comprehension spec

spec/comprehension_spec.moon

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+
+describe "comprehension", ->
+  it "should double every number", ->
+    input = {1,2,3,4,5,6}
+    output_1 = [i * 2 for _, i in pairs input ]
+    output_2 = [i * 2 for i in *input ]
+
+    assert.same output_1, {2,4,6,8,10,12}
+
+  it "should create a slice", ->
+    input = {1,2,3,4,5,6}
+
+    slice_1 = [i for i in *input[1,3]]
+    slice_2 = [i for i in *input[,3]]
+
+    slice_3 = [i for i in *input[3,]]
+    slice_4 = [i for i in *input[,]]
+
+    slice_5 = [i for i in *input[,,2]]
+    slice_6 = [i for i in *input[2,,2]]
+
+    assert.same slice_1, {1,2,3}
+    assert.same slice_1, slice_2
+    assert.same slice_3, {3,4,5,6}
+    assert.same slice_4, input
+
+    assert.same slice_5, {1,3,5}
+    assert.same slice_6, {2,4,6}
+
+  it "should be able to assign to self", ->
+    input = {1,2,3,4}
+    output = input
+    output = [i * 2 for i in *output]
+
+    assert.same input, {1,2,3,4}
+    assert.same output, {2,4,6,8}
+