Nested Quasis

Waldemar Horwat waldemar at google.com
Wed Feb 1 11:28:18 PST 2012


On 01/31/2012 03:04 PM, Allen Wirfs-Brock wrote:
>
> On Jan 31, 2012, at 2:36 PM, Waldemar Horwat wrote:
>
>> On 01/28/2012 02:54 PM, Erik Arvidsson wrote:
>>> Under the open issues for Quasi Literals,
>>> http://wiki.ecmascript.org/doku.php?id=harmony:quasis#nesting , the
>>> topic of nesting is brought up.
>>>
>>> After implementing Quasi Literals in Traceur it is clear that
>>> supporting nested quasi literals is easier than not supporting them.
>>> What is the argument for not supporting nesting? Can we resolve this?
>>
>> This has been hashed out in committee before.  Do you have a solution to the grammar problems, such as having a full ECMAScript parser inside the lexer?  You can't just count parentheses because that breaks regexps.
>
> I would think the solution to this is pretty straightforward.  Basically, a Quasi is not a single token.   the grammar in the proposal can almost be read that way right now.   It should only take a little cleanup to factor it into a pure lexical part and a syntactic part.

I'd love to see this little cleanup.  I thought about it for a while and couldn't come up with it myself; I'm not sure it can even be done.

     Waldemar


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