[pure-lang-svn] SF.net SVN: pure-lang:[492] pure/trunk/lib/math.pure

[<ag...@us...>]

Revision: 492
          http://pure-lang.svn.sourceforge.net/pure-lang/?rev=492&view=rev
Author:   agraef
Date:     2008-08-14 12:22:54 +0000 (Thu, 14 Aug 2008)

Log Message:
-----------
Overhaul of number predicates.

Modified Paths:
--------------
    pure/trunk/lib/math.pure

Modified: pure/trunk/lib/math.pure
===================================================================
--- pure/trunk/lib/math.pure	2008-08-14 07:59:36 UTC (rev 491)
+++ pure/trunk/lib/math.pure	2008-08-14 12:22:54 UTC (rev 492)
@@ -563,13 +563,33 @@
 /* Additional number predicates. */
 
 complexp x	= case x of x+:y | x<:y = realp x && realp y; _ = 0 end;
-rationalp x	= case x of x%y = bigintp x && bigintp y; _ = 0 end;
-realp x		= intp x || bigintp x || doublep x || rationalp x;
+realp x		= case x of _::int | _::bigint | _::double |
+		            _::bigint%_::bigint = 1; _ = 0 end;
+rationalp x	= case x of _::bigint%_::bigint = 1; _ = 0 end;
 numberp x	= realp x || complexp x;
 
-inexactp x      = doublep x || doublep (re x) || doublep (im x) if numberp x;
-exactp x	= not(doublep x || doublep (re x) || doublep (im x))
-                    if numberp x;
+/* Semantic number predicates. In difference to the syntactic predicates in
+   primitives.pure and above, these check whether the given value can be
+   represented as an object of the given target type (up to rounding
+   errors). Note that if x is of syntactic type X, then it is also of semantic
+   type X. Moreover, intvalp x => bigintvalp x => ratvalp x => realvalp x =>
+   compvalp x <=> numberp x. */
 
-infp x::double	= not nanp x && nanp (x-x);
-nanp x::double	= x===nan;
+compvalp x	= numberp x;
+realvalp x	= compvalp x && im x==0;
+ratvalp x	= realvalp x && (y-y!==nan when y = re x end);
+bigintvalp x	= ratvalp x && den x==1;
+intvalp x	= bigintvalp && int x==x;
+
+/* Check whether a number is exact (i.e., doesn't contain any double
+   components. */
+
+exactp x	= numberp x &&
+		  not (doublep x || doublep (re x) || doublep (im x));
+inexactp x      = numberp x &&
+		  (doublep x || doublep (re x) || doublep (im x));
+
+/* Check for inf and nan values. */
+
+infp x		= case x of x::double = x!==nan && x-x===nan; _ = 0 end;
+nanp x		= case x of x::double = x===nan; _ = 0 end;


This was sent by the SourceForge.net collaborative development platform, the world's largest Open Source development site.