ABNF to REGEX Library

The ABNF to REGEX library is a pair of PHP functions that validate standard ABNF (RFC 5234) input and generate POSIX and Perl-compatible regular expressions for use in schema and applications.

I provide an online form front-end for these functions at:

http://abnf.msweet.org/

The file "example.php" shows how to implement your own web form.

Functions

abnf_load(string)

This function parses the ABNF contained in the supplied string. On success, it returns an array of rules that can be passed to the "abnf_regex" function.

FALSE is returned on failure, with the following global variables describing the issue:

• "abnf_error" contains a string describing the issue.
• "abnf_errorline" contains the line number in the string where the issue occurred.
• "abnf_errorcol" contains the column number in the string where the issue occurred.

abnf_regex(rules, rulename, mode = ABNF_INSENSITIVE)

This function generates a regular expression for the named rule. If the named rule does not exist, an empty string is returned.

The "mode" parameter can be any of the following constants:

• ABNF_INSENSITIVE : Generates a case-insensitive regular expression.
• ABNF_SENSITIVE : Generates a case-sensitive regular expression.
• ABNF_LOWERCASE : Generates a case-sensitive regular expression with all string literals converted to uppercase.
• ABNF_UPPERCASE : Generates a case-sensitive regular expression with all string literals converted to lowercase.

Legal Stuff

Copyright (c) 2013-2024 Michael R Sweet

This software is provided under the terms of the MIT license, which is provided in the file "LICENSE.md".