Update of /cvsroot/monetdb/pathfinder/compiler/semantics
In directory sc8-pr-cvs7.sourceforge.net:/tmp/cvs-serv19085/semantics
Modified Files:
subtyping.c typecheck.brg
Log Message:
-- `none' should be a subtype of every other type. (This partially
reverts a checkin I did some time ago.) `none' is something
like an illegal, non-existing type, so it seems odd that it is
a subtype of every other type. It is, however, consistent with
`none' being the identity with respect to `|' (choice of two types):
( t1 | t2 ) <: t3 ==> t1 <: t3 /\ t2 <: t3
now, since `t1 | none' == `t1':
(t1 | none) <: t1 ==> t1 <: t1 /\ none <: t1
This fixes bug #1579510 (at least, it improves Pathfinder's
behavior; a nice fix would print a more meaningful message).
-- There was a rewrite rule in coreopt.brg which rewrote
main (..., e)
into
empty
if the entire expression had static type empty. This rewrite rule
(a) never did anything until now, since the main() node does not
have a static type, hence, could never be a subtype of empty
and
(b) would have broken the compilation if it did anything.
Rewriting the main() node into an empty() node makes the whole
thing an invalid Core tree!
My typing changes turned (a) into its opposite and I removed the
rewrite to avoid (b).
Index: subtyping.c
===================================================================
RCS file: /cvsroot/monetdb/pathfinder/compiler/semantics/subtyping.c,v
retrieving revision 1.42
retrieving revision 1.43
diff -u -d -r1.42 -r1.43
--- subtyping.c 3 Jan 2007 12:33:01 -0000 1.42
+++ subtyping.c 20 Feb 2007 14:25:48 -0000 1.43
@@ -1156,6 +1156,18 @@
* - 0 indicates not (t1 <: t2)
* - 1 indicates t1 <: t2
* - _ indicates <: must be decided using Antimirov's algorithm.
+ *
+ * NOTE: `none' is a subtype of all other types (but no other type is
+ * a subtype of `none'). This is an outcome of the XOBE algorithm
+ * and seems to be most consistent with choice types:
+ *
+ * ( t1 | t2 ) <: t3 ==> t1 <: t3 /\ t2 <: t3.
+ *
+ * i.e.,
+ *
+ * (t1 | none) <: t1 ==> t1 <: t1 /\ none <: t1.
+ *
+ * (Note that `none' is the identity with respect to `|'.)
*/
#define _ -1
@@ -1175,7 +1187,7 @@
o p m t A m m r g m b i e a o l t d x o t g
n t e e n i i i e a l n a m d e t o e p m m m
e y d ? + * , | & m y c c c r l e g n e e m r c t i m t
t*/
- [ty_none ] ={1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0
}
+ [ty_none ] ={1,1,_,_,_,_,_,_,_,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1
}
,[ty_empty ] ={0,1,_,1,_,1,_,_,_,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0
}
,[ty_named ] ={_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_
}
,[ty_opt ] ={0,_,_,_,_,_,_,_,_,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0
}
@@ -1232,7 +1244,7 @@
o p m t A m m r g m b i e a o l t d x o t g
n t e e n i i i e a l n a m d e t o e p m m m
e y d ? + * , | & m y c c c r l e g n e e m r c t i m t
t*/
- [ty_none ] ={1,0,_,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0
}
+ [ty_none ] ={1,0,_,_,_,_,_,_,_,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0
}
,[ty_empty ] ={0,1,_,_,_,_,_,_,_,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0
}
,[ty_named ] ={_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,0,0
}
,[ty_opt ] ={0,_,_,_,_,_,_,_,_,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0
}
Index: typecheck.brg
===================================================================
RCS file: /cvsroot/monetdb/pathfinder/compiler/semantics/typecheck.brg,v
retrieving revision 1.54
retrieving revision 1.55
diff -u -d -r1.54 -r1.55
--- typecheck.brg 20 Feb 2007 12:06:53 -0000 1.54
+++ typecheck.brg 20 Feb 2007 14:25:48 -0000 1.55
@@ -416,7 +416,18 @@
reduce (kids[1], nts[1]);
reduce (kids[0], nts[0]);
- if (PFty_subtype (TY(R(p)), PFty_star (PFty_item ())))
+ if (PFty_subtype (TY(R(p)), PFty_star (PFty_none ())))
+ /*
+ * Not really okay, but we let it go through with
+ * a warning: the query *statically* evaluated to
+ * the error type (none).
+ *
+ * NOTE: `none' is a subtype of all other types (but
+ * nothing is a subtype of `none'). Hence,
+ * do this check before any other check.
+ */
+ PFinfo (OOPS_WARNING, "query will always return an error");
+ else if (PFty_subtype (TY(R(p)), PFty_star (PFty_item ())))
/* okay, this is a normal query */
;
else if (PFty_subtype (TY(R(p)), PFty_star (PFty_stmt ())))
@@ -425,14 +436,10 @@
else if (PFty_subtype (TY(R(p)), PFty_star (PFty_docmgmt ())))
/* okay, this is a document management query */
;
- else if (PFty_subtype (TY(R(p)), PFty_none ()))
- /* not really okay, but we let it go through with
- * a warning: the query *statically* evaluated to
- * the error type (none). */
- PFinfo (OOPS_WARNING, "query will always return an error");
else
PFoops (OOPS_TYPECHECK,
- "illegal combination of query and update features");
+ "illegal combination of query and update features "
+ "(result type is `%s')", PFty_str (TY(R(p))));
break;
-------------------------------------------------------------------------
Take Surveys. Earn Cash. Influence the Future of IT
Join SourceForge.net's Techsay panel and you'll get the chance to share your
opinions on IT & business topics through brief surveys-and earn cash
http://www.techsay.com/default.php?page=join.php&p=sourceforge&CID=DEVDEV
_______________________________________________
Monetdb-pf-checkins mailing list
[email protected]
https://lists.sourceforge.net/lists/listinfo/monetdb-pf-checkins
