### 13.5 Functions and Variables for Fortran Output

Option variable: fortindent

  Default value: `0`

  `fortindent` controls the left margin indentation of expressions printed out by the `fortran` command. `0` gives normal printout (i.e., 6 spaces), and positive values will causes the expressions to be printed farther to the right.

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  Categories: Translation and compilation

Function: fortran (expr)

  Prints expr as a Fortran statement. The output line is indented with spaces. If the line is too long, `fortran` prints continuation lines. `fortran` prints the exponentiation operator `^` as `**`, and prints a complex number `a + b %i` in the form `(a,b)`.

  expr may be an equation. If so, `fortran` prints an assignment statement, assigning the right-hand side of the equation to the left-hand side. In particular, if the right-hand side of expr is the name of a matrix, then `fortran` prints an assignment statement for each element of the matrix.

  If expr is not something recognized by `fortran`, the expression is printed in `grind` format without complaint. `fortran` does not know about lists, arrays, or functions.

  `fortindent` controls the left margin of the printed lines. `0` is the normal margin (i.e., indented 6 spaces). Increasing `fortindent` causes expressions to be printed further to the right.

  When `fortspaces` is `true`, `fortran` fills out each printed line with spaces to 80 columns.

  `fortran` evaluates its arguments; quoting an argument defeats evaluation. `fortran` always returns `done`.

  See also the function `f90` for printing one or more expressions as a Fortran 90 program.

  Examples:

      (%i1) expr: (a + b)^12$
      (%i2) fortran (expr);
            (b+a)**12
      (%o2)                         done
      (%i3) fortran ('x=expr);
            x = (b+a)**12
      (%o3)                         done
      (%i4) fortran ('x=expand (expr));
            x = b**12+12*a*b**11+66*a**2*b**10+220*a**3*b**9+495*a**4*b**8+792
           1   *a**5*b**7+924*a**6*b**6+792*a**7*b**5+495*a**8*b**4+220*a**9*b
           2   **3+66*a**10*b**2+12*a**11*b+a**12
      (%o4)                         done
      (%i5) fortran ('x=7+5*%i);
            x = (7,5)
      (%o5)                         done
      (%i6) fortran ('x=[1,2,3,4]);
            x = [1,2,3,4]
      (%o6)                         done
      (%i7) f(x) := x^2$
      (%i8) fortran (f);
            f
      (%o8)                         done

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  Categories: Translation and compilation

Option variable: fortspaces

  Default value: `false`

  When `fortspaces` is `true`, `fortran` fills out each printed line with spaces to 80 columns.

  ·

  Categories: Translation and compilation