ParsePattern

Create a tokenized string for MatchPattern()

Declaration

Source position: amigados.pas line 1689

Function result

1

There are wildcards in the pattern (it might match more than one string).

0

No wildcards in it, all went fine.

-1

An error happened. IoErr() gives additional information in that case.

Description

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]").

See also