[m-dev.] Re: zero-arity higher-order function terms and apply/1

[Fergus Henderson]

Tyson Richard DOWD, you wrote:

> > compiler/mercury_to_mercury.m:
> > 	Fix the output of nullary higher-order function insts:
> > 	previously it would output `(func() = Mode is Det)',
> > 	but the correct output is `((func) = Mode is Det)'.
> 
> You should also modify std_util:type_name to use the
> 	(func) = Type 
> syntax.

Ah, good point.

--

More changes to support nullary higher-order function terms.

library/std_util.m:
	Change type_name/1 so that it outputs nullary higher-order
	function types correctly.

tests/hard_coded/nullary_ho_func.m:
tests/hard_coded/nullary_ho_func.exp:
	Add test case for type_name/1 on nullary h.o. function type.

Index: std_util.m
===================================================================
RCS file: /home/staff/zs/imp/mercury/library/std_util.m,v
retrieving revision 1.95
diff -u -r1.95 std_util.m
--- std_util.m	1997/07/18 04:42:00	1.95
+++ std_util.m	1997/07/24 07:15:25
@@ -1202,9 +1202,19 @@
 		TypeName = Name
 	;
 		( Name = "func" -> IsFunc = yes ; IsFunc = no ),
-		type_arg_names(ArgTypes, IsFunc, ArgTypeNames),
-		string__append_list([Name, "(" | ArgTypeNames], 
-			TypeName)
+		(
+			IsFunc = yes,
+			ArgTypes = [FuncRetType]
+		->
+			FuncRetTypeName = type_name(FuncRetType),
+			string__append_list(
+				["((func) = ", FuncRetTypeName, ")"],
+				TypeName)
+		;
+			type_arg_names(ArgTypes, IsFunc, ArgTypeNames),
+			string__append_list([Name, "(" | ArgTypeNames], 
+				TypeName)
+		)
 	).
 
 :- pred type_arg_names(list(type_info), bool, list(string)).


cvs diff: Diffing .
Index: nullary_ho_func.exp
===================================================================
RCS file: /home/staff/zs/imp/tests/hard_coded/nullary_ho_func.exp,v
retrieving revision 1.1
diff -u -r1.1 nullary_ho_func.exp
--- nullary_ho_func.exp	1997/07/23 15:29:14	1.1
+++ nullary_ho_func.exp	1997/07/24 07:36:45
@@ -4,3 +4,5 @@
 apply_nullary_func(F) = 42
 Y = apply(G) failed
 Z = 42
+type_of(Z) = ((func) = int)
+type_name(type_of(Z)) = ((func) = int)
Index: nullary_ho_func.m
===================================================================
RCS file: /home/staff/zs/imp/tests/hard_coded/nullary_ho_func.m,v
retrieving revision 1.1
diff -u -r1.1 nullary_ho_func.m
--- nullary_ho_func.m	1997/07/23 15:29:16	1.1
+++ nullary_ho_func.m	1997/07/24 07:38:07
@@ -43,5 +43,7 @@
 		print("Z = "), print(Z), nl
 	;
 		print("Y = apply(G) failed"), nl
-	).
+	),
+	print("type_of(F) = "), print(type_of(F)), nl,
+	print("type_name(type_of(F)) = "), print(type_name(type_of(F))), nl.
 

-- 
Fergus Henderson <fjh at cs.mu.oz.au>   |  "I have always known that the pursuit
WWW: <http://www.cs.mu.oz.au/~fjh>   |  of excellence is a lethal habit"
PGP: finger fjh at 128.250.37.3         |     -- the last words of T. S. Garp.