(30/211) 3063 - 4.3pre13: Perl highlighting: autoquoting hash subscripts

Background:

In Perl, if a hash called %h has an element whose key is 'foo', you can address it in two equivalent ways:

$h{'foo'}
$h{foo}

In the second case, 'foo' is said to be autoquoted.


The bug:

Create and save this file:


#\!/usr/bin/perl -l

my %hash = (height => 2, width => 3);
my $rh = \%hash;

print $hash{height};
print $$rh{height};
print $rh->{height};

my @a = map {quotemeta} keys %hash;
for (@a) {print};


In each of the three print statements, jEdit correctly spots that \`height' is autoquoted, and highlights it as a literal string. However, in the last two lines, it also highlights \`quotemeta' and \`print' as literal strings; this is a bug.

A heuristic that's probably good enough is to autoquote the contents of the braces only if the open-brace is immediately preceded by a non-blank character. That would fix the behaviour in this example.

We probably need a fix for bug 1946895 (look-behind not working) before we can fix this autoquoting bug. If we had that, a possible fix would be to change this paragraph of perl.xml --


<\!-- non-quoted literals in hashes -->
<SPAN_REGEXP TYPE="OPERATOR" HASH_CHAR="{" NO_LINE_BREAK="TRUE" DELEGATE="LITERAL">
<BEGIN>\\{(?=\s\*\[\p{Alpha}_\-\]\[\p{Alnum}_\]\*\s\*\\})</BEGIN>
<END>}</END>
</SPAN_REGEXP>


-- to look like this:


<\!-- non-quoted literals in hashes -->
<SPAN_REGEXP TYPE="OPERATOR" HASH_CHAR="{" NO_LINE_BREAK="TRUE" DELEGATE="LITERAL">
<BEGIN>(?&lt;=\S)\\{(?=\s\*\[\p{Alpha}_\-\]\[\p{Alnum}_\]\*\s\*\\})</BEGIN>
<END>}</END>
</SPAN_REGEXP>


(The change consists of a few characters added immediately after <BEGIN> tag.)

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