            Lyon or D. Woods).






















       






                                  - 35 -



       _8_.  _J_C_L

       The information contained in the following  section  applies
       only to the Princeton compiler, run under OS/360.

       _8_._1  _T_h_e _P_r_i_n_c_e_t_o_n _C_o_m_p_i_l_e_r

       The  Princeton  compiler,  written  in SPITBOL (a variant of
       SNOBOL), performs the compilation in two stages.  First  the
       INTERCAL  source  is converted into SPITBOL source, then the
       latter is compiled and executed.

       It should be noted that  the  Princeton  compiler  fails  to
       properly interpret certain multiply-subscripted expressions,
       such as:

               ",1SUB",2SUB#1"#2"

       This  is  not  a  "bug".  Being  documented,  it is merely a
       "restriction". Such cases may  be  resolved  by  alternating
       sparks and ears in various levels of expression nesting:

               ",1SUB',2SUB#1'#2"

       which  is  advisable in any case, since INTERCAL expressions
       are unreadable enough as is.

       Since  there  is  currently  no  catalogued  procedure   for
       invoking  the  compiler,  the  user must include the in-line
       procedure  shown  in  Figure  3  in  his  job   before   the
       compilation  step.  Copies  of this in-line procedure may be
       obtained at any keypunch if the proper keys are struck.

       The compiler is then executed in the usual manner:


               // EXEC INTERCAL[,PARM='parameters']
               //COMPILE.SYSIN DD *
               {INTERCAL source deck}
               /*
               //EXECUTE.SYSWRITE DD *
               {input data}
               /*


       The various parameters are described following  the  in-line
       procedure.  At most one parameter from each set may apply to
       a given compilation; if more than  one  are  specified,  the
       results  are  undefined,  and  may  vary  depending upon the
       particular  set  of  options.  The  default  parameters  are
       underlined.




       






                                  - 36 -



               //INTERCAL PROC
               //COMPILE EXEC PGM=INTERCAL
               //STEPLIB DD DSN=U.INTERCAL.LIBRARY,DISP=SHR
               //             DD DSN=SYS1.FORTLIB,DISP=SHR
               //SYSPRINT DD SYSOUT=A,DCB=(BLKSIZE=992,LRECL=137,RECFM=VBA)
               //SYSPUNCH DD DUMMY
               //SCRATCH DD DSN=&COMPSET,UNIT=SYSDA,SPACE=(CYL,(3,1)),DISP=(,PASS)
               //EXECUTE EXEC PGM=EXECUTE,COND=(4,LT)
               //SOURCES DD DSN=U.INTERCAL.SOURCES,DISP=SHR   [4]
               //STEPLIB DD DSN=U.INTERCAL.LIBRARY,DISP=SHR
               //             DD DSN=SYS5.SPITLIB,DISP=SHR
               //             DD DSN=SYS1.FORTLIB,DISP=SHR
               //SYSIN DD DSN=&COMPSET,DISP=(OLD,DELETE)
               //SYSOBJ DD SYSOUT=B,DCB=(BLKSIZE=80,LRECL=80,RECFM=F)
               //SYSPRINT DD SYSOUT=A,DCB=(BLKSIZE=992,LRECL=137,RECFM=VBA)
               //SYSPUNCH DD DUMMY
               // PEND

             Figure 3.  Inline procedure for using INTERCAL.

       _O_P_T
       NOOPT
            In the default mode, the compiler will print a list  of
            all  options  in  effect,  including  the  defaults for
            unspecified parameter groups and the  effective  option
            for  those  sets  where  one was specified. If NOOPT is
            requested, it causes the default mode to be assumed.

       _O_P_T_S_U_B
       NOOPTSUB
       NOSUB
            Unless 'NOOPTSUB' is requested, the System  Library  is
            optimized,  resulting  in much more rapid processing of
            function calls. Specifying  NOOPTSUB  causes  the  non-
            optimized INTERCAL code shown in section
             to  be  used,  whereas  NOSUB requests that the System
            Library be omitted altogether.

       IAMBIC
       _P_R_O_S_E
            The IAMBIC parameter  permits  the  programmer  to  use
            poetic  license  and thus write in verse. If the reader
            does  not  believe  it  possible  to  write  verse   in

       ____________________

       4. Pending  acquisition  of SPITBOL release 3.0, the SOURCES
          DD card must be replaced by the five cards:

                  //NOOPTPFX DD DSN=U.INTERCAL.SOURCES(NOOPTPFX),DISP=SHR
                  //NOOPTSUB DD DSN=U.INTERCAL.SOURCES(NOOPTSUB),DISP=SHR
                  //OPTPFX DD DSN=U.INTERCAL.SOURCES(OPTPFX),DISP=SHR
                  //OPTSUB DD DSN=U.INTERCAL.SOURCES(OPTSUB),DISP=SHR
                  //PRELIM DD DSN=U.INTERCAL.SOURCES(PRELIM),DISP=SHR








                                  - 37 -



            INTERCAL,  he  should send the authors a stamped, self-
            addressed envelope, along with  any  INTERCAL  program,
            and they will provide one which is verse.

       _F_O_R_M_A_T
       NOFORMAT
            In  FORMAT  mode,  each  statement  printed is put on a
            separate line (or lines). In NOFORMAT mode,  the  free-
            format  source  is  printed  exactly as input.  In this
            latter case, statement numbers are  provided  only  for
            the  first  statement  on  a card, and they may be only
            approximate. Also, unrecognizable  statements  are  not
            flagged.

       SEQ
       _N_O_S_E_Q
            If  the  source deck has sequence numbers in columns 73
            through 80, specifying 'SEQ'  will  cause  them  to  be
            ignored.

       SOURCE
       _N_O_S_O_U_R_C_E
            If   NOSOURCE   is  selected,  all  source  listing  is
            suppressed.

       LIST
       _N_O_L_I_S_T
            If LIST is specified, the compiler will provide a  list
            of  statement  numbers  catalogued according to type of
            statement. The compiler  uses  this  table  to  perform
            abstentions by gerund.

       WIDTH=nn
            This  sets  the  width (in number of characters) of the
            output line for FORMAT mode output. The default is 113322..

       CODE
       _N_O_C_O_D_E
            Include 'CODE'  in  the  parameter  list  to  obtain  a
            listing  of the SPITBOL code produced for each INTERCAL
            statement.

       LINES=nn
            This determines the number of lines  per  page,  during
            both compilation and execution. The default is 6600..

       DECK
       _N_O_D_E_C_K
            Selecting 'DECK' will cause the compiler to punch out a
            SPITBOL  object  deck  which  may  then  be run without
            reinvoking the INTERCAL (or SPITBOL) compiler.

       _K_I_D_D_I_N_G


       






                                  - 38 -



       NOKIDDING
            Select NOKIDDING to eliminate the snide  remarks  which
            ordinarily accompany INTERCAL error messages.

       _G_O
       NOGO
            Specifying   'NOGO'  will  cause   the  program  to  be
            compiled but not  executed.  EXECUTE/NOEXECUTE  may  be
            substituted  for  GO/NOGO,  but  this will result in an
            error, and GO will be assumed.

       _B_U_G
       NOBUG
            Under the default, there is a fixed  probability  of  a
            fatal  compiler  bug  being  worked  at random into the
            program being compiled. Encountering  this  bug  during
            execution  results in error message 774 (see section ).
            This probability is reduced to zero under 'NOBUG'. This
            does not affect the probability (presumably negligible)
            of error message 778.

       _8_._2  _O_t_h_e_r _I_N_T_E_R_C_A_L _C_o_m_p_i_l_e_r_s

       There are no other INTERCAL compilers. [5]

























       ____________________

       5. This assertion in the INTERCAL-72  manual  was  blatantly
          contradicted  by  some  notes  on an Atari implementation
          included at the  end  of  the  manual.   So,  you  expect
          compiler manuals to be consistent?







                                  - 39 -



                               TTOONNSSIILL AA[[66]]




       The Official INTERCAL Character Set

       Tabulated next are all  the  characters  used  in  INTERCAL,
       excepting  letters  and  digits,  along with their names and
       interpretations. Also included are  several  characters  not
       used  in  INTERCAL, which are presented for completeness and
       to allow for future expansion.




































       ____________________

       6. Since all other reference manuals have Appendices, it was
          decided  that  the  INTERCAL  manual  should contain some
          other type of removable organ.

       7. This footnote intentionally unreferenced.







                                  - 40 -



       +----------------------------------------------------------------------------+
       | Character   Name                                Use (if any)               |
       +----------------------------------------------------------------------------+
       | .           spot                                identify 16-bit variable   |
       | :           two-spot                            identify 32-bit variable   |
       | ,           tail                                identify 16-bit array      |
       | ;           hybrid                              identify 32-bit array      |
       | #           mesh                                identify constant          |
       | =           half-mesh                                                      |
       | '           spark                               grouper                    |
       | `           backspark                                                      |
       | !           wow                                 equivalent to spark-spot   |
       | ?           what                                _u_n_a_r_y _e_x_c_l_u_s_i_v_e _O_R _(_A_S_C_I_I_) |
       | "           rabbit-ears                         grouper                    |
       | ".           rabbit                              equivalent to ears-spot    |
       | |           spike                                                          |
       | %           double-oh-seven                     percentage qualifier       |
       | -           worm                                used with angles           |
       | <           angle                               used with worms            |
       | >           right angle                                                    |
       | (           wax                                 precedes line label        |
       | )           wane                                follows line label         |
       | [           U turn                                                         |
       | ]           U turn back                                                    |
       | {           embrace                                                        |
       | }           bracelet                                                       |
       | *           splat                               flags invalid statements   |
       | &           ampersand [9]                       unary logical AND          |
       | V           V (or book)                         unary logical OR           |
       | V-           bookworm (or universal qualifier)   unary exclusive OR         |
       | $           big money                           _b_i_n_a_r_y _m_i_n_g_l_e _(_A_S_C_I_I_)      |
       | c/           change                              binary mingle              |
       | ~           sqiggle                             binary select              |
       | _           flat worm                                                      |
       | -           overline                            indicates "times 1000"     |
       | +           intersection                        separates list items       |
       | /           slat                                                           |
       | \           backslat                                                       |
       | @           whirlpool                                                      |
       |             hookworm                                                       |
       | ^           shark (or simply sharkfin)                                     |
       | #*[]          blotch                                                         |
       +----------------------------------------------------------------------------+
               Table 2 (top view). INTERCAL character set.








       ____________________

       9. Got any better ideas?







                                  - 41 -



                                 TTOONNSSIILL BB


                    NNOOTTEESS OONN TTHHEE AATTAARRII IIMMPPLLEEMMEENNTTAATTIIOONN




       The  Atari  implementation  of  INTERCAL  differs  from  the
       original  Princeton  version  primarily  in the use of ASCII
       rather than EBCDIC. Since there is no "change" sign  (c/)  in
       ASCII, we have substituted the "big money" ($) as the mingle
       operator.   We  feel  that  this  correctly  represents  the
       increasing  cost  of  software  in  relation  to   hardware.
       (Consider that in 1970 one could get RUNOFF for free, to run
       on  a  $20K  machine,  whereas today a not quite as powerful
       formatter costs $99 and runs on a $75 machine.) We also feel
       that there should be no defensible contention that  INTERCAL
       has  any  sense.   Also,  since overpunches are difficult to
       read on the average VDT, the exclusive-or  operator  may  be
       written  ?.  This  correctly  expresses the average person's
       reaction on first encountering exclusive-or, especially on a
       PDP-11. Note that in both of these cases,  the  over-punched
       symbol  may also be used if one is masochistic, or concerned
       with portability to  the  Princeton  compiler.  The  correct
       over-punch  for  "change" is "c<backspace>/" and the correct
       over-punch for V- is "V<backspace>-".  These  codes  will  be
       properly  printed  if  you  have  a  proper printer, and the
       corresponding EBCDIC code  will  be  produced  by  the  /IBM
       option on the LIST command.

























       



