• Jerry Quinn <jlquinn optonline.net> Feb 20 2009
• Ellery Newcomer <ellery-newcomer utulsa.edu> Feb 20 2009

Jerry Quinn <jlquinn optonline.net> writes:

Ellery Newcomer Wrote:

 jerry quinn wrote:
 Ellery Newcomer Wrote:
 Maybe I'm missing something.  The grammar shown in
http://www.digitalmars.com/d/2.0/declaration.html has the following rules:

 BasicType2:
         *
         [ ]
         [ Expression ]
         [ Expression .. Expression ]
         [ Type ]
         delegate Parameters FunctionAttributesopt
         function Parameters FunctionAttributesopt

 Declarator:
         BasicType2 Declarator DeclaratorSuffixesopt
         BasicType2 Identifier DeclaratorSuffixesopt

 With this definition, I don't see how you can get Declarator->Identifier.

 Jerry


 match what it does above multiple times.


 As I'm looking at this further, there seems to be more issues.  In particular,
I don't think the grammar can parse:
 
 int (*x)(char);
 
 as specified.  Doing so gives (my best attempt)
 
 Decl -> BasicType Declarators ;
 BasicType -> int
 Declarators -> DeclaratorInitializer
 DeclaratorInitializer -> Declarator
 Declarator -> BasicType2 Identifier DeclaratorSuffixes
 BasicType2 -> NULL (assuming that the grammar should be revised like this)
 Identifier -> BAD PARSE
 
 


 yeah, if you haven't figured out by now, the grammar is a bunch of hooey.
 
 I spent like a month building an ANTLR grammar based on the above, and 
 then realized much of it was garbage.
 
 Then I spent two months going through the source code and rewriting most 
 of the rules. Just got done with it a week or two ago :) That was all 
 version 1, but it looks the same, so if memory serves the above rules 
 should look something like this:
 
 BasicType2_x:
 	*
 	[ ]
 	[ Expression ]
 	[ Expression .. Expression ]
 	[ Type ]
 	delegate Parameters FunctionAttributesopt
 	function Paramters FunctionAttributesopt
 BasicType2:
 	BasicType2_x
 	BasicType2 BasicType2_x
 	epsilon
 Declarator:
 	BasicType2 Identifier DeclaratorSuffixesopt
 	BasicType2 ( Declarator ) DeclaratorSuffixesopt
 
 Apologies for any BNF misuse


Cool.  Do you feel like posting the whole thing somewhere?  

As an aside comment, it might be better from a grammar perspective to make
usage of BasicType2 optional, rather than have the epsilon in the BasicType2
rule itself.  Then every rule would consume at least 1 token, and _opt is the
only expansion shortcut needed.

In the form show, you can simplify the BasicType2 rule to

BasicType2:
  BasicType2 BasicType2_x
  epsilon

Ellery Newcomer <ellery-newcomer utulsa.edu> writes:

Jerry Quinn wrote:
 Ellery Newcomer Wrote:
 
 jerry quinn wrote:
 Ellery Newcomer Wrote:
 Maybe I'm missing something.  The grammar shown in
http://www.digitalmars.com/d/2.0/declaration.html has the following rules:

 BasicType2:
         *
         [ ]
         [ Expression ]
         [ Expression .. Expression ]
         [ Type ]
         delegate Parameters FunctionAttributesopt
         function Parameters FunctionAttributesopt

 Declarator:
         BasicType2 Declarator DeclaratorSuffixesopt
         BasicType2 Identifier DeclaratorSuffixesopt

 With this definition, I don't see how you can get Declarator->Identifier.

 Jerry


 match what it does above multiple times.



 int (*x)(char);

 as specified.  Doing so gives (my best attempt)

 Decl -> BasicType Declarators ;
 BasicType -> int
 Declarators -> DeclaratorInitializer
 DeclaratorInitializer -> Declarator
 Declarator -> BasicType2 Identifier DeclaratorSuffixes
 BasicType2 -> NULL (assuming that the grammar should be revised like this)
 Identifier -> BAD PARSE



 I spent like a month building an ANTLR grammar based on the above, and 
 then realized much of it was garbage.

 Then I spent two months going through the source code and rewriting most 
 of the rules. Just got done with it a week or two ago :) That was all 
 version 1, but it looks the same, so if memory serves the above rules 
 should look something like this:

 BasicType2_x:
 	*
 	[ ]
 	[ Expression ]
 	[ Expression .. Expression ]
 	[ Type ]
 	delegate Parameters FunctionAttributesopt
 	function Paramters FunctionAttributesopt
 BasicType2:
 	BasicType2_x
 	BasicType2 BasicType2_x
 	epsilon
 Declarator:
 	BasicType2 Identifier DeclaratorSuffixesopt
 	BasicType2 ( Declarator ) DeclaratorSuffixesopt

 Apologies for any BNF misuse


 Cool.  Do you feel like posting the whole thing somewhere?  


knock yourself out http://www.personal.utulsa.edu/~ellery-newcomer/antlrd.g

D version 1, ANTLR version 2, note it isn't really complete yet; I 
haven't gotten around to AST construction.

Oh, and don't look at the lexer part. It's ugly as sin.
 
 As an aside comment, it might be better from a grammar perspective to make
usage of BasicType2 optional, rather than have the epsilon in the BasicType2
rule itself.  Then every rule would consume at least 1 token, and _opt is the
only expansion shortcut needed.
 
 In the form show, you can simplify the BasicType2 rule to
 
 BasicType2:
   BasicType2 BasicType2_x
   epsilon
 


doh. I knew that.