Module Agrep

The type of compiled search patterns

Compile a search pattern. The syntax for patterns is similar to that of the Unix shell. The following constructs are recognized:

• ? match any single character
• * match any sequence of characters
• [..] character set: ranges are denoted with -, as in [a-z]; an initial ^, as in [^0-9], complements the set
• & conjunction (e.g. sweet&sour)
• | alternative (e.g. high|low)
• (..) grouping
• \ escape special characters; the special characters are \?*[]&|().

The optional argument transl is a character translation table. This is a string s of length 256 that ``translates'' a character c to the character s.(Char.code c). A character of the text matches a character of the pattern if they both translate to the same character according to transl. If transl is not provided, the identity translation (two characters match iff they are equal) is assumed. Useful predefined translation tables are provided in Agrep.Iso8859_15.

Exception thrown by Agrep.pattern when the given pattern is syntactically incorrect. The integer argument is the character number where the syntax error occurs.

Agrep.pattern_string s returns a pattern that matches exactly the string s and nothing else. The optional parameter transl is as in Agrep.pattern.

string_match pat text tests whether the string text matches the compiled pattern pat. The optional parameter numerrs is the number of errors permitted. One error corresponds to a substitution, an insertion or a deletion of a character. numerrs default to 0 (exact match). The optional parameter wholeword is true if the pattern must match a whole word, false if it can match inside a word. wholeword defaults to false (match inside words).

Same as Agrep.string_match, but restrict the match to the substring of the given string starting at character number pos and extending len characters.

Same as Agrep.substring_match, but return the smallest number of errors such that the substring matches the pattern. That is, it returns 0 if the substring matches exactly, 1 if the substring matches with one error, etc. Return max_int if the substring does not match the pattern with at most numerrs errors.