[antlr-interest] [newbie] Quoted identifiers vs. string literals

[Eric]

Hi Chuck,

Off the top of my head I would guess that STRINGLITERAL  is trumping
IDENTIFIER. In other works the lexer generates tokens. The tokens are
created based on the rules in the lexer. Since STRINGLITERAL  comes before
IDENTIFIER, anything that matches STRINGLITERAL will make a
STRINGLITERAL  token even if STRINGLITERAL  defines the same character
string patterns as IDENTIFIER, i.e.  '"' ( ~('\\'|'"') )* '"' trumps '"'
IdentifierStart IdentifierPart* '"'

Can you post your full grammar. I am having to guess at (copied from
Java.g) and believe I have something different.

Also I strongly recommend using ANTLRWorks 1.4.2 for a new user. Note this
is not the latest version of ANTLRWorks which is 1.4.3. I am not
recommending ANTLRWorks 1.4.3 because it can not draw the NFA and DFA
diagrams due to a bug and when I new user tries to do this and it doesn't
work they think they did something wrong when if fact it is a bug from
ANTLR 3.4 which is used by ANTLRWorks 1.4.3.

Also, you can search previous post to the list by using
http://antlr.markmail.org/

Hope that helps, Eric




On Sun, Mar 18, 2012 at 11:22 AM, Charles Daniels <cjdaniels4 at gmail.com>wrote:

> I am very new to ANTLR and I having trouble properly defining part of a
> grammar that I am constructing to recognize a specialized configuration
> file syntax (already defined, so I cannot change it).
>
> The trouble I am having is recognizing the following type of entry in the
> config file:
>
> "name" type "value"
>
>
> where the following rules apply:
>
>   1. The double quotes are a required part of the syntax, both for the
>   name and the value.
>   2. A "name" is essentially a Java identifier
>   3. A "value" is a string literal
>
> I have the following grammar so far:
>
> triplet : IDENTIFIER type STRINGLITERAL ;
>
> type : 'Boolean' | 'Integer' | 'String' ;
>
> STRINGLITERAL : (copied from Java.g)
>
> IDENTIFIER : '"' IdentifierStart IdentifierPart* '"' ;
>
> IdentifierStart : (copied from Java.g)
>
> IdentifierPart : (copied from Java.g)
>
> When I compile this grammar, ANTLR hangs. When I remove the double quotes
> from IDENTIFIER, it compiles successfully. I am guessing that when I
> include the double quotes in IDENTIFIER they are somehow causing the
> compilation to hang due to the double quotes that are also in
> STRINGLITERAL.
>
> Does anybody have any suggestions on how to define this so that I can use
> double quotes around names and values and the compiler doesn't hang?
>
> Thanks,
> Chuck
>
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