Moved register state to scopes

src/build/token/Count.go

@@ -0,0 +1,14 @@
+package token
+
+// Count counts how often the given token appears in the token list.
+func Count(tokens List, kind Kind, name string) int {
+	count := 0
+
+	for _, t := range tokens {
+		if t.Kind == Identifier && t.Text() == name {
+			count++
+		}
+	}
+
+	return count
+}

src/build/token/Token_test.go

@@ -95,6 +95,14 @@ func TestArray(t *testing.T) {
 	})
 }
 
+func TestCount(t *testing.T) {
+	tokens := token.Tokenize([]byte(`a b b c c c`))
+	assert.Equal(t, token.Count(tokens, token.Identifier, "a"), 1)
+	assert.Equal(t, token.Count(tokens, token.Identifier, "b"), 2)
+	assert.Equal(t, token.Count(tokens, token.Identifier, "c"), 3)
+	assert.Equal(t, token.Count(tokens, token.Identifier, "d"), 0)
+}
+
 func TestNewline(t *testing.T) {
 	tokens := token.Tokenize([]byte("\n\n"))
 	assert.DeepEqual(t, tokens, token.List{