Add new preprocessor directive syntax¸ using a '!' prefix.

[ikiwiki] / ikiwiki-prefix-directives

#!/usr/bin/perl -i
undef $/; # process whole files at once

my $regex = qr{
        (\\?)           # 1: escape?
        \[\[(!?)        # directive open; 2: optional prefix
        ([-\w]+)        # 3: command
        (               # 4: the parameters (including initial whitespace)
        \s+
                (?:
                        (?:[-\w]+=)?            # named parameter key?
                        (?:
                                """.*?"""       # triple-quoted value
                                |
                                "[^"]+"         # single-quoted value
                                |
                                [^\s\]]+        # unquoted value
                        )
                        \s*                     # whitespace or end
                                                # of directive
                )
        *)              # 0 or more parameters
        \]\]            # directive closed
}sx;

sub handle_directive($$$$) {
        my $escape = shift;
        my $prefix = shift;
        my $directive = shift;
        my $args = shift;

        if (length $escape) {
                return "${escape}[[${prefix}${directive}${args}]]"
        }
        if ($directive =~ m/^(if|more|table|template|toggleable)$/) {
                $args =~ s{$regex}{handle_directive($1, $2, $3, $4)}eg;
        }
        return "[[!${directive}${args}]]"
}

while (<>) {
        s{$regex}{handle_directive($1, $2, $3, $4)}eg;
        print;
}