[m-rev.] Re: [m-dev.] '|' as an operator

[David Overton]

On Tue, Feb 11, 2003 at 03:09:47PM +1100, David Overton wrote:
> @@ -870,12 +875,18 @@
>  :- pred parser__get_token(token, token_context,
>  		parser__state(Ops, T), parser__state(Ops, T)).
>  :- mode parser__get_token(out, out, in, out) is semidet.
> -:- mode parser__get_token(in, in, out, in) is det.
>  
> -parser__get_token(Token, Context,
> -		parser__state(FileName, OpTable, VarSet, Tokens0, Names),
> -		parser__state(FileName, OpTable, VarSet, Tokens, Names)) :-
> -	Tokens0 = token_cons(Token, Context, Tokens).
> +parser__get_token(Token, Context, State0, State) :-
> +	State0 ^ tokens = token_cons(Token0, Context, Tokens),
> +	State = ( State0 ^ tokens := Tokens ),
> +	(
> +		State ^ in_list_context = no,
> +		Token0 = ht_sep
> +	->
> +		Token = name("|")
> +	;
> +		Token = Token0
> +	).
>  
>  :- pred parser__unget_token(token, token_context,
>  		parser__state(Ops, T), parser__state(Ops, T)).
> @@ -883,7 +894,9 @@
>  :- mode parser__unget_token(out, out, out, in) is semidet.
>  
>  parser__unget_token(Token, Context, ParseState0, ParseState) :-
> -	parser__get_token(Token, Context, ParseState, ParseState0).
> +	ParseState0 ^ tokens = Tokens,
> +	ParseState = ( ParseState0 ^ tokens := 
> +		token_cons(Token, Context, Tokens) ).
>  
>  :- pred parser__peek_token(token, parser__state(Ops, T), parser__state(Ops, T)).
>  :- mode parser__peek_token(out, in, out) is semidet.
> @@ -896,7 +909,7 @@
>  :- mode parser__peek_token(out, out, in, out) is semidet.
>  
>  parser__peek_token(Token, Context) -->
> -	=(parser__state(_, _, _, Tokens, _)),
> +	Tokens =^ tokens,
>  	{ Tokens = token_cons(Token, Context, _) }.
>  

Forgot about peek_token.  Here is a relative diff:


diff -u parser.m parser.m
--- parser.m	11 Feb 2003 03:53:39 -0000
+++ parser.m	11 Feb 2003 04:23:03 -0000
@@ -876,17 +876,25 @@
 		parser__state(Ops, T), parser__state(Ops, T)).
 :- mode parser__get_token(out, out, in, out) is semidet.
 
-parser__get_token(Token, Context, State0, State) :-
-	State0 ^ tokens = token_cons(Token0, Context, Tokens),
-	State = ( State0 ^ tokens := Tokens ),
-	(
-		State ^ in_list_context = no,
+parser__get_token(Token, Context) -->
+	token_cons(Token0, Context, Tokens) =^ tokens,
+	^tokens := Tokens,
+	check_for_list_context(Token0, Token).
+
+:- pred check_for_list_context(token, token, parser__state(Ops, T),
+		parser__state(Ops, T)).
+:- mode check_for_list_context(in, out, in, out) is det.
+
+check_for_list_context(Token0, Token) -->
+	InListContext =^ in_list_context,
+	{
+		InListContext = no,
 		Token0 = ht_sep
 	->
 		Token = name("|")
 	;
 		Token = Token0
-	).
+	}.
 
 :- pred parser__unget_token(token, token_context,
 		parser__state(Ops, T), parser__state(Ops, T)).
@@ -910,7 +918,8 @@
 
 parser__peek_token(Token, Context) -->
 	Tokens =^ tokens,
-	{ Tokens = token_cons(Token, Context, _) }.
+	{ Tokens = token_cons(Token0, Context, _) },
+	check_for_list_context(Token0, Token).
 
 %-----------------------------------------------------------------------------%
 

-- 
David Overton                  Uni of Melbourne     +61 3 8344 1354
dmo at cs.mu.oz.au                Monash Uni (Clayton) +61 3 9905 5779
http://www.cs.mu.oz.au/~dmo    Mobile Phone         +61 4 0337 4393
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