groovy

enum definition does not allow trailing comma

Details

  • Type: Bug Bug
  • Status: Closed Closed
  • Priority: Major Major
  • Resolution: Fixed
  • Affects Version/s: 1.5.6
  • Fix Version/s: 1.7.3, 1.8-beta-1
  • Component/s: parser
  • Labels:
    None
  • Environment:
    Any
  • Number of attachments :
    1

Description

The Groovy parser does not allow a trailing comma in an enum definition:

enum Foo {
X, Y, Z,
}

According to the Java language specification (V. 3):

EnumDeclaration: ClassModifiersopt enum Identifier Interfacesopt EnumBody
EnumBody: { EnumConstantsopt ,opt EnumBodyDeclarationsopt }

Note the ",opt" in the EnumBody.

  1. File
    Foo.groovy
    19/Sep/08 11:10 AM
    0.0 kB
    G. Ralph Kuntz, MD

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Paul King added a comment -

Actually, it does allow:

enum Foo { X, Y, Z, }

but not this:

enum Foo { X, Y, Z,
}
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Paul King added a comment - Actually, it does allow: enum Foo { X, Y, Z, } but not this: enum Foo { X, Y, Z, }
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Paul King added a comment - - edited

With this horrible hack to groovy.g:

@@ -1101,8 +1101,10 @@
 enumConstants
     :
         enumConstant
-        ( options{greedy=true;}: COMMA! nls! enumConstant )*
-        ( COMMA! nls! )?            // trailing extra comma is OK
+        // guard shouldn't be needed here - perhaps an antlr bug?
+        // dummy space to keep antlr quiet about superfluous guard
+        ( options{greedy=true;}:
+            (COMMA nls IDENT) => COMMA! nls! enumConstant | " ")*
+        ( COMMA! )?            // trailing extra comma is OK
     ;

both variations are now parsed correctly.
I think there is an antlr bug lurking in there somewhere.
At least I couldn't think of a way to do what we want.

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Paul King added a comment - - edited With this horrible hack to groovy.g : @@ -1101,8 +1101,10 @@ enumConstants : enumConstant - ( options{greedy=true;}: COMMA! nls! enumConstant )* - ( COMMA! nls! )? // trailing extra comma is OK + // guard shouldn't be needed here - perhaps an antlr bug? + // dummy space to keep antlr quiet about superfluous guard + ( options{greedy=true;}: + (COMMA nls IDENT) => COMMA! nls! enumConstant | " ")* + ( COMMA! )? // trailing extra comma is OK ; both variations are now parsed correctly. I think there is an antlr bug lurking in there somewhere. At least I couldn't think of a way to do what we want.
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blackdrag blackdrag added a comment -

I guess it is that greedy option causing the problem... hmm... please don't commit that yet

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blackdrag blackdrag added a comment - I guess it is that greedy option causing the problem... hmm... please don't commit that yet
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Paul King added a comment -

This one seems to be cleaner:

-        ( options{greedy=true;}: COMMA! nls! enumConstant )*
-        ( COMMA! nls! )?            // trailing extra comma is OK
+        ( options{greedy=true;}: (COMMA nls annotationsOpt IDENT) => COMMA! nls! enumConstant )*
+        ( COMMA! )?            // trailing extra comma is OK
Show
Paul King added a comment - This one seems to be cleaner: - ( options{greedy= true ;}: COMMA! nls! enumConstant )* - ( COMMA! nls! )? // trailing extra comma is OK + ( options{greedy= true ;}: (COMMA nls annotationsOpt IDENT) => COMMA! nls! enumConstant )* + ( COMMA! )? // trailing extra comma is OK
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Paul King added a comment -

Previous attempt still had an Antlr warning.
Below was best I could do without a warning.
Incorporates amendment to GROOVY-3986:

/** Guard for enumConstants.  */
enumConstantsStart
    :   annotationsOpt IDENT (LCURLY | LPAREN | nls (SEMI | COMMA | modifiersOpt | RCURLY))
    ;

/** Comma-separated list of one or more enum constant definitions.  */
enumConstants
    :
        enumConstant
        (    options {generateAmbigWarnings=false;} :
            (nls (RCURLY | classField)) => { break; /* leave ()* loop */ }
        |   nls! COMMA!
            (
                (nls (RCURLY | classField)) => { break; /* leave ()* loop */ }
            |
                (nls annotationsOpt IDENT) => nls! enumConstant
            )
        )*
    ;
Show
Paul King added a comment - Previous attempt still had an Antlr warning. Below was best I could do without a warning. Incorporates amendment to GROOVY-3986 : /** Guard for enumConstants. */ enumConstantsStart : annotationsOpt IDENT (LCURLY | LPAREN | nls (SEMI | COMMA | modifiersOpt | RCURLY)) ; /** Comma-separated list of one or more enum constant definitions. */ enumConstants : enumConstant ( options {generateAmbigWarnings= false ;} : (nls (RCURLY | classField)) => { break ; /* leave ()* loop */ } | nls! COMMA! ( (nls (RCURLY | classField)) => { break ; /* leave ()* loop */ } | (nls annotationsOpt IDENT) => nls! enumConstant ) )* ;
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Paul King added a comment -

Patch as per last comment applied. Thanks for reporting the issue.

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Paul King added a comment - Patch as per last comment applied. Thanks for reporting the issue.

People

  • Assignee:
    Paul King
    Reporter:
    G. Ralph Kuntz, MD
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  • Created:
    Updated:
    Resolved: