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IDProjectCategoryView StatusDate SubmittedLast Update
0000231mercuryBugpublic2011-11-22 16:302014-10-09 12:48
Reportercolanderman 
Assigned To 
PrioritynormalSeveritytrivialReproducibilityalways
StatusnewResolutionopen 
Product Version 
Target VersionFixed in Version 
Summary0000231: No way to specify instantiatedness of char type
DescriptionThere is currently no way to specify the instantiatedness of a char type, e.g.:

:- inst whitespace ---> ' '; '\t'; '\n'.

The above instantiatednesses are represented as atoms, but since instantiatednesses of character values are internally represented as type char_const(), this leads to mode errors such as:

Final instantiatedness of `HeadVar__1' was `bound('\t' ; '\n' ; ' ')',
expected final instantiatedness was `bound('\t' ; '\n' ; ' ')'.

Attached is a patch which fixes this bug.
TagsNo tags attached.
Attached Files
  • ? file icon char_inst.m (222 bytes) 2011-11-22 16:30
  • patch file icon mercury-compiler-char-inst.patch (1,974 bytes) 2011-11-22 16:31 - 
    Index: compiler/inst_match.m
===================================================================
RCS file: /home/mercury/mercury1/repository/mercury/compiler/inst_match.m,v
retrieving revision 1.94
diff -u -u -r1.94 inst_match.m
--- compiler/inst_match.m	23 May 2011 05:08:04 -0000	1.94
+++ compiler/inst_match.m	22 Nov 2011 05:30:28 -0000
@@ -783,6 +783,30 @@
             ArityA > ArityB
         )
     ;
+        ConsIdA = char_const(CharA),
+        ConsIdB = cons(QNameB, _, _)
+    ->
+        string.char_to_string(CharA, NameA),
+        ( QNameB = unqualified(NameB)
+        ; QNameB = qualified(_, NameB)
+        ),
+        compare((>), NameA, NameB)
+    ;
+        ConsIdA = cons(QNameA, ArityA, _),
+        ConsIdB = char_const(CharB)
+    ->
+        ( QNameA = unqualified(NameA)
+        ; QNameA = qualified(_, NameA)
+        ),
+        string.char_to_string(CharB, NameB),
+        compare(O, NameA, NameB),
+        (
+            O = (>)
+        ;
+            O = (=),
+            ArityA > 0
+        )
+    ;
         compare((>), ConsIdA, ConsIdB)
     ).
 
Index: compiler/prog_data.m
===================================================================
RCS file: /home/mercury/mercury1/repository/mercury/compiler/prog_data.m,v
retrieving revision 1.235
diff -u -u -r1.235 prog_data.m
--- compiler/prog_data.m	6 Sep 2011 05:20:43 -0000	1.235
+++ compiler/prog_data.m	22 Nov 2011 05:30:28 -0000
@@ -1617,6 +1617,20 @@
         ArityA = ArityB,
         SymNameB = unqualified("{}")
     ;
+        ConsIdA = char_const(CharA),
+        ConsIdB = cons(SymNameB, ArityB, _)
+    ->
+        ArityB = 0,
+        SymNameB = unqualified(StringB),
+        string.char_to_string(CharA, StringB)
+    ;
+        ConsIdA = cons(SymNameA, ArityA, _),
+        ConsIdB = char_const(CharB)
+    ->
+        ArityA = 0,
+        SymNameA = unqualified(StringA),
+        string.char_to_string(CharB, StringA)
+    ;
         ConsIdA = ConsIdB
     ).
    patch file icon mercury-compiler-char-inst.patch (1,974 bytes) 2011-11-22 16:31 +

-Relationships
+Relationships

-Notes

~0000795

wangp (developer)

2014-10-09 12:48

 Applying the patch as-is would be unsafe. If you try to switch on the variable following the call to is_whitespace, e.g.

is_whitespace(C),
( C = (' '), ...
; C = ('\t'), ...
; C = ('\n'), ...
)

The inst of C is represented as a list of cons/3 functors and the cases as `char_const' functors. Switch detection does not see them as equivalent so replaces the disjunction by `fail'. I assume other parts of the compiler may have similar problems.
+Notes

-Issue History
Date Modified Username Field Change
2011-11-22 16:30 colanderman New Issue
2011-11-22 16:30 colanderman File Added: char_inst.m
2011-11-22 16:31 colanderman File Added: mercury-compiler-char-inst.patch
2014-10-09 12:48 wangp Note Added: 0000795
+Issue History