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StaticArray improvements (map_with_index!) #3356

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StaticArray improvements (map_with_index!) #3356

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13 changes: 11 additions & 2 deletions spec/std/static_array_spec.cr
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Original file line number Diff line number Diff line change
Expand Up @@ -101,22 +101,31 @@ describe "StaticArray" do
end
end

it "reverse" do
it "reverse!" do
a = StaticArray(Int32, 3).new { |i| i + 1 }
a.reverse!
a[0].should eq(3)
a[1].should eq(2)
a[2].should eq(1)
end

it "maps!" do
it "map!" do
a = StaticArray(Int32, 3).new { |i| i + 1 }
a.map! { |i| i + 1 }
a[0].should eq(2)
a[1].should eq(3)
a[2].should eq(4)
end

it "map_with_index!" do
a = StaticArray(Int32, 3).new { |i| i + 1 }
a.map_with_index! { |e, i| i * 2 }
a[0].should eq(0)
a[1].should eq(2)
a[2].should eq(4)
a.should be_a(StaticArray(Int32, 3))
end

it "updates value" do
a = StaticArray(Int32, 3).new { |i| i + 1 }
a.update(1) { |x| x * 2 }
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11 changes: 11 additions & 0 deletions src/static_array.cr
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Expand Up @@ -163,6 +163,17 @@ struct StaticArray(T, N)
self
end

# Like `map`, but the block gets passed both the element and its index.
def map_with_index!
i = 0
to_unsafe.map!(size) do |e|
res = yield e, i
i += 1
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Incrementing i after yield would allow to drop i - 1 part which seems bit odd... just a thought :)

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@Nephos Nephos Sep 26, 2016 •
edited
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map! do |e|
  res = yield e, i
  i += 1
  res
end

?

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done

res
end
self
end

# Reverses the elements of this array in-place, then returns `self`
#
# ```
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