Add the rest of the evaluator tests.

Signed-off-by: jmug <u.g.a.mariano@gmail.com>

pkg/evaluator/evaluator_test.go

@@ -51,6 +51,15 @@ func TestEvalBooleanExpression(t *testing.T) {
 		{"1 != 1", false},
 		{"1 == 2", false},
 		{"1 != 2", true},
+		{"true == true", true},
+		{"false == false", true},
+		{"true == false", false},
+		{"true != false", true},
+		{"false != true", true},
+		{"(1 < 2) == true", true},
+		{"(1 < 2) == false", false},
+		{"(1 > 2) == true", false},
+		{"(1 > 2) == false", true},
 	}
 
 	for _, tt := range tests {
@@ -70,15 +79,6 @@ func TestBangOperator(t *testing.T) {
 		{"!!true", true},
 		{"!!false", false},
 		{"!!5", true},
-		{"true == true", true},
-		{"false == false", true},
-		{"true == false", false},
-		{"true != false", true},
-		{"false != true", true},
-		{"(1 < 2) == true", true},
-		{"(1 < 2) == false", false},
-		{"(1 > 2) == true", false},
-		{"(1 > 2) == false", true},
 	}
 
 	for _, tt := range tests {
@@ -121,6 +121,7 @@ func TestReturnStatements(t *testing.T) {
 		{"return 10; 9;", 10},
 		{"return 2 * 5; 9;", 10},
 		{"9; return 2 * 5; 9;", 10},
+		{"if (10 > 1) { return 10; }", 10},
 		{
 			`
 if (10 > 1) {
@@ -133,6 +134,25 @@ if (10 > 1) {
 `,
 			10,
 		},
+		{
+			`
+let f = fn(x) {
+  return x;
+  x + 10;
+};
+f(10);`,
+			10,
+		},
+		{
+			`
+let f = fn(x) {
+   let result = x + 10;
+   return result;
+   return 10;
+};
+f(10);`,
+			20,
+		},
 	}
 
 	for _, tt := range tests {
@@ -162,10 +182,18 @@ func TestErrorHandling(t *testing.T) {
 			"true + false;",
 			"unknown operator: BOOLEAN + BOOLEAN",
 		},
+		{
+			"true + false + true + false;",
+			"unknown operator: BOOLEAN + BOOLEAN",
+		},
 		{
 			"5; true + false; 5",
 			"unknown operator: BOOLEAN + BOOLEAN",
 		},
+		{
+			`"Hello" - "World"`,
+			"unknown operator: STRING - STRING",
+		},
 		{
 			"if (10 > 1) { true + false; }",
 			"unknown operator: BOOLEAN + BOOLEAN",
@@ -186,14 +214,14 @@ if (10 > 1) {
 			"foobar",
 			"identifier not found: foobar",
 		},
-		{
-			`"Hello" - "World"`,
-			"unknown operator: STRING - STRING",
-		},
 		{
 			`{"name": "Monkey"}[fn(x) { x }];`,
 			"unusable as hash key: FUNCTION",
 		},
+		{
+			`999[1]`,
+			"index operator not supported: INTEGER",
+		},
 	}
 
 	for _, tt := range tests {
@@ -272,6 +300,35 @@ func TestFunctionApplication(t *testing.T) {
 	}
 }
 
+func TestEnclosingEnvironments(t *testing.T) {
+	input := `
+let first = 10;
+let second = 10;
+let third = 10;
+
+let ourFunction = fn(first) {
+  let second = 20;
+
+  first + second + third;
+};
+
+ourFunction(20) + first + second;`
+
+	testIntegerObject(t, testEval(input), 70)
+}
+
+func TestClosures(t *testing.T) {
+	input := `
+let newAdder = fn(x) {
+  fn(y) { x + y };
+};
+
+let addTwo = newAdder(2);
+addTwo(2);`
+
+	testIntegerObject(t, testEval(input), 4)
+}
+
 func TestStringLiteral(t *testing.T) {
 	input := `"Hello World!"`
 
@@ -303,13 +360,26 @@ func TestStringConcatenation(t *testing.T) {
 func TestBuiltinFunctions(t *testing.T) {
 	tests := []struct {
 		input    string
-		expected any
+		expected interface{}
 	}{
 		{`len("")`, 0},
 		{`len("four")`, 4},
 		{`len("hello world")`, 11},
 		{`len(1)`, "argument to `len` not supported, got INTEGER"},
 		{`len("one", "two")`, "wrong number of arguments. got=2, want=1"},
+		{`len([1, 2, 3])`, 3},
+		{`len([])`, 0},
+		{`puts("hello", "world!")`, nil},
+		{`first([1, 2, 3])`, 1},
+		{`first([])`, nil},
+		{`first(1)`, "argument to `first` must be ARRAY, got INTEGER"},
+		{`last([1, 2, 3])`, 3},
+		{`last([])`, nil},
+		{`last(1)`, "argument to `last` must be ARRAY, got INTEGER"},
+		{`rest([1, 2, 3])`, []int{2, 3}},
+		{`rest([])`, nil},
+		{`push([], 1)`, []int{1}},
+		{`push(1, 1)`, "argument to `push` must be ARRAY, got INTEGER"},
 	}
 
 	for _, tt := range tests {
@@ -318,6 +388,8 @@ func TestBuiltinFunctions(t *testing.T) {
 		switch expected := tt.expected.(type) {
 		case int:
 			testIntegerObject(t, evaluated, int64(expected))
+		case nil:
+			testNullObject(t, evaluated)
 		case string:
 			errObj, ok := evaluated.(*object.Error)
 			if !ok {
@@ -329,6 +401,22 @@ func TestBuiltinFunctions(t *testing.T) {
 				t.Errorf("wrong error message. expected=%q, got=%q",
 					expected, errObj.Message)
 			}
+		case []int:
+			array, ok := evaluated.(*object.Array)
+			if !ok {
+				t.Errorf("obj not Array. got=%T (%+v)", evaluated, evaluated)
+				continue
+			}
+
+			if len(array.Elements) != len(expected) {
+				t.Errorf("wrong num of elements. want=%d, got=%d",
+					len(expected), len(array.Elements))
+				continue
+			}
+
+			for i, expectedElem := range expected {
+				testIntegerObject(t, array.Elements[i], int64(expectedElem))
+			}
 		}
 	}
 }
@@ -495,21 +583,13 @@ func TestHashIndexExpressions(t *testing.T) {
 		}
 	}
 }
-
-func testNullObject(t *testing.T, obj object.Object) bool {
-	if obj != _NULL {
-		t.Errorf("object is not NULL. got=%T (%+v)", obj, obj)
-		return false
-	}
-	return true
-}
-
 func testEval(input string) object.Object {
 	l := lexer.New(input)
 	p := parser.New(l)
 	program := p.ParseProgram()
+	env := object.NewEnvironment()
 
-	return Eval(program, object.NewEnvironment())
+	return Eval(program, env)
 }
 
 func testIntegerObject(t *testing.T, obj object.Object, expected int64) bool {
@@ -540,3 +620,11 @@ func testBooleanObject(t *testing.T, obj object.Object, expected bool) bool {
 	}
 	return true
 }
+
+func testNullObject(t *testing.T, obj object.Object) bool {
+	if obj != _NULL {
+		t.Errorf("object is not NULL. got=%T (%+v)", obj, obj)
+		return false
+	}
+	return true
+}