Wordsplit - an enhanced word splitter

This package provides a set of C functions for parsing input strings. Default parsing rules are are similar to those used in Bourne shell. This includes tilde expansion, variable expansion, quote removal, word splitting, command substitution, and path expansion. Parsing is controlled by a number of settings which allow the caller to alter processing at each of these phases or even to disable any of them. Thus, wordsplit can be used for parsing inputs in different formats, from simple character-delimited entries, as in /etc/passwd, and up to complex shell statements.

The following code fragment shows the basic usage:

/* This variable controls parsing */
wordsplit_t ws;
int rc;

/* Provide variable definitions */
ws.ws_env = (const char **) environ;
/* Provide a function for expanding commands */
ws.ws_command = runcom;
/* Split input_string into words */
rc = wordsplit(input_string, &ws,
               WRDSF_QUOTE     /* Handle both single and double quoted strings as words. */
               | WRDSF_SQUEEZE_DELIMS /* Compress adjacent delimiters */
               | WRDSF_PATHEXPAND     /* Expand pathnames */
               | WRDSF_SHOWERR);      /* Show errors */
if (rc == 0) {
    /* Success.  The resulting words are returned in the NULL-terminated
       array ws.ws_wordv.  Number of words is in ws.ws_wordc */
}
/* Reclaim the allocated memory */
wordsplit_free(&ws);

For a detailed discussion, please see the man page wordsplit(3) included in the package.

The package is designed as a drop-in facility for use in larger programs. It consists of the following files:

wordsplit.h

Interface header.

wordsplit.c

Main source file.

wordsplit.3

Manual page.

For most uses, you will need only these three. The rest of files are for building the autotest-based testsuite:

wsp.c

Auxiliary test program.

wordsplit.at

The source for the testsuite.

The project is designed to be used as a git submodule. To incorporate it into your project, first select the location for the wordsplit directory within your project. Then add the submodule at this location. The rest is quite straightforward: you need to add wordsplit.c to your sources and add both wordsplit.c and wordsplit.h to the distributed files.

The following will describe each step in detail. For the rest of this discussion it is supposed that wordsplit is the name of the location selected for the submodule. It is also supposed that your project uses GNU autotools framework. If you are using plain makefiles, these instructions are easy to convert to such use as well.

To add the submodule do:

git submodule add git://git.gnu.org.ua/wordsplit.git wordsplit

There are two methods of including the sources to the project: direct incorporation and incorporation via VPATH.

The package contains two files for building the testsuite: wsp.c, which is used to build the auxiliary binary wsp, and wordsplit.at, which can be included to a GNU autotest-based testsuite source.

The discussion below is for those who wish to include wordsplit testsuite into their project. It assumes that the hosting project already has an autotest-based testsuite.

First version of wordsplit appeared in March 2009 as a part of the Wydawca¹ project. Its main usage was to assist in configuration file parsing. The parser subsystem proved to be quite useful and soon evolved into a separate project - Grecs². Wordsplit had since been used (as a git submodule) in a number of other projects, such as GNU Dico³ and Direvent⁴, to name a few.

In 2010 the wordsplit sources were incorporated to the GNU Mailutils⁵ package, where they replaced the decommissioned argcv module. Mailutils has its own configuration package, therefore using Grecs was not expedient. The wordsplit sources had been exported from Grecs and incorporated into Mailutils. Since then Mailutils and Grecs versions or wordsplit were periodically synchronized.

Several other projects, such as GNU Rush⁶ and fileserv⁷, followed suit. It had therefore been decided that it was advisable to have wordsplit as a separate package which could be easily included in another project without incurring unnecessary overhead. This separate package was created on July 7, 2019.

By the end of July 2019, all mentioned packages had switched to using wordsplit as a submodule.

Please send bug reports, questions, suggestions and criticism via email to Sergey Poznyakoff or use the project's bug tracker. When sending bug reports, please make sure to provide the following information:

1. Wordsplit invocation flags.
2. Input string.
3. Produced output.
4. Expected output.

Copyright (C) 2009-2020 Sergey Poznyakoff

Permission is granted to anyone to make or distribute verbatim copies of this document as received, in any medium, provided that the copyright notice and this permission notice are preserved, thus giving the recipient permission to redistribute in turn.

Permission is granted to distribute modified versions of this document, or of portions of it, under the above conditions, provided also that they carry prominent notices stating who last changed them.