[ruby-core:69815] [Ruby trunk - Bug #10594] Numeric#clamp

Issue #10594 has been updated by D.E. Akers.


Hans Mackowiak wrote:
> hm might it be a good idea to have such a function directly in Comparable too?
> 
> like "x".chomp("a".."e") #=> "e"
> hm maybe have it a second way to call it with using "x".chomp("a", "e") too similar to Comparable#between?

I think your suggestions make a great deal of sense. That `#clamp` should be defined in terms of `#<=>` makes `Comparable` its natural home. Additionally, if the two-argument form were the only way to call it, the implementation would pretty much be the same as for `#between?` but with greater information density: 

```diff
 static VALUE
-cmp_between(VALUE x, VALUE min, VALUE max)
+cmp_clamp(VALUE x, VALUE min, VALUE max)
 {
-    if (RTEST(cmp_lt(x, min))) return Qfalse;
+    if (RTEST(cmp_lt(x, min))) return min;
-    if (RTEST(cmp_gt(x, max))) return Qfalse;
+    if (RTEST(cmp_gt(x, max))) return max;
-    return Qtrue;
+    return x;
 }
```

This approach does away with the potential for confusion introduced by exclusive ranges, made worse by the fact that "predecessor" is not well-defined for most `Comparable`s.

----------------------------------------
Bug #10594: Numeric#clamp
https://bugs.ruby-lang.org/issues/10594#change-53213

* Author: Chris Johnson
* Status: Open
* Priority: Normal
* Assignee: 
* ruby -v: 2.1.2
* Backport: 2.0.0: UNKNOWN, 2.1: UNKNOWN
----------------------------------------
This is basically a re-opening of the feature request of issue#4573 (https://bugs.ruby-lang.org/issues/4574), which was closed due a naming debate.

It seems the standard naming for restricting a number to a specified range is indeed 'clamp'.  (1)(2)(3)

As such, can we use Yusuke Endoh's original patch with the naming adjustments?  If so, I can provide accordingly.

Cheers.

(1) http://www.rubydoc.info/github/epitron/epitools/Numeric:clamp
(2) http://stackoverflow.com/questions/12020787/is-there-a-limit-clamp-function-in-ruby
(3) https://developer.gnome.org/glib/stable/glib-Standard-Macros.html#CLAMP:CAPS


---Files--------------------------------
num_clamp.c (427 Bytes)


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