Add Float#round method.

goby-lang · Apr 21, 2020 · 86f94a0 · 86f94a0
1 parent 77e3229
commit 86f94a0
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Showing 2 changed files with 59 additions and 1 deletion.
diff --git a/vm/float.go b/vm/float.go
@@ -436,6 +436,40 @@ var builtinFloatInstanceMethods = []*BuiltinMethodObject{
 			return toBooleanObject(r.value < 0.0)
 		},
 	},
+	{
+		//  Rounds float to a given precision in decimal digits (default 0 digits)
+		//
+		// ```Ruby
+		// 1.115.round  # => 1
+		// 1.115.round(1)  # => 1.1
+		// 1.115.round(2)  # => 1.12
+		// -1.115.round  # => -1
+		// -1.115.round(1)  # => -1.1
+		// -1.115.round(2)  # => -1.12
+		// ```
+		// @return [Integer]
+		Name: "round",
+		Fn: func(receiver Object, sourceLine int, t *Thread, args []Object, blockFrame *normalCallFrame) Object {
+			var precision int
+
+			if len(args) > 1 {
+				return t.vm.InitErrorObject(errors.ArgumentError, sourceLine, "Expect 0 or 1 argument. got=%v", strconv.Itoa(len(args)))
+			} else if len(args) == 1 {
+				int, ok := args[0].(*IntegerObject)
+
+				if !ok {
+					return t.vm.InitErrorObject(errors.TypeError, sourceLine, errors.WrongArgumentTypeFormat, classes.IntegerClass, args[0].Class().Name)
+				}
+
+				precision = int.value
+			}
+
+			f := receiver.(*FloatObject).floatValue()
+			n := math.Pow10(precision)
+
+			return t.vm.initFloatObject(math.Round(f*n) / n)
+		},
+	},
 }
 
 // Internal functions ===================================================

diff --git a/vm/float_test.go b/vm/float_test.go
@@ -337,6 +337,7 @@ func TestFloatNumberOfDigit(t *testing.T) {
 		v.checkSP(t, i, 1)
 	}
 }
+
 // API tests
 
 func TestFloatAbs(t *testing.T) {
@@ -482,6 +483,30 @@ func TestFloatPositive(t *testing.T) {
 	}
 }
 
+func TestFloatRound(t *testing.T) {
+	tests := []struct {
+		input    string
+		expected interface{}
+	}{
+		{"1.115.round", 1.0},
+		{"1.115.round(1)", 1.1},
+		{"1.115.round(2)", 1.12},
+		{"-1.115.round", -1.0},
+		{"-1.115.round(1)", -1.1},
+		{"-1.115.round(2)", -1.12},
+		{"1.115.round(-1)", 0.0},
+		{"-1.115.round(-1)", 0.0},
+	}
+
+	for i, tt := range tests {
+		v := initTestVM()
+		evaluated := v.testEval(t, tt.input, getFilename())
+		VerifyExpected(t, i, evaluated, tt.expected)
+		v.checkCFP(t, i, 0)
+		v.checkSP(t, i, 1)
+	}
+}
+
 func TestFloatZero(t *testing.T) {
 	tests := []struct {
 		input    string
@@ -499,4 +524,3 @@ func TestFloatZero(t *testing.T) {
 		v.checkSP(t, i, 1)
 	}
 }
-