Implement Array#nitems(). Second try.

Signed-off-by: Ted Reed <ted.reed@gmail.com>

Rakefile

@@ -277,6 +277,7 @@ namespace :test do |ns|
         test "array/intersection.t"
         test "array/join.t"
         test "array/mathop.t"
+        test "array/nitems.t"
         test "array/pop.t"
         test "array/push.t"
         test "array/reject.t"
@@ -290,7 +291,7 @@ namespace :test do |ns|
         test "array/values_at.t"
         test "array/warray.t"
 
-        task :all => [:array, :assign, :at, :clear, :collect, :compact, :concat, :delete, :empty, :equals, :fetch, :fill, :first, :flatten, :grep, :include, :index, :insert, :intersection, :join, :mathop, :pop, :push, :reject, :replace, :reverse, :shift, :slice, :sort, :to_s, :uniq, :values_at, :warray]
+        task :all => [:array, :assign, :at, :clear, :collect, :compact, :concat, :delete, :empty, :equals, :fetch, :fill, :first, :flatten, :grep, :include, :index, :insert, :intersection, :join, :mathop, :nitems, :pop, :push, :reject, :replace, :reverse, :shift, :slice, :sort, :to_s, :uniq, :values_at, :warray]
     end
 
     namespace :file do 

src/classes/Array.pir

@@ -1640,6 +1640,22 @@ The zip operator.
 # TODO: pass warning
 .end
 
+.sub 'nitems' :method
+    .local int count
+    .local pmc it
+    count = 0
+    it = iter self
+  iter_loop:
+    unless it goto done
+    $P0 = shift it
+    $I0 = isa $P0, "NilClass"
+    if $I0 goto iter_loop
+    inc count
+    goto iter_loop
+  done:
+    .return ( count )
+.end
+
 .sub '_cmp' :vtable('cmp') :method
     .param pmc other
     .local int i, len, result

t/array/nitems

@@ -0,0 +1,16 @@
+require 'Test'
+include Test
+plan 4
+
+a = [ ]
+is a.nitems(), 0, 'nitems, no items'
+
+a = [ 1, 2, 3, 4 ]
+is a.nitems(), 4, 'nitems, 4 non-nil items'
+
+a = [ 1, 2, 3, nil ]
+is a.nitems(), 3, 'nitems, 3 non-nil items, 1 nil'
+
+a = [ nil, nil, nil, nil ]
+is a.nitems(), 0, 'nitems, 4 nil items'
+