Re: r27605 - docs/Perl6/Spec/S32-setting-library

[James Cloos]

lwall + enum TrigBase is export Radians Degrees Gradians Circles;

Is Circles of much value?

I can see Semicircles, since that would make the range (-1,1] or [-1,1).
But a range of [0,1) or (0,1] seems *much* less useful.

Or am I missing an obvious use case?

-JimC
-- 
James Cloos cl...@jhcloos.com OpenPGP: 1024D/ED7DAEA6

Re: r27605 - docs/Perl6/Spec/S32-setting-library

[Geoffrey Broadwell]

On Sat, 2009-07-18 at 21:22 -0400, James Cloos wrote:
 lwall + enum TrigBase is export Radians Degrees Gradians Circles;
 
 Is Circles of much value?
 
 I can see Semicircles, since that would make the range (-1,1] or [-1,1).
 But a range of [0,1) or (0,1] seems *much* less useful.
 
 Or am I missing an obvious use case?

With Circles, simple int/frac always gets you a count of full rotations
and an angle always between 0 and one full rotation.  Seems useful to
me.

Semicircles sounds useful as well, for the reason you state above.


-'f

r27605 - docs/Perl6/Spec/S32-setting-library

[pugs-commits]

Author: lwall
Date: 2009-07-18 18:44:26 +0200 (Sat, 18 Jul 2009)
New Revision: 27605

Modified:
   docs/Perl6/Spec/S32-setting-library/Numeric.pod
Log:
[Numeric] kill :Trig tag, always include trig functions.
Replace stupid string args with an enum.
Default to lexical constant $?TRIGBASE.


Modified: docs/Perl6/Spec/S32-setting-library/Numeric.pod
===
--- docs/Perl6/Spec/S32-setting-library/Numeric.pod 2009-07-18 14:42:37 UTC 
(rev 27604)
+++ docs/Perl6/Spec/S32-setting-library/Numeric.pod 2009-07-18 16:44:26 UTC 
(rev 27605)
@@ -19,8 +19,8 @@
 
 Created: 19 Mar 2009 extracted from S29-functions.pod
 
-Last Modified: 19 Feb 2009
-Version: 1
+Last Modified: 18 Jul 2009
+Version: 2
 
 The document is a draft.
 
@@ -228,16 +228,19 @@
 
 =back
 
-=head2 The :Trig tag
+=head2 Trigonometric functions
 
-The following are also defined in CNum but not exported without a C:Trig
-tag.  (Which installs their names into CNum::Trig, as it happens.)
+The following are also defined in CNum.  The trig functions
+depend on the current (lexically scoped) trig base:
 
+ enum TrigBase is export Radians Degrees Gradians Circles;
+ constant $?TRIGBASE = Radians;
+
 =over 4
 
 =item IStandard Trig Functions
 
- Num multi method func ( Num  $x: $base = 'radians' ) is export(:Trig)
+ Num multi method func ( Num  $x: TrigBase $base = $?TRIGBASE ) is export
 
 where Ifunc is one of:
 sin, cos, tan, asin, acos, atan, sec, cosec, cotan, asec, acosec,
@@ -249,20 +252,18 @@
 Option C$base is used to declare how you measure your angles.
 Given the value of an arc representing a single full revolution.
 
- $base  Result
-    ---
- /:i ^r/Radians  (2*pi)
- /:i ^d/Degrees  (360)
- /:i ^g/Gradians (400)
- NumUnits of 1 revolution.
+ $base   Subdivisions of circle
+ --
+ Radians 2*pi
+ Degrees 360
+ Gradians400
+ Circles 1
 
-Note that module currying can be used within a lexical scope to specify
-a consistent base so you don't have to supply it with every call:
+To change the base within your own lexical scope, it suffices to redefine the
+compiler constant:
 
- my module Trig ::= Num::Trig.assuming(:basedegrees);
+ constant $?TRIGBASE = Degrees;
 
-This overrides the default of radians.
-
 =item atan2
 
  our Num multi method atan2 ( Num $y: Num $x = 1 )
@@ -277,3 +278,5 @@
 
 Please post errors and feedback to perl6-language.  If you are making
 a general laundry list, please separate messages by topic.
+
+=for vim:set expandtab sw=4: