[antlr-interest] Empty Quoted String Literal

[G. Richard Bellamy]

Bart & Sam,

Why, I do believe you've hit the nail on the head... and things were 
going so well today!

Thank you both for getting me back on track.

-rb

On 7/27/2011 2:25 PM, Bart Kiers wrote:
> Richard,
>
> Note that I am a C# illiterate, but, isn't the C# literal:
>
>     @""""
>
>
> only just a single quote? If so, then it is no wonder you're getting 
> errors. Parsing:
>
>     WhitespaceInSymbolsLexer lexer = new WhitespaceInSymbolsLexer(new
>     ANTLRStringStream("\""));
>
>
> will also produce the error 'line 1:1 mismatched character '<EOF>' 
> expecting '"'' with me (of course) since a single quote is no valid token.
>
> Regards,
>
> Bart.
>
>
>
> On Wed, Jul 27, 2011 at 11:14 PM, G. Richard Bellamy 
> <rbellamy at pteradigm.com <mailto:rbellamy at pteradigm.com>> wrote:
>
>     Bart,
>
>     When I escape the quotes things work on my end as well - you'll note
>     that I'm passing a set of non-escaped quotes... (C# Verbatim
>     String), so
>     you'll not be able to test this on your end (since Java doesn't
>     have an
>     equivalent to the Verbatim String).
>
>     Thanks again.
>
>     -rb
>
>     On 7/27/2011 2:10 PM, Bart Kiers wrote:
>     > Hi Richard,
>     >
>     > Both ANTLRWorks' debugger, and my Java test rig:
>     >
>     >     import org.antlr.runtime.*;
>     >
>     >     public class Main {
>     >       public static void main(String[] args) throws Exception {
>     >         WhitespaceInSymbolsLexer lexer = new
>     >     WhitespaceInSymbolsLexer(new ANTLRStringStream("\"\""));
>     >         WhitespaceInSymbolsParser parser = new
>     >     WhitespaceInSymbolsParser(new CommonTokenStream(lexer));
>     >         parser.compileUnit();
>     >       }
>     >     }
>     >
>     >
>     > produce no errors when parsing "" (2 double quotes) as input:
>     >
>     >     bart at hades:~/Programming/ANTLR/Demos/WhitespaceInSymbols$
>     java -cp
>     >     antlr-3.3.jar org.antlr.Tool WhitespaceInSymbols.g
>     >     bart at hades:~/Programming/ANTLR/Demos/WhitespaceInSymbols$ javac
>     >     -cp antlr-3.3.jar *.java
>     >     bart at hades:~/Programming/ANTLR/Demos/WhitespaceInSymbols$
>     java -cp
>     >     .:antlr-3.3.jar Main
>     >     bart at hades:~/Programming/ANTLR/Demos/WhitespaceInSymbols$
>     >
>     >
>     > Then there must be something going differently in the CSharp3 target
>     > than in the Java target (note that I am not able to test the CSharp3
>     > target here...).
>     >
>     > Regards,
>     >
>     > Bart.
>     >
>     >
>     > On Wed, Jul 27, 2011 at 11:01 PM, G. Richard Bellamy
>     > <rbellamy at pteradigm.com <mailto:rbellamy at pteradigm.com>
>     <mailto:rbellamy at pteradigm.com <mailto:rbellamy at pteradigm.com>>>
>     wrote:
>     >
>     >     Sam, Bart & Jim, I really appreciate your help on this.
>     >
>     >     Here's a more complete example, without the greedy
>     confusion. I'm
>     >     including the combined grammar and a test rig.
>     >
>     >     I get: CombinedLexer:line 1:2 mismatched character '<EOF>'
>     >     expecting '"'
>     >     just before a NullReferenceException.
>     >
>     >     GRAMMAR:
>     >     ----------------------------
>     >     grammar Combined;
>     >
>     >     options {
>     >     language=CSharp3;
>     >     TokenLabelType=CommonToken;
>     >     output=AST;
>     >     ASTLabelType=CommonTree;
>     >     }
>     >
>     >     @lexer::namespace{StringLiteralLexerTest}
>     >     @parser::namespace{StringLiteralLexerTest}
>     >
>     >     /*
>     >     * Parser Rules
>     >     */
>     >
>     >     public
>     >     compileUnit
>     >     : STRING
>     >     ;
>     >
>     >     /*
>     >     * Lexer Rules
>     >     */
>     >     STRING : '"' ('""' | ~'"')* '"';
>     >
>     >     TEST RIG:
>     >     ------------------------------
>     >     static void Main()
>     >     {
>     >     CombinedLexer lexer = new CombinedLexer(new
>     ANTLRStringStream(@""""));
>     >     //lexer.TraceDestination = new
>     >     ConsoleTextWriter(typeof(CombinedLexer));
>     >
>     >     CommonTokenStream tokenStream = new CommonTokenStream(lexer);
>     >
>     >     CombinedParser parser = new CombinedParser(tokenStream);
>     >     //parser.TraceDestination = new
>     >     ConsoleTextWriter(typeof(CombinedParser));
>     >
>     >     CommonTree parseTree = parser.compileUnit().Tree;
>     >     Console.WriteLine(parseTree.ToStringTree());
>     >     }
>     >
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