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 <[EMAIL PROTECTED]>
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 @@
+$x
-Unlike in Perl 5, where C<+> is a no-op, this operator coerces
-to numeric context in Perl 6. (It coerces only the value, not the
-original variable.) The narrowest appropriate type of C<Int>, C<Num>,
-or C<Complex> will be returned. A string containing two integers
+Unlike in Perl 5, where C<+> is a no-op, this operator coerces to
+numeric context in Perl 6. (It coerces only the value, not the
+original variable.) For values that are not already considered
+numeric, the narrowest appropriate type of C<Int>, C<Num>, or
+C<Complex> will be returned; however, string containing two integers
separated by a C</> will be returned as a C<Rat>. Exponential notation
and radix notations are recognized.
@@ -721,7 +730,6 @@
from a lazy exception model.)
Use of C<div> on two C<Int> values results in a ratio of the C<Rat> type.
-Integerizing a rat involves truncating its tail.
=item *
@@ -941,16 +949,48 @@
=head2 Named unary precedence
+Functions of one argument
+
+ int
+ sleep
+ abs
+ sin
+ ... # see S29 Functions
+
+Note that, unlike in Perl 5, you must use the C<.meth> forms to default
+to C<$_> in Perl 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 Perl 5, you must use the C<.meth> forms to default
-to C<$_> in Perl 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 seconds,
+which may be fractional.
+
+=item *
+
+C<< prefix:<abs> >>
+
+Returns the absolute value of the specified argument.
=back
