Re: [Help-source-highlight] regexp in javascript.lang (3rd try!)

[Lorenzo Bettini]

address@hidden wrote:
> Last time I suggested an ugly regexp definition for
> javascript.lang to avoid matching /* */ comments:
>
> http://lists.gnu.org/archive/html/help-source-highlight/2008-09/msg00000.html 
>
>
> On second thought (or third thought) I don't like this because it
> matches cases where there are two division operators in a single
> expression, such as:
>
> document.write('<table><tr><td>25% = '+(25/100)+'</td></tr></table>');
>
> Here is a proposed javascript.lang to fix these problems.  It does the
> following:
> * first check if the input matches a comment
> * next check if it matches a division operator, which can occur only
> after a number, an identifier, or certain symbols
> * finally check if it matches a regular expression
>
> Note that it is no longer based on the java.lang because the order of
> the definitions is important.  (Hence, this would not work with 
> source-highlight 2.10, where the matching algorithm was different, but 
> does work with source-highlight 2.11.)
>
> The disadvantages:
> * it no longer reuses java.lang
> * the division operator definitions are ugly
> The advantages:
> * it works in all possible cases (I hope)
> * it simplifies the regexp definition
>
> What do you think?
>
> include "c_comment.lang"
>
> keyword =
> "abstract|break|case|catch|class|const|continue|debugger|default|delete|do|else|enum|export|extends|false|final|finally|for|function|goto|if|implements|in|instanceof|interface|native|new|null|private|protected|prototype|public|return|static|super|switch|synchronized|throw|throws|this|transient|true|try|typeof|var|volatile|while|with" 
>
>
> (symbol,normal,symbol) = `(\+\+|--|\)|\])(\s*)(/=?(?![*/]))`
> (number,normal,symbol) =
> `(0x[[:xdigit:]]+|(?:[[:digit:]]*\.)?[[:digit:]]+(?:[eE][+-]?[[:digit:]]+)?)(\s*)(/(?![*/]))` 
>
> (normal,symbol) = `([[:alpha:]$_][[:alnum:]$_]*\s*)(/=?(?![*/]))`
>
> regexp = '/(\\.|[^*\\/])(\\.|[^\\/])*/[gim]*'
>
> include "number.lang"
>
> include "c_string.lang"
>
> include "symbols.lang"
>
> cbracket = "{|}"
>
> include "function.lang"

Actually it works also this way, and it reuses most of java.lang (see 
the attached file);

what do you think?

cheers
        Lorenzo

--
Lorenzo Bettini, PhD in Computer Science, DI, Univ. Torino
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# Javascript lang definition file

# first check if the input matches a comment
include "c_comment.lang"

# next check if it matches a division operator, which can occur only
# after a number, an identifier, or certain symbols
(symbol,normal,symbol) = 
        `(\+\+|--|\)|\])(\s*)(/=?(?![*/]))`
(number,normal,symbol) =
        
`(0x[[:xdigit:]]+|(?:[[:digit:]]*\.)?[[:digit:]]+(?:[eE][+-]?[[:digit:]]+)?)(\s*)(/(?![*/]))`
(normal,symbol) = 
        `([[:alpha:]$_][[:alnum:]$_]*\s*)(/=?(?![*/]))`

# finally check if it matches a regular expression 
regexp = '/(\\.|[^*\\/])(\\.|[^\\/])*/[gim]*' 

include "java.lang"

subst keyword = 
"abstract|break|case|catch|class|const|continue|debugger|default|delete|do|else|enum|export|extends|false|final|finally|for|function|goto|if|implements|in|instanceof|interface|native|new|null|private|protected|prototype|public|return|static|super|switch|synchronized|throw|throws|this|transient|true|try|typeof|var|volatile|while|with"