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ParsePattern.md

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NAME

ParsePattern -- Create a tokenized string for MatchPattern (V36)

SYNOPSIS

    IsWild = ParsePattern(Source, Dest, DestLength)
    d0                      D1     D2      D3

    LONG ParsePattern(STRPTR, STRPTR, LONG)

FUNCTION

Tokenizes a pattern, for use by MatchPattern. Also indicates if there are any wildcards in the pattern (i.e. whether it might match more than one item). Note that Dest must be at least 2 times as large as Source plus bytes to be (almost) 100% certain of no buffer overflow. This is because each input character can currently expand to 2 tokens (with one exception that can expand to 3, but only once per string). Note: this implementation may change in the future, so you should handle error returns in all cases, but the size above should still be a reasonable upper bound for a buffer allocation.

The patterns are fairly extensive, and approximate some of the ability of Unix/grep "regular expression" patterns. Here are the available tokens:

? Matches a single character.

Matches the following expression 0 or more times.

(ab|cd) Matches any one of the items seperated by '|'. ~ Negates the following expression. It matches all strings that do not match the expression (aka ~(foo) matches all strings that are not exactly "foo"). [abc] Character class: matches any of the characters in the class. [~bc] Character class: matches any of the characters not in the class. a-z Character range (only within character classes). % Matches 0 characters always (useful in "(foo|bar|%)").

  •   Synonym for "#?", not available by default in 2.0.  Available

as an option that can be turned on.

"Expression" in the above table means either a single character (ex: "#?"), or an alternation (ex: "#(ab|cd|ef)"), or a character class (ex: "#[a-zA-Z]").

INPUTS

source - unparsed wildcard string to search for. dest - output string, gets tokenized version of input. DestLength - length available in destination (should be at least as twice as large as source + 2 bytes).

RESULT IsWild - 1 means there were wildcards in the pattern, 0 means there were no wildcards in the pattern, -1 means there was a buffer overflow or other error

BUGS Should set IoErr to something useful (not currently set) on an error.

SEE ALSO

ParsePatternNoCase, MatchPattern, MatchFirst, MatchNext