r29128 - docs/Perl6/Spec

[pugs-c...@feather.perl6.nl]

Author: lwall
Date: 2009-11-18 19:51:35 +0100 (Wed, 18 Nov 2009)
New Revision: 29128

Modified:
docs/Perl6/Spec/S02-bits.pod
Log:
[S02] more Rat-to-Str fine-tuning wrt negative denominators

Modified: docs/Perl6/Spec/S02-bits.pod
===================================================================
--- docs/Perl6/Spec/S02-bits.pod 2009-11-18 18:05:37 UTC (rev 29127)
+++ docs/Perl6/Spec/S02-bits.pod 2009-11-18 18:51:35 UTC (rev 29128)
@@ -708,9 +708,10 @@
represent, say, dollars and cents, the denominator may stay 100 the
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.
+(This also forces the sign on the denominator to be positive.)
The C<.perl> method will produce a decimal number if the denominator 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
+of only 2 and 5 (and -1)). 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
@@ -2864,7 +2865,12 @@
The purpose of this would be to facilitate compile-time analysis of
multi-method dispatch, when the user prefers angle notation as the
most readable way to represent a list of numbers, which it often is.
+It also gives us a reasonable way of visually isolating any known
+literal format as a single syntactic unit:

+ <-1+2i>.polar
+ (-1+2i).polar # same, but less clearly a literal
+
The degenerate case C<< <> >> is disallowed as a probable attempt to
do IO in the style of Perl 5; that is now written C<lines()>. (C<<
<STDIN> >> is also disallowed.) Empty lists are better written with