Author: lwall
Date: 2009-11-18 19:05:37 +0100 (Wed, 18 Nov 2009)
New Revision: 29127
Modified:
docs/Perl6/Spec/S02-bits.pod
Log:
[S02] correction from ron.koerner++ on s/multiple/power/
adopt 2's and 5's factoring as normative for both .Str and .perl of Rats
Modified: docs/Perl6/Spec/S02-bits.pod
===================================================================
--- docs/Perl6/Spec/S02-bits.pod 2009-11-18 18:00:56 UTC (rev 29126)
+++ docs/Perl6/Spec/S02-bits.pod 2009-11-18 18:05:37 UTC (rev 29127)
@@ -13,8 +13,8 @@
Created: 10 Aug 2004
- Last Modified: 17 Nov 2009
- Version: 189
+ Last Modified: 18 Nov 2009
+ Version: 190
This document summarizes Apocalypse 2, which covers small-scale
lexical items and typological issues. (These Synopses also contain
@@ -709,12 +709,33 @@
entire way through. The C<.nu> and C<.de> methods will return these
unreduced values. You can use C<$rat.=norm> to normalize the fraction.
The C<.perl> method will produce a decimal number if the denominator is
-a multiple of 10. Otherwise it will normalize and return a rational
-literal of the form -47/3. Stringifying a rational always converts
-to C<Num> and stringifies that, so the rational internal form is
+a power of 10, or normalizable to a power of 10 (that is, having factors
+of only 2 and 5). Otherwise it will normalize and return a rational
+literal of the form C<-47/3>. Stringifying a rational does a similar
+calculation, with the same result on decimal-normalizable fractions,
+but where C<.perl> would produce the C<-47/3> form, stringification instead
+converts to C<Num> and stringifies that, so the rational internal form is
somewhat hidden from the casual user, who would generally prefer
-to see decimal notation.
+to see pure decimal notation.
+ say 1/5; # 0.2 exactly (not via Num)
+ say 1/3; # 0.333333333333333 via Num
+
+ say <2/6>.perl
+ # 1/3
+
+ say 3.14159_26535_89793
+ # 3.141592653589793 including last digit
+
+ say 111111111111111111111111111111111111111111111.123
+ # 111111111111111111111111111111111111111111111.123
+
+ say 555555555555555555555555555555555555555555555/5
+ # 111111111111111111111111111111111111111111111
+
+ say <555555555555555555555555555555555555555555555/5>.perl
+ # 111111111111111111111111111111111111111111111/1
+
=item *
Perl 6 should by default make standard IEEE floating point concepts
