FILEPP(1)

NAME
filepp - A generic file preprocessor

SYNOPSIS
filepp [options] filename(s)

DESCRIPTION
filepp is a generic file preprocessor designed to allow the functionality provided by the C preprocessor cpp(1) to be used with any file type. filepp is designed to be easily customised and extended.

OPTIONS
filepp accepts the following command line options:

-b  Suppress blank lines originating from include files (this has no effect on the top-level file).

-c  Read input from STDIN instead of a file. Note: if both -c and input files are specified, both are used as inputs in the order given.

-Dmacro
    Predefine macro to have a definition of `1'.

-Dmacro=defn
    Predefine macro to have a definition of defn.

-d  Output debugging information.

-dd Output verbose debugging information. This option shows all normal debugging information, plus the full list of defined macros every time the list changes.

-e  Define all environment variables as macros with prefix envchar.

-ec char
    Set envchar (prefix of environment variables defined as macros) to char, defaults to $. (Note: this option only takes effect at the time the environment variables are converted to macros).

-ecn
    Set envchar (prefix of environment variables defined as macros) to nothing (no prefix).

-h  Show summary of options.

-Idir
    Append directory dir to the list of directories searched for include files.

-k  Turn off parsing of all keywords. This is useful if you just want to use the macro expansion facilities of filepp. With this option all keywords found will be ignored, filepp will just replace any macros specified with the -Dmacro=defn option.

-kc char
    Set keyword prefix character to char (can also be a string). All filepp keywords are prefixed with the character # by default. This option allows the prefix to be changed to something else.

-lc char
    Set line continuation character to char (can also be a string). When the line continuation character is found with a newline following it, it and the newline are replaced by the line continuation replacement character. Default is \ (cpp(1) style).

-lr char
    Set line continuation replacement character to char (can also be a string). Default is a null string (cpp(1) style).

-lrn
    Set line continuation replacement character to be a newline.

-m module.pm
    Load module module.pm. module.pm is a perl(1) module which can be used to extend or modify the behaviour of filepp. See section FILEPP MODULES for details of modules included with filepp and FILEPP MODULE API for details on how to write your own modules.

-Mdir
    Append directory dir to the list of directories searched for filepp modules. This list defaults to the directory the filepp modules are installed (if any) plus the default Perl module paths. (Note: this adds the directory to the Perl @INC list.)

-o name
    Write output to name instead of STDOUT. If there is only one input file and it has the same name as the output file, the original input file will be backed-up as name~.

-re Treat keyword prefix character and line continuation character as Perl regular expressions instead of normal strings.

-s  Run filepp in safe mode. This turns off the pragma keyword.

-u  Undefine all currently defined macros, including predefined ones.

-v  Show version of program.

-w  Turn on word boundaries when replacing macros. When word boundaries are on, macros will only be replaced if the macro appears in the text as a word. For example, by default macro would be replaced in both cases of the following text: macro as word, macroNOTaword but only the first occurrence would be replaced with the -w option. With this option enabled filepp will only replace macros which contain alphanumeric characters. International (non-ASCII) character sets can be supported using Perl's locale handling.

KEYWORDS
filepp supports the following keywords:

#include <FILE>
    Include a file in the file being processed. This variant is used for "system" include files. It searches for a file named FILE in a list of directories specified by you. Directories are specified with the command option `-I'. filepp does not predefine any system directories in which to search for files.

#include "FILE"
    Include a file in the file being processed. This variant is used for include files of your own project. It searches for a file named FILE first in the current directory, then in the list of directories specified with the command option `-I'. The current directory is the directory the base input file is in.

#define macro
    Define the macro macro to have a definition of `1'. macro can then be used with the keywords #ifdef and #ifndef.

#define macro defn
    Define the macro macro to have the value defn. macro can then be used with the keywords #ifdef and #ifndef. Also, all instances of macro following the #define statement will be replaced with the string defn. The string defn is taken to be all the characters on the line following macro.

#define macro(arg1, arg2, ...) defn
    Define the macro macro to have the value defn with arguments (arg1, arg2, ...). macro can be used as follows: #define macro(foo) defn with foo in Now when replacing occurs: macro(bar) will become: defn with bar in Macros can have any number of comma separated arguments.

#if expr
    A conditional statement, expr will be evaluated to true (1) or false (0). If expr evaluates to true, the text between the #if and the next #else or #endif will be included. If expr evaluates to false, the text between the #if and the next #else or #endif will be ignored. expr can use all the usual cpp style comparisons (==, !=, <, >, etc.). Multiple comparisons can be combined with and (&&) and or (||). The defined keyword can also be used to check if macros are defined. For example: #if defined macro && macro == defn (Note to filepp experts: #if works by first parsing expr for the defined keyword and checking if the macro it refers to is defined, replacing it with 1 if it is and 0 if it isn't. It then checks expr for any other macros and replaces them with their definition. Finally it passes expr through Perl's eval function, which returns true or false.)

#elif expr
    #elif stands for "else if". Like #else, it goes in the middle of a #if[n][def]-#endif pair and subdivides it; it does not require a matching #endif of its own. Like #if, the #elif directive includes an expression to be tested.

#ifdef macro
    A conditional statement, if macro has been defined the text between the #ifdef and the next #else or #endif will be included. If macro has not been defined the text between the #ifdef and the next #else or #endif will be ignored.

#ifndef macro
    The reverse case of the #ifdef conditional.

#else
    The #else directive can be added to a conditional to provide alternative text to be used if the condition is false.

#endif
    Used to terminate a conditional statement. Normal processing resumes following the #endif.

#undef macro
    Undefine a previously defined macro.

#error mesg
    Causes filepp to exit with the error message mesg.

#warning mesg
    Causes filepp to issue the warning message mesg.

#comment mesg
    As filepp is supposed to be a generic file preprocessor, it cannot support any known comment styles, therefore it defines its own with this keyword. All lines starting with #comment are treated as comments and removed by filepp.

#pragma filepp function arg1, arg2, ...
    The #pragma keyword immediately followed by the word filepp allows the user to execute a Perl function during parsing. The word immediately following filepp is taken as the name of the function and the remainder of the line is taken to be a comma separated list of arguments to the function. Any of the filepp internal functions (see section FILEPP MODULE API) can be called with the #pragma keyword. Warning: There are obvious security risks with allowing arbitrary functions to be run, so the -s (safe mode) command line option has been added which turns the #pragma keyword off.

PREDEFINED MACROS
filepp supports a set of predefined macros. All the predefined macros are of the form __MACRO__, where MACRO is:

FILE
    This macro expands to the name of the current input file.

LINE
    This macro expands to the current input line number.

DATE
    This macro expands to a string that describes the date on which the preprocessor is being run. The string contains eleven characters and looks like "Jun 08 2001".

ISO_DATE
    This macro expands to a string that describes the date on which the preprocessor is being run. The string is in the format specified by ISO 8601 (YYYY-MM-DD) and looks like "2001-06-08".

TIME
    This macro expands to a string that describes the time at which the preprocessor is being run. The string contains eight characters and looks like "10:51:39".

BASE_FILE
    This macro expands to the name of the main input file.

INCLUDE_LEVEL
    This macro expands to a decimal integer constant that represents the depth of nesting in include files. The value of this macro is incremented on every #include directive and decremented at every end of file.

NEWLINE
    This macro expands to a newline.

TAB This macro expands to a tab.

NULL
    This macro expands to nothing. It is useful if you want to define something to be nothing.

VERSION
    This macro expands to a string constant which describes the version number of filepp. The string is a sequence of decimal numbers separated by periods and looks like "1.3.0".

FILEPP_INPUT
    This macro expands to a string constant which says the file was generated automatically from the current BASE_FILE and looks like "Generated automatically from filepp.1.in by filepp".

FILEPP MODULES
The following modules are included with the main filepp distribution:

FOR MODULE - for.pm
The for module implements a simple for loop. Its file name is for.pm.

The for loop is similar in functionality to that of other programming languages such as Perl or or C. It has a single variable (a filepp macro) which is assigned a numerical value. This numerical value changes by a set increment on each iteration through the loop. The loop termiates when the value no longer passes a comparison test.

The for module implements the following keywords:

#for macro start compare end increment
    The #for keyword is functionally equivalent to the following Perl or C style loop: for(macro=start; macro compare end; macro+=increment) The #for keyword requires the following space separated parameters: macro : The name of the macro to which the for loop should assign its numerical value. start : The value macro should be assigned at the start of the loop. start should be a numerical value. compare : The comparison to make between the current value of macro and the value end to determine when the loop should terminate. Valid values for compare are <, >, >=, <=. end : the for loop will terminate when the test
      macro compare end fails. end should be a numerical value. increment : The value to increment macro on each iteration of the loop. At the end of each iteration the value of increment is added to the current value of macro. increment should be a numerical value.

#endfor
    The #endfor keyword is used to signify the end of the loop. Everything within the opening #for and the closing #endfor will be processed on each iteration of the loop.

Example usage: #for COUNTER 10 > 1 -2.5
  COUNTER #endfor In the above example COUNTER will be defined to have values 10, 7.5, 5 and 2.5 for each successive iteration through the loop. Nested loops are also possible, as is changing the value of the macro within the loop. start, end and increment should all be numerical values, however it is possible to use macros instead provided the macros are defined to have numerical values.

LITERAL MODULE - literal.pm
The literal module prevents macros appearing in literal strings from being replaced. A literal string is defined as having the form: "literal string with macro in" In the above example, macro will not be replaced. The behaviour of the literal module can be reveresed by defining the macro LITERAL_REVERSE before loading the module, for example: filepp -DLITERAL_REVERSE -m literal.pm <files> This has the effect of only replacing macros which appear in strings.

TOUPPER MODULE - toupper.pm
The toupper module converts all lowercase letters to uppercase.

TOLOWER MODULE - tolower.pm
The tolower module converts all uppercase letters to lowercase.

C/C++ COMMENT MODULE - c-comment.pm
The c-comment module removes all C style: /* comment */ and C++ style: // comment comments from a file.

HASH COMMENT MODULE - hash-comment.pm
The hash-comment module removes all comments of the style: # comment from a file. This is the commenting style used by Perl, Bourne Shell, C Shell and many other programs and configuration files. Hash comments are removed after keywords have been processed.

FILEPP MODULE API
The behaviour of filepp can be modified or extended through the use of modules. filepp modules are in fact perl(1) modules, and the rest of this section assumes the reader has a knowledge of Perl. filepp modules are perl(1) modules which extend or modify filepp's behaviour by either calling or replacing filepp's internal functions. filepp has the Perl package name Filepp so its internal functions can be called within modules either as Filepp::function() or just function(). Any of filepp's internal functions can be called or replaced from within a filepp module, the most useful ones are:

Debug($string)
    Print $string as debugging information if debugging is enabled.

AddProcessor($function)
    Allows the module to add a function to filepp's processing chain. The processing chain is a set of functions which are ran on each line of a file as it is processed. The default function in the processing chain is the ReplaceDefines() function which does macro replacement. Further functions can be added to the chain, with each function taking a string (the current line) as input and returning the processed string as output. The order the functions are run is: most recently added first.

RemoveProcessor($function)
    Removes the processor function $function from the processing chain.

$string=ReplaceDefines($string)
    Replaces all macros in $string with their definitions and returns the processed string.

AddKeyword($string,$function)
    Add the keyword named $string. When the keyword is found in text processing the function named $function will be run with everything following the keyword passed as a single argument.

RemoveKeyword($string)
    Removes the keyword named $string.

RemoveAllKeywords()
    Removes all the keywords currently defined for filepp (used for the -k command line option).

AddIfword($string)
    Adds keyword named $string to Ifword list. An Ifword takes in the string following the keyword and optionally parses it, returning a 1 if the string parses to true and 0 for false. The default Ifwords are if, ifdef and ifndef.

RemoveIfword($string)
    Removes keyword named $string from Ifword list (note: this does NOT remove the keyword, use RemoveKeyword for that).

AddElseword($string)
    Adds keyword named $string to Elseword list. An Elseword takes in the string following the keyword and optionally parses it, returning a 1 if the string parses to true and 0 for false. The default Elsewords are else and elif.

RemoveElseword($string)
    Removes keyword named $string from Elseword list.

AddEndifword($string)
    Adds keyword named $string to Endifword list. An Endifword should return a 1 to indicate successful termination of the if block. If the Endifword returns 0 the Endifword is ignored and filepp assumes the current if block carries on after the Endifword. The default Endifword is endif.

RemoveEndifword($string)
    Removes keyword named $string from Endifword list.

AddIncludePath($string)
    Adds the include path $string to the list of directories to search for include files (used for the -I command line option).

AddModulePath($string)
    Adds the path $string to the list of directories to search for filepp modules (used for the -M command line option).

AddInputFile($string)
    Adds another input file to the list of files to be processed (used for adding input files at the command line).

ChangeOutputFile($string)
    Closes the current output file and attempts to open a new one named $string.

SetKeywordchar($string)
    Set the initial keyword char to $string (used for the -kc command line option).

SetContchar($string)
    Set the line continuation char to $string (used for the -lc command line option).

SetContrepchar($string)
    Set the line continuation replacement char to $string (used for the -lr command line option).

SetBlankSupp(1/0)
    Turns blank-line suppression on/off (1 = suppress, 0 = don't suppress). When blank-line suppression is on, blank lines in input files will not be copied to the output. Unlike the corresponding command-line option (-b), this function can also have effect in the top-level file. The setting of blank-line suppression applies to the current file being processed and all files included in the current file.

ResetBlankSupp()
    Resets blank-line suppression to the command-line specified value. This only affects the output of blank lines from the current file being processed and all files included in the current file. In the top-level file, this always turns blank-line suppression off.

SetEatTrail($string)
    If $string is a macro, whenever the macro is replaced all blank space between the macro's replacement and the next character on the line will be eaten. For example, if macro foo is defined to bar and foo has been set to have it's trail eaten, the following:
     eat my foo trail is replaced with
     eat my bartrail

CheckEatTrail($string)
    Returns 1 if macro $string will have it's tail eaten, 0 otherwise.

SetEnvchar($string)
    Set the prefix of environment variables converted to macros (envchar) to $string (used for -ec and -ecn command line options).

DefineEnv()
    Define all environment variables as macros with prefix envchar (used for -e command line option).

SetOutput(1/0)
    Turns writing of parsed input file to output file on/off. This takes either 1 (output on) or 0 (output off) as input. When the output is turned off, the only output produced from filepp will be that generated by the module.

SetWordBoundaries(1/0)
    Turns on(1) or off(0) word boundary checking when replacing macros (used for the -w command line option).

SetCharPerlre(1/0)
    Turns on(1) or off(0) allowing of keyword prefix char and line continuation char to be Perl regular expressions (used for the -re command line option).

UndefAll()
    Undefines all currently defined macros, including predefined ones (used for the -u command line option).

UseModule($string)
    Loads a perl(1) module named $string using the Perl command require (used for the -m command line option).

$string=GetNextLine()
    Returns the next line (after line continuation has been dealt with) of the input file currently being processed. Returns NULL for end of file.

Write($string)
    Writes $string to the current output file.

In addition all the standard filepp keywords have equivalent functions which optionally take a single argument. The functions have the same name as the keyword, only with a capital first letter (eg: #define string calls the function Define(string)). A full description of the Parse function and all the other filepp internal functions is beyond the scope of this man page. The filepp script is well commented and hopefully readable by a Perl programmer, so use the source Luke!

BUGS
filepp has no known bugs, only "features". If you find any "features", please report them to the author.

COPYING
Copyright (C) 2000-2001 Darren Miller

filepp is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version.

This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.

You should have received a copy of the GNU General Public License along with this program; see the file COPYING. If not, write to the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.

SEE ALSO
cpp(1), perl(1)

AUTHOR
Darren Miller <darren@cabaret.demon.co.uk>.