[svn:perl6-synopsis] r14531 - doc/trunk/design/syn

Author: larry
Date: Mon Mar 31 11:15:33 2008
New Revision: 14531

Modified:
doc/trunk/design/syn/S03.pod

Log:
Some clarifications on Num and Int coercions.
Removed lame joke about truncating rats.


Modified: doc/trunk/design/syn/S03.pod
 ========================================
====================================
==
--- doc/trunk/design/syn/S03.pod	(original)
+++ doc/trunk/design/syn/S03.pod	Mon Mar 31 11:15:33 2008
@@ -12,9 +12,9 @@

Maintainer: Larry Wall <larry@wall.org>
Date: 8 Mar 2004
-  Last Modified: 17 Mar 2008
+  Last Modified: 31 Mar 2008
Number: 3
-  Version: 133
+  Version: 134

=head1 Overview

@@ -40,7 +40,7 @@
L  Concatenation     ~
X  Junctive and      &
X  Junctive or       | ^
-    L  Named unary       rand sleep abs
+    L  Named unary       sleep abs sin
N  Nonchaining infix but does <=> leg cmp .. ..^ ^.. ^..^
C  Chaining infix    != == < <= > >= eq ne lt le gt ge ~~ === eqv !eqv
L  Tight and         &&
@@ -221,7 +221,7 @@

=item *

-Function call
+Function call with parens:

a(1)

@@ -263,6 +263,14 @@
its left, so it binds tighter than comma on the left but looser than
comma on the right--see List prefix precedence below.

+=item *
+
+0-ary functions
+
+    self
+    undef
+    rand
+
=back

=head2 Method postfix precedence
@@ -568,10 +576,11 @@

+$x

-Unlike in PerlĀ_5, where C<+> is a no-op, this operator coerces
-to numeric context in PerlĀ_6.  (It coerces only the value, not the
-original variable.)  The narrowest appropriate type of C<Int>, C<Num>,
-or C<Complex> will be returned.  A string containing two integers
+Unlike in PerlĀ_5, where C<+> is a no-op, this operator coerces to
+numeric context in PerlĀ_6.  (It coerces only the value, not the
+original variable.)  For values that are not already considered
+numeric, the narrowest appropriate type of C<Int>, C<Num>, or
+C<Complex> will be returned; however, string containing two integers
separated by a C</> will be returned as a C<Rat>.  Exponential notation
and radix notations are recognized.

@@ -721,7 +730,6 @@
from a lazy exception model.)

Use of C<div> on two C<Int> values results in a ratio of the C<Rat> type.
-Integerizing a rat involves truncating its tail.

=item *

@@ -941,16 +949,48 @@

=head2 Named unary precedence

+Functions of one argument
+
+    int
+    sleep
+    abs
+    sin
+    ...         # see S29 Functions
+
+Note that, unlike in PerlĀ_5, you must use the C<.meth> forms to default
+to C<$_> in PerlĀ_6.
+
+There is no unary C<rand> function in Perl 6, though there is a C<.rand>
+method call and a 0-ary C<rand> term.
+
=over

=item *

-Functions of one argument
+C<< prefix:<int> >>

-    rand sleep abs etc.
+Coerces to type C<Int>.  Floor semantics are used for fractional
+values, including strings that appear to express fractional values.
+That is, C<int($x)> must have the same result as C<int(+$x)> in all
+cases.  All implicit conversions to integer use the same semantics.

-Note that, unlike in PerlĀ_5, you must use the C<.meth> forms to default
-to C<$_> in PerlĀ_6.
+(Note that, despite the fact that C<int> is a valid native type
+name, this function does not express conversion to that native type.
+Such subtype conversions are done automatically upon assignment to
+a subtyped container, and fail if the container cannot hold the value.)
+
+=item *
+
+C<< prefix:<sleep> >>
+
+Suspends the current thread of execution for the specified number of second
s,
+which may be fractional.
+
+=item *
+
+C<< prefix:<abs> >>
+
+Returns the absolute value of the specified argument.

=back