[m-rev.] for review: fix dummy type bug in construct.construct

[Ian MacLarty]

For review by Zoltan.

Estimated hours taken: 1
Branches: main

Fix a bug reported by Peter Ross, where dummy type terms could not be
constructed using construct.construct.

library/construct.m:
	Change get_functor_ordinal to return 0 for the ordinal number if
	the type is a dummy type.

	Handle the case where the type_ctor_rep is MR_TYPECTOR_REP_DUMMY 
	in construct.construct by just setting the value of the new term to 0
	(the value of the term should never be looked at).

tests/hard_coded/Mmakefile:
tests/hard_coded/dummy_type_construct.exp:
tests/hard_coded/dummy_type_construct.m:
	Add a regression test.  Previously this test failed with 
	"Mercury runtime: bad type_ctor_rep in construct:construct".

Index: library/construct.m
===================================================================
RCS file: /home/mercury1/repository/mercury/library/construct.m,v
retrieving revision 1.22
diff -u -r1.22 construct.m
--- library/construct.m	19 Sep 2005 04:28:59 -0000	1.22
+++ library/construct.m	19 Nov 2005 02:08:53 -0000
@@ -339,6 +339,7 @@
         case MR_TYPECTOR_REP_NOTAG_GROUND:
         case MR_TYPECTOR_REP_NOTAG_GROUND_USEREQ:
         case MR_TYPECTOR_REP_TUPLE:
+        case MR_TYPECTOR_REP_DUMMY:
             Ordinal = 0;
             break;
 
@@ -590,6 +591,16 @@
             }
             break;
 
+        case MR_TYPECTOR_REP_DUMMY:
+            {
+                /*
+                ** The value of the dummy type will never be looked at,
+                ** so just set it to zero.
+                */
+                new_data = (MR_Word) 0;
+                break;
+            }
+
         default:
             new_data = (MR_Word) 0;     /* avoid a warning */
             MR_fatal_error(""bad type_ctor_rep in construct:construct"");
Index: tests/hard_coded/Mmakefile
===================================================================
RCS file: /home/mercury1/repository/tests/hard_coded/Mmakefile,v
retrieving revision 1.274
diff -u -r1.274 Mmakefile
--- tests/hard_coded/Mmakefile	3 Nov 2005 07:03:16 -0000	1.274
+++ tests/hard_coded/Mmakefile	19 Nov 2005 02:37:46 -0000
@@ -47,6 +47,7 @@
 	dos \
 	dot_separator \
 	dst_test \
+	dummy_type_construct \
 	dupcall_impurity \
 	dupcall_types_bug \
 	elim_special_pred \
Index: tests/hard_coded/dummy_type_construct.exp
===================================================================
RCS file: tests/hard_coded/dummy_type_construct.exp
diff -N tests/hard_coded/dummy_type_construct.exp
--- /dev/null	1 Jan 1970 00:00:00 -0000
+++ tests/hard_coded/dummy_type_construct.exp	19 Nov 2005 02:54:38 -0000
@@ -0,0 +1,5 @@
+univ_cons(dummy)
+Unable to construct type.
+0
+get_functor_ordinal failed.
+Functor = dummy, Arity = 0, Args = []
Index: tests/hard_coded/dummy_type_construct.m
===================================================================
RCS file: tests/hard_coded/dummy_type_construct.m
diff -N tests/hard_coded/dummy_type_construct.m
--- /dev/null	1 Jan 1970 00:00:00 -0000
+++ tests/hard_coded/dummy_type_construct.m	19 Nov 2005 02:54:15 -0000
@@ -0,0 +1,38 @@
+:- module dummy_type_construct.
+:- interface.
+:- import_module io.
+:- pred main(io::di, io::uo) is det.
+:- implementation.
+
+:- import_module construct, type_desc, list, string, deconstruct.
+
+:- type dummy ---> dummy.
+
+main(!IO) :-
+	( DummyVal1 = construct.construct(type_of(_:dummy), 0, []) ->
+		io.write(DummyVal1, !IO)
+	;
+		io.write_string("Unable to construct type.", !IO)
+	),
+	io.nl(!IO),
+	( DummyVal2 = construct.construct(type_of(_:dummy), 1, []) ->
+		io.write(DummyVal2, !IO)
+	;
+		io.write_string("Unable to construct type.", !IO)
+	),
+	io.nl(!IO),
+	( get_functor_ordinal(type_of(_:dummy), 0, Ordinal1) ->
+		io.write_int(Ordinal1, !IO)
+	;
+		io.write_string("get_functor_ordinal failed.", !IO)
+	),
+	io.nl(!IO),
+	( get_functor_ordinal(type_of(_:dummy), 1, Ordinal2) ->
+		io.write_int(Ordinal2, !IO)
+	;
+		io.write_string("get_functor_ordinal failed.", !IO)
+	),
+	io.nl(!IO),
+	deconstruct.deconstruct(dummy, canonicalize, Functor, Arity, Args),
+	io.format("Functor = %s, Arity = %i, Args = %s\n", [
+		s(Functor), i(Arity), s(string.string(Args))], !IO).
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