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Re: ruby-mode interpolated quotes error
From: |
Bob Proulx |
Subject: |
Re: ruby-mode interpolated quotes error |
Date: |
Fri, 2 May 2014 17:55:33 -0600 |
User-agent: |
Mutt/1.5.23 (2014-03-12) |
Bob Proulx wrote:
> Andrew Pennebaker wrote:
> > Specifically, the initial double quote on line 46 should be colored yellow,
> > like the end double quote, and the single quoted string above.
> >
> > Anyone else experience this?
>
> The #{...} construct causes the character immediately preceding the
> '#' to be colored in the variable face color.
This motivated me to poke into the problem a little. The problem
appears to be ruby-match-expression-expansion which is looking for any
character not a backslash before the #{...}.
(defun ruby-match-expression-expansion (limit)
(when (re-search-forward
"[^\\]\\(\\\\\\\\\\)*\\(#\\({[^}\n\\\\]*\\(\\\\.[^}\n\\\\]*\\)*}\\|\\(\\$\\|@\\|@@\\)\\(\\w\\|_\\)+\\)\\)"
limit 'move)
(or (ruby-in-ppss-context-p 'string)
(ruby-match-expression-expansion limit))))
It is trying to avoid matching a sub-expression in this case. Two
test cases would be:
"abc#{def}ghi"
"abc\#{def}ghi"
In the first #{def} is a subexpression. In the second the # is
escaped and is not evaluated.
So what is needed is a way to match a # that is not preceded by a
backslash but not to include the non-backslash character in the
expression. Or another method to accomplish the task. I am only an
infrequent elisp hacker and am unfamiliar with the idioms needed to
avoid this problem.
Anyone else on the list know a good idiom to use? It needs to match
but ignore the leading context. (This is the opposite of the "trailing
context" match feature provided by lex.)
As a quick hack to alleviate your particular symptom, while creating a
more rare different one, you could remove the [^\\] part from the
front of the expression. That would no longer match the non-backslash
in front of the #{...} construct and your case would work correctly.
It then would miscolor the new case "abc\#{def}ghi" which is not a
sub-expression due to the escape but would still be colored as if it
were. That might be a less annoying problem.
Bob
--- ruby-mode.el.orig 2014-05-02 17:29:15.312413975 -0600
+++ ruby-mode.el 2014-05-02 17:27:31.935234984 -0600
@@ -1578,7 +1578,7 @@
"Additional expressions to highlight in Ruby mode.")
(defun ruby-match-expression-expansion (limit)
- (when (re-search-forward
"[^\\]\\(\\\\\\\\\\)*\\(#\\({[^}\n\\\\]*\\(\\\\.[^}\n\\\\]*\\)*}\\|\\(\\$\\|@\\|@@\\)\\(\\w\\|_\\)+\\)\\)"
limit 'move)
+ (when (re-search-forward
"\\(\\\\\\\\\\)*\\(#\\({[^}\n\\\\]*\\(\\\\.[^}\n\\\\]*\\)*}\\|\\(\\$\\|@\\|@@\\)\\(\\w\\|_\\)+\\)\\)"
limit 'move)
(or (ruby-in-ppss-context-p 'string)
(ruby-match-expression-expansion limit))))