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Postings from August 2013
Well, if I'm being offered a fully "pre-parsed" API for 'source'
constant overloadings, all I can say is: yes, please!
Though, I'd suggest that the constant components should be passed in the
same order they appear in the source. That is:
overload::constant source = sub {
my ($keyword, $leftdelim1, $content1, $rightdelim1,
$leftdelim2, $content2, $rightdelim2, $flags) = @_;
...
}
That way, if you need to, you can reconstruct the original source with
just "@_". For example:
overload::constant source = sub {
my ($keyword) = @_;
if ($keyword =~ /qq?/ && $SPECIAL_STRING_MAGIC_REQUESTED) {
return apply_special_string_magic_to(@_);
}
else { # No transformation required so return original source...
return "@_";
}
}
Specifically:
Constant ( $kw, $l1, $c1, $r1, $l2, $c2, $r2,
$fg ) = @_;
'foo' '' '\'' 'foo' '\'' '' '' '' ''
"foo" '' '"' 'foo' '"' '' '' '' ''
q"foo" 'q' '"' 'foo' '"' '' '' '' ''
q/foo/ 'q' '/' 'foo' '/' '' '' '' ''
qq{foo} 'qq' '{' 'foo' '}' '' '' '' ''
qr/foo/xi 'qr' '/' 'foo' '/' '' '' '' 'xi'
m/foo/xi 'm' '/' 'foo' '/' '' '' '' 'xi'
s/foo/bar/gx 's' '/' 'foo' '/' '' 'bar' '/' 'gx'
s{foo}{bar}gx 's' '{' 'foo' '}' '{' 'bar' '}' 'gx'
s(foo)/bar/gx 's' '{' 'foo' '}' '/' 'bar' '/' 'gx'
tr/a-z/A-J/rd 'tr' '/' 'a-z' '/' '' 'A-J' '/' 'rd'
y{a-z}{A-Z} 'y' '{' 'a-z' '}' '{' 'A-Z' '}' ''
123 '' '' '123' '' '' '' '' ''
1.23 '' '' '1.23' '' '' '' '' ''
1.2e3 '' '' '1.2e3' '' '' '' '' ''
077 '0' '' '77' '' '' '' '' ''
0x7A '0x' '' '7A' '' '' '' '' ''
0b101 '0b' '' '101' '' '' '' '' ''
In particular, note that in an s/// or tr/// the second left delimiter
is reported as an empty string, so that "@_" reconstructs the original
source of the constant correctly.
Damian
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