# ‘headache‘

### Vincent Simonet

### November, 2002

This manual is also available in plain text, PostScript and PDF.

## 1 Overview

It is a common usage to put at the beginning of source code files a short header giving, for instance, some copyright informations. ‘headache‘ is a simple and lightweight tool for managing easily these headers. Among its functionalities, one may mention:

- Headers must generally be generated as comments in source code files. ‘headache‘ deals with different file types and generates for each of them headers in an appropriate format.
- ‘headache‘ automatically detects existing headers and removes them. Thus, you can use it to update headers in a set of files.

‘headache‘ is distributed under the terms of the GNU Library General Public License. See file ‘LICENSE‘ of the distribution for more information.

## 2 Compilation and installation

Building ‘headache‘ requires Objective Caml (available at http://caml.inria.fr/) and GNU Make. In addition, from version 1.03-utf8, the build requires the Unicode library Camomile and, from version 1.04, Dune.

#### Instructions

‘headache‘ is available through OPAM (available at http://opam.ocaml.org/), the OCaml Package Manager. This is the preferred installation method. Then the following sequence of commands should install the package:

      opam init
      opam install headache

Alternatively, you can use these commands (Dune must be installed):

      make && sudo make INSTALLDIR=/usr/local/bin install

Build the executable and install it into the specified directory.

## 3 Usage

Let us illustrate the use of this tool with a small example. Assume you have a small project mixing C and Caml code consisting in three files ‘foo.c‘, ‘bar.ml‘ and ‘bar.mli‘, and you want to equip them with some header. First of all, write a header file, i.e. a plain text file including the information headers must mention. An example of such a file is given in figure 1. In the following, we assume this file is named ‘myheader‘ and is in the same directory as source files.

Then, in order to generate headers, just run the command:

      headache -h myheader foo.c bar.ml bar.mli

Each file is equipped with a header including the text given in the header file ‘myheader‘, surrounded by some extra characters depending on its format making it a comment (e.g. ‘(*‘ and ‘*)‘ in ‘.ml‘ files). If you update informations in the header file ‘myheader‘, you simply need to re-run the above command to update headers in source code files: existing ones are automatically removed.

Similarly, running:

      headache -r foo.c bar.ml bar.mli

removes any existing in files ‘foo.c‘, ‘bar.ml‘ and ‘bar.mli‘. Files which do not have a header are kept unchanged.

The current headers of files can be extracted:

      headache -e foo.c bar.ml bar.mli

prints on the standard output the current headers of the files ‘foo.c‘, ‘bar.ml‘ and ‘bar.mli‘. All files are kept unchanged.

>                                  Headache
>                    Automatic generation of files headers

>             Vincent Simonet, Projet Cristal, INRIA Rocquencourt

>     Copyright 2002
>     Institut National de Recherche en Informatique et en Automatique.
>     All rights reserved.  This file is distributed under the terms of
>     the GNU Library General Public License.

>     Vincent.Simonet@inria.fr           http://cristal.inria.fr/~simonet/

> Figure 1: An example of header file

## 4 Configuration file

File types and format of header may be specified by a configuration file. By default, the default builtin configuration file given in figure 2 is used. You can also use your own configuration file thanks to the ‘-c‘ option:

      headache -c myconfig -h myheader foo.c bar.ml bar.mli

In order to write your own configuration, you can follow the example given in figure 2. A configuration file consists in a list of entries separated by the character ‘|‘. Each of them is made of two parts separated by an ‘->‘:

- The first one is a regular expression. Regular expression are enclosed within double quotes and have the same syntax as in Gnu Emacs. ‘headache‘ determines file types according to file basenames; thus, each file is dealt with using the first line its name matches.
- The second one describes the format of headers for files of this type. It consists of the name of a model (e.g. ‘frame‘), possibly followed by a list of arguments. Arguments are named: ‘open:"(*"‘ means that the value of the argument ‘open‘ is ‘(*‘.

‘headache‘ currently supports three models:

- ‘frame‘. With this model, headers are generated in a frame. This model requires three arguments: ‘open‘ and ‘close‘ (the opening and closing sequences for comments) and ‘line‘ (the character used to make the horizontal lines of the frame). Two optional arguments may be used: ‘margin‘ (a string printed between the left and right side of the frame and the border, by default two spaces) and ‘width‘ (the width of the inside of the frame, default is 68).
- ‘lines‘. Headers are typeset between two lines. Three arguments must be provided: ‘open‘ and ‘close‘ (the opening and closing sequences for comments), ‘line‘ (the character used to make the horizontal lines). Three optional arguments are allowed: ‘begin‘ (a string typeset at the beginning of each line, by default two spaces), ‘last‘ (a string typeset at the beginning of the last line) and ‘width‘ (the width of the lines, default is 70).
- ‘no‘. This model generates no header and has no argument.

It is possible to change the default builtin configuration file at compile time. For this, just edit the file ‘config_builtin.txt‘ present in the source distribution before building the software.

>     # Objective Caml source
>       ".*\\.ml[il]?" -> frame open:"(*" line:"*" close:"*)"
>     | ".*\\.fml[i]?" -> frame open:"(*" line:"*" close:"*)"
>     | ".*\\.mly"     -> frame open:"/*" line:"*" close:"*/"
>     # C source
>     | ".*\\.[chy]"    -> frame open:"/*" line:"*" close:"*/"
>     # Latex
>     | ".*\\.tex"     -> frame open:"%"  line:"%" close:"%"
>     # Misc
>     | ".*Makefile.*" -> frame open:"#"  line:"#" close:"#"
>     | ".*README.*"   -> frame open:"*"  line:"*" close:"*"
>     | ".*LICENSE.*"  -> frame open:"*"  line:"*" close:"*"

> Figure 2: The default builtin configuration file

It is also possible to add entries into your own configuration file that specify when the initial lines of the processed file have to be skipped. As previously, these entries are separated by the character ‘|‘ and each of them is made of two parts separated by an ‘->‘:

- Again, the first part is a regular expression used by ‘headache‘ to determine the file type. But here, it is according to its full filename (including the pathname).
- The second part specifies when the initial lines must be skipped. It consists of the keyword ‘skip‘ followed by one of the named arguments ‘multiline_match:‘ or ‘match:‘, then a regular expression. As long as the lines match a ‘multiline_match‘ parameter, ‘headache‘ skips them and checks the next line. If the current line matches only a ‘match‘ parameter, ‘headache‘ skips the current line and breaks the iteration there (of course, if nothing matches, ‘headache‘ puts the header before the current line).

>     # Script file
>      | ".*\\.sh" -> frame open:"#"  line:"#" close:"#"
>      | ".*\\.sh" -> skip match:"#!.*"

> Figure 3: Example of a configuration file for skipping the shebang line of shell scripts

Figure 3 shows an example of configuration file that can used to skip the shebang line of shell scripts: when the first line of ‘.sh‘ files starts with ‘#!‘, ‘headache‘ does not modify that line and considers that the header must start at the second line.

>     # SWI Prolog file
>      | ".*\\.pl" -> frame open:"%"  line:"%" close:"%"
>      | ".*\\.pl" -> skip multiline_match:"#!.*" multiline_match:":-.*"

> Figure 4: Example of a configuration file for skipping the shebang line, as well as lines containing Prolog directives, such as Unicode usage.

Figure 4 shows an example of configuration file that can used for ‘SWI prolog‘ files: for a ‘.pl‘ file starting with the following three first lines, ‘headache‘ considers that the header must start just after the first two lines:

      #!/usr/bin/env swipl
      :- encoding(utf8).
      % remainder of the file, that can be after the header

> This document was translated from LATEX by H E V E A.