NAME¶

preprocess - Preprocess a file.

SYNOPSIS¶

preprocess [options...] infile

DESCRIPTION¶

Preprocess is like a typical C preprocessor, but it extends to multiple languages. Languages for which it works include: C++, Python, Perl, Tcl, XML, JavaScript, CSS, IDL, TeX, Fortran, PHP, Java, Shell scripts (Bash, CSH, etc.) and C#. Preprocess is usable both as a command line app and as a Python module.

OPTIONS¶

-h, --help

Print help text and exit.

-V, --version

Print the version info and exit.

-v, --verbose

Give verbose output for errors.

-o outfile

Write output to the given file instead of to stdout.

-f, --force

Overwrite given output file. Otherwise an IOError will be raised if outfile already exists.

-D define

Define a variable for preprocessing. define can simply be a variable name (in which case it will be true) or it can be of the form var= val. An attempt will be made to convert val to an integer so " -D FOO=0" will create a false value.

-I dir

Add a directory to the include path for #include directives.

-k, --keep-lines

Emit empty lines for preprocessor statement lines and skipped output lines. This allows line numbers to stay constant.

-s, --substitute

Substitute defines into emitted lines. By default substitution is NOT done because it currently will substitute into program strings.

MODULE USAGE¶

from preprocess import preprocess
preprocess(infile, outfile=sys.stdout, defines={}, force=0,
keepLines=0, includePath=[], substitute=0)

The <infile> can be marked up with special preprocessor statement lines of the form:

<comment-prefix> <preprocessor-statement> <comment-suffix>

where the <comment-prefix/suffix> are the native comment delimiters for that file type.

EXAMPLES¶

HTML (*.htm, *.html) or XML (*.xml, *.kpf, *.xul) files:

<!-- #if FOO -->
...
<!-- #endif -->

Python (*.py), Perl (*.pl), Tcl (*.tcl), Ruby (*.rb), Bash (*.sh), or make ([Mm]akefile*) files:

# #if defined('FAV_COLOR') and FAV_COLOR == "blue"
...
# #elif FAV_COLOR == "red"
...
# #else
...
# #endif

C (*.c, *.h), C++ (*.cpp, *.cxx, *.cc, *.h, *.hpp, *.hxx, *.hh), Java (*.java), PHP (*.php) or C# (*.cs) files:

// #define FAV_COLOR 'blue'
...
/* #ifndef FAV_COLOR */
...
// #endif

Fortran 77 (*.f) or 90/95 (*.f90) files:

C #if COEFF == 'var'
...
C #endif

PREPROCESSOR SYNTAX¶

Valid statements:

#define <var> [<value>]
#undef <var>
#ifdef <var>
#ifndef <var>
#if <expr>
#elif <expr>
#else
#endif
#error <error string>
#include "<file>"

where <expr> is any valid Python expression. The expression after #if/elif may be a Python statement. It is an error to refer to a variable that has not been defined by a -D option or by an in-content #define. Special built-in methods for expressions:

defined(varName) Return true if given variable is defined.

TIPS¶

A suggested file naming convention is to let input files to preprocess be of the form <basename>.p.<ext> and direct the output of preprocess to <basename>.<ext>, e.g.:

preprocess -o foo.py foo.p.py

The advantage is that other tools (esp. editors) will still recognize the unpreprocessed file as the original language.

AUTHORS¶

Trent Mick <trentm@gmail.com> This manual page was written by Johannes Ring <johannr@simula.no> for the Debian GNU/Linux system (but may be used by others).