Add tons of builtin helpers and array operations.

compiler/compiler_test.go

@@ -879,11 +879,11 @@ func TestBuiltins(t *testing.T) {
             `,
 			expectedConstants: []interface{}{1},
 			expectedInstructions: []code.Instructions{
-				code.Make(code.OpGetBuiltin, 7),
+				code.Make(code.OpGetBuiltin, 10),
 				code.Make(code.OpArray, 0),
 				code.Make(code.OpCall, 1),
 				code.Make(code.OpPop),
-				code.Make(code.OpGetBuiltin, 10),
+				code.Make(code.OpGetBuiltin, 14),
 				code.Make(code.OpArray, 0),
 				code.Make(code.OpConstant, 0),
 				code.Make(code.OpCall, 2),
@@ -894,7 +894,7 @@ func TestBuiltins(t *testing.T) {
 			input: `fn() { return len([]) }`,
 			expectedConstants: []interface{}{
 				[]code.Instructions{
-					code.Make(code.OpGetBuiltin, 7),
+					code.Make(code.OpGetBuiltin, 10),
 					code.Make(code.OpArray, 0),
 					code.Make(code.OpCall, 1),
 					code.Make(code.OpReturn),

evaluator/evaluator.go

@@ -306,8 +306,29 @@ func evalIntegerPrefixOperatorExpression(operator string, right object.Object) o
 func evalInfixExpression(operator string, left, right object.Object) object.Object {
 	switch {
 
+	// {"a": 1} + {"b": 2}
+	case operator == "+" && left.Type() == object.HASH_OBJ && right.Type() == object.HASH_OBJ:
+		leftVal := left.(*object.Hash).Pairs
+		rightVal := right.(*object.Hash).Pairs
+		pairs := make(map[object.HashKey]object.HashPair)
+		for k, v := range leftVal {
+			pairs[k] = v
+		}
+		for k, v := range rightVal {
+			pairs[k] = v
+		}
+		return &object.Hash{Pairs: pairs}
+
+	// [1] + [2]
+	case operator == "+" && left.Type() == object.ARRAY_OBJ && right.Type() == object.ARRAY_OBJ:
+		leftVal := left.(*object.Array).Elements
+		rightVal := right.(*object.Array).Elements
+		elements := make([]object.Object, len(leftVal)+len(rightVal))
+		elements = append(leftVal, rightVal...)
+		return &object.Array{Elements: elements}
+
 	// [1] * 3
-	case left.Type() == object.ARRAY_OBJ && right.Type() == object.INTEGER_OBJ:
+	case operator == "*" && left.Type() == object.ARRAY_OBJ && right.Type() == object.INTEGER_OBJ:
 		leftVal := left.(*object.Array).Elements
 		rightVal := int(right.(*object.Integer).Value)
 		elements := leftVal
@@ -316,7 +337,7 @@ func evalInfixExpression(operator string, left, right object.Object) object.Obje
 		}
 		return &object.Array{Elements: elements}
 	// 3 * [1]
-	case left.Type() == object.INTEGER_OBJ && right.Type() == object.ARRAY_OBJ:
+	case operator == "*" && left.Type() == object.INTEGER_OBJ && right.Type() == object.ARRAY_OBJ:
 		leftVal := int(left.(*object.Integer).Value)
 		rightVal := right.(*object.Array).Elements
 		elements := rightVal
@@ -326,12 +347,12 @@ func evalInfixExpression(operator string, left, right object.Object) object.Obje
 		return &object.Array{Elements: elements}
 
 	// " " * 4
-	case left.Type() == object.STRING_OBJ && right.Type() == object.INTEGER_OBJ:
+	case operator == "*" && left.Type() == object.STRING_OBJ && right.Type() == object.INTEGER_OBJ:
 		leftVal := left.(*object.String).Value
 		rightVal := right.(*object.Integer).Value
 		return &object.String{Value: strings.Repeat(leftVal, int(rightVal))}
 	// 4 * " "
-	case left.Type() == object.INTEGER_OBJ && right.Type() == object.STRING_OBJ:
+	case operator == "*" && left.Type() == object.INTEGER_OBJ && right.Type() == object.STRING_OBJ:
 		leftVal := left.(*object.Integer).Value
 		rightVal := right.(*object.String).Value
 		return &object.String{Value: strings.Repeat(rightVal, int(leftVal))}

evaluator/evaluator_test.go

@@ -182,27 +182,27 @@ func TestErrorHandling(t *testing.T) {
 	}{
 		{
 			"5 + true;",
-			"type mismatch: INTEGER + BOOLEAN",
+			"type mismatch: int + bool",
 		},
 		{
 			"5 + true; 5;",
-			"type mismatch: INTEGER + BOOLEAN",
+			"type mismatch: int + bool",
 		},
 		{
 			"-true",
-			"unknown operator: -BOOLEAN",
+			"unknown operator: -bool",
 		},
 		{
 			"true + false;",
-			"unknown operator: BOOLEAN + BOOLEAN",
+			"unknown operator: bool + bool",
 		},
 		{
 			"5; true + false; 5",
-			"unknown operator: BOOLEAN + BOOLEAN",
+			"unknown operator: bool + bool",
 		},
 		{
 			"if (10 > 1) { true + false; }",
-			"unknown operator: BOOLEAN + BOOLEAN",
+			"unknown operator: bool + bool",
 		},
 		{
 			`
@@ -214,7 +214,7 @@ func TestErrorHandling(t *testing.T) {
 				  return 1;
 				}
 				`,
-			"unknown operator: BOOLEAN + BOOLEAN",
+			"unknown operator: bool + bool",
 		},
 		{
 			"foobar",
@@ -222,11 +222,11 @@ func TestErrorHandling(t *testing.T) {
 		},
 		{
 			`"Hello" - "World"`,
-			"unknown operator: STRING - STRING",
+			"unknown operator: str - str",
 		},
 		{
 			`{"name": "Monkey"}[fn(x) { x }];`,
-			"unusable as hash key: FUNCTION",
+			"unusable as hash key: fn",
 		},
 	}
 
@@ -395,21 +395,21 @@ func TestBuiltinFunctions(t *testing.T) {
 		{`len("")`, 0},
 		{`len("four")`, 4},
 		{`len("hello world")`, 11},
-		{`len(1)`, errors.New("argument to `len` not supported, got INTEGER")},
+		{`len(1)`, errors.New("argument to `len` not supported, got int")},
 		{`len("one", "two")`, errors.New("wrong number of arguments. got=2, want=1")},
 		{`len("∑")`, 1},
 		{`len([1, 2, 3])`, 3},
 		{`len([])`, 0},
 		{`first([1, 2, 3])`, 1},
 		{`first([])`, nil},
-		{`first(1)`, errors.New("argument to `first` must be ARRAY, got INTEGER")},
+		{`first(1)`, errors.New("argument to `first` must be array, got int")},
 		{`last([1, 2, 3])`, 3},
 		{`last([])`, nil},
-		{`last(1)`, errors.New("argument to `last` must be ARRAY, got INTEGER")},
+		{`last(1)`, errors.New("argument to `last` must be array, got int")},
 		{`rest([1, 2, 3])`, []int{2, 3}},
 		{`rest([])`, nil},
 		{`push([], 1)`, []int{1}},
-		{`push(1, 1)`, errors.New("argument to `push` must be ARRAY, got INTEGER")},
+		{`push(1, 1)`, errors.New("argument to `push` must be array, got int")},
 		{`print("Hello World")`, nil},
 		{`input()`, ""},
 		{`pop([])`, errors.New("cannot pop from an empty array")},
@@ -500,6 +500,24 @@ func TestArrayDuplication(t *testing.T) {
 	testIntegerObject(t, result.Elements[2], 1)
 }
 
+func TestArrayMerging(t *testing.T) {
+	input := "[1] + [2]"
+
+	evaluated := testEval(input)
+	result, ok := evaluated.(*object.Array)
+	if !ok {
+		t.Fatalf("object is not Array. got=%T (%+v)", evaluated, evaluated)
+	}
+
+	if len(result.Elements) != 2 {
+		t.Fatalf("array has wrong num of elements. got=%d",
+			len(result.Elements))
+	}
+
+	testIntegerObject(t, result.Elements[0], 1)
+	testIntegerObject(t, result.Elements[1], 2)
+}
+
 func TestArrayIndexExpressions(t *testing.T) {
 	tests := []struct {
 		input    string
@@ -599,6 +617,33 @@ func TestHashLiterals(t *testing.T) {
 	}
 }
 
+func TestHashMerging(t *testing.T) {
+	input := `{"a": 1} + {"b": 2}`
+	evaluated := testEval(input)
+	result, ok := evaluated.(*object.Hash)
+	if !ok {
+		t.Fatalf("Eval didn't return Hash. got=%T (%+v)", evaluated, evaluated)
+	}
+
+	expected := map[object.HashKey]int64{
+		(&object.String{Value: "a"}).HashKey(): 1,
+		(&object.String{Value: "b"}).HashKey(): 2,
+	}
+
+	if len(result.Pairs) != len(expected) {
+		t.Fatalf("Hash has wrong num of pairs. got=%d", len(result.Pairs))
+	}
+
+	for expectedKey, expectedValue := range expected {
+		pair, ok := result.Pairs[expectedKey]
+		if !ok {
+			t.Errorf("no pair for given key in Pairs")
+		}
+
+		testIntegerObject(t, pair.Value, expectedValue)
+	}
+}
+
 func TestHashSelectorExpressions(t *testing.T) {
 	tests := []struct {
 		input    string

foo.monkey

@@ -0,0 +1,3 @@
+#!./monkey-lang
+
+print(args())

main.go

@@ -70,6 +70,11 @@ func main() {
 
 	args := flag.Args()
 
+	copy(object.Arguments, args)
+	object.StandardInput = os.Stdin
+	object.StandardOutput = os.Stdout
+	object.ExitFunction = os.Exit
+
 	if compile {
 		if len(args) < 1 {
 			log.Fatal("no source file given to compile")

object/builtin_args.go

@@ -0,0 +1,10 @@
+package object
+
+// Args  ...
+func Args(args ...Object) Object {
+	elements := make([]Object, len(Arguments))
+	for i, arg := range Arguments {
+		elements[i] = &String{Value: arg}
+	}
+	return &Array{Elements: elements}
+}

object/builtin_exit.go

@@ -1,17 +1,17 @@
 package object
 
-import "os"
-
 // Exit ...
 func Exit(args ...Object) Object {
+	var status int
 	if len(args) == 1 {
 		if args[0].Type() != INTEGER_OBJ {
 			return newError("argument to `exit` must be INTEGER, got %s",
 				args[0].Type())
 		}
-		os.Exit(int(args[0].(*Integer).Value))
+		status = int(args[0].(*Integer).Value)
-	} else {
-		os.Exit(0)
 	}
+
+	ExitFunction(status)
+
 	return nil
 }

object/builtin_find.go

@@ -0,0 +1,34 @@
+package object
+
+import (
+	"strings"
+)
+
+// Find ...
+func Find(args ...Object) Object {
+	if len(args) != 2 {
+		return newError("wrong number of arguments. got=%d, want=2",
+			len(args))
+	}
+
+	if haystack, ok := args[0].(*String); ok {
+		if needle, ok := args[1].(*String); ok {
+			index := strings.Index(haystack.Value, needle.Value)
+			return &Integer{Value: int64(index)}
+		} else {
+			return newError("expected arg #2 to be `str` got got=%T", args[1])
+		}
+	} else if haystack, ok := args[0].(*Array); ok {
+		needle := args[1]
+		index := -1
+		for i, el := range haystack.Elements {
+			if cmp, ok := el.(Comparable); ok && cmp.Equal(needle) {
+				index = i
+				break
+			}
+		}
+		return &Integer{Value: int64(index)}
+	} else {
+		return newError("expected arg #1 to be `str` or `array` got got=%T", args[0])
+	}
+}

object/builtin_first.go

@@ -7,7 +7,7 @@ func First(args ...Object) Object {
 			len(args))
 	}
 	if args[0].Type() != ARRAY_OBJ {
-		return newError("argument to `first` must be ARRAY, got %s",
+		return newError("argument to `first` must be array, got %s",
 			args[0].Type())
 	}
 

object/builtin_join.go

@@ -0,0 +1,27 @@
+package object
+
+import (
+	"strings"
+)
+
+// Join ...
+func Join(args ...Object) Object {
+	if len(args) != 2 {
+		return newError("wrong number of arguments. got=%d, want=1",
+			len(args))
+	}
+
+	if arr, ok := args[0].(*Array); ok {
+		if sep, ok := args[1].(*String); ok {
+			a := make([]string, len(arr.Elements))
+			for i, el := range arr.Elements {
+				a[i] = el.String()
+			}
+			return &String{Value: strings.Join(a, sep.Value)}
+		} else {
+			return newError("expected arg #2 to be `str` got got=%T", args[1])
+		}
+	} else {
+		return newError("expected arg #1 to be `array` got got=%T", args[0])
+	}
+}

object/builtin_last.go

@@ -7,7 +7,7 @@ func Last(args ...Object) Object {
 			len(args))
 	}
 	if args[0].Type() != ARRAY_OBJ {
-		return newError("argument to `last` must be ARRAY, got %s",
+		return newError("argument to `last` must be array, got %s",
 			args[0].Type())
 	}
 

object/builtin_lower.go

@@ -0,0 +1,16 @@
+package object
+
+import "strings"
+
+// Lower ...
+func Lower(args ...Object) Object {
+	if len(args) != 1 {
+		return newError("wrong number of arguments. got=%d, want=1",
+			len(args))
+	}
+
+	if str, ok := args[0].(*String); ok {
+		return &String{Value: strings.ToLower(str.Value)}
+	}
+	return newError("expected `str` argument to `lower` got=%T", args[0])
+}

object/builtin_pop.go

@@ -7,7 +7,7 @@ func Pop(args ...Object) Object {
 			len(args))
 	}
 	if args[0].Type() != ARRAY_OBJ {
-		return newError("argument to `pop` must be ARRAY, got %s",
+		return newError("argument to `pop` must be array, got %s",
 			args[0].Type())
 	}
 

object/builtin_push.go

@@ -7,7 +7,7 @@ func Push(args ...Object) Object {
 			len(args))
 	}
 	if args[0].Type() != ARRAY_OBJ {
-		return newError("argument to `push` must be ARRAY, got %s",
+		return newError("argument to `push` must be array, got %s",
 			args[0].Type())
 	}
 

object/builtin_rest.go

@@ -7,7 +7,7 @@ func Rest(args ...Object) Object {
 			len(args))
 	}
 	if args[0].Type() != ARRAY_OBJ {
-		return newError("argument to `rest` must be ARRAY, got %s",
+		return newError("argument to `rest` must be array, got %s",
 			args[0].Type())
 	}
 

object/builtin_split.go

@@ -0,0 +1,36 @@
+package object
+
+import (
+	"strings"
+)
+
+// Split ...
+func Split(args ...Object) Object {
+	if len(args) < 1 {
+		return newError("wrong number of arguments. got=%d, want=1",
+			len(args))
+	}
+
+	if obj, ok := args[0].(*String); ok {
+		var sep string
+
+		s := obj.Value
+
+		if len(args) == 2 {
+			if obj, ok := args[1].(*String); ok {
+				sep = obj.Value
+			} else {
+				return newError("expected arg #2 to be `str` got=%T", args[1])
+			}
+		}
+
+		tokens := strings.Split(s, sep)
+		elements := make([]Object, len(tokens))
+		for i, token := range tokens {
+			elements[i] = &String{Value: token}
+		}
+		return &Array{Elements: elements}
+	} else {
+		return newError("expected arg #1 to be `str` got got=%T", args[0])
+	}
+}

object/builtin_typeof.go

@@ -0,0 +1,10 @@
+package object
+
+// TypeOf  ...
+func TypeOf(args ...Object) Object {
+	if len(args) != 1 {
+		return newError("wrong number of arguments. got=%d, want=1", len(args))
+	}
+
+	return &String{Value: string(args[0].Type())}
+}

object/builtin_upper.go

@@ -0,0 +1,16 @@
+package object
+
+import "strings"
+
+// Upper ...
+func Upper(args ...Object) Object {
+	if len(args) != 1 {
+		return newError("wrong number of arguments. got=%d, want=1",
+			len(args))
+	}
+
+	if str, ok := args[0].(*String); ok {
+		return &String{Value: strings.ToUpper(str.Value)}
+	}
+	return newError("expected `str` argument to `upper` got=%T", args[0])
+}

object/builtins.go

@@ -20,6 +20,13 @@ var Builtins = map[string]*Builtin{
 	"bool":   {Name: "bool", Fn: Bool},
 	"int":    {Name: "int", Fn: Int},
 	"str":    {Name: "str", Fn: Str},
+	"typeof": {Name: "typeof", Fn: TypeOf},
+	"args":   {Name: "args", Fn: Args},
+	"lower":  {Name: "lower", Fn: Lower},
+	"upper":  {Name: "upper", Fn: Upper},
+	"join":   {Name: "join", Fn: Join},
+	"split":  {Name: "split", Fn: Split},
+	"find":   {Name: "find", Fn: Find},
 }
 
 // BuiltinsIndex ...

object/object.go

@@ -12,20 +12,27 @@ import (
 type ObjectType string
 
 const (
-	INTEGER_OBJ           = "INTEGER"
+	INTEGER_OBJ           = "int"
-	BOOLEAN_OBJ           = "BOOLEAN"
+	BOOLEAN_OBJ           = "bool"
-	NULL_OBJ              = "NULL"
+	NULL_OBJ              = "null"
-	RETURN_VALUE_OBJ      = "RETURN_VALUE"
+	RETURN_VALUE_OBJ      = "return"
-	ERROR_OBJ             = "ERROR"
+	ERROR_OBJ             = "error"
-	FUNCTION_OBJ          = "FUNCTION"
+	FUNCTION_OBJ          = "fn"
-	STRING_OBJ            = "STRING"
+	STRING_OBJ            = "str"
-	BUILTIN_OBJ           = "BUILTIN"
+	BUILTIN_OBJ           = "builtin"
-	ARRAY_OBJ             = "ARRAY"
+	ARRAY_OBJ             = "array"
-	HASH_OBJ              = "HASH"
+	HASH_OBJ              = "hash"
 	COMPILED_FUNCTION_OBJ = "COMPILED_FUNCTION"
-	CLOSURE_OBJ           = "CLOSURE"
+	CLOSURE_OBJ           = "closure"
 )
 
+// Comparable is the interface for comparing two Object and their underlying
+// values. It is the responsibility of the caller (left) to check for types.
+// Returns `true` iif the types and values are identical, `false` otherwise.
+type Comparable interface {
+	Equal(other Object) bool
+}
+
 // Immutable is the interface for all immutable objects which must implement
 // the Clone() method used by binding names to values.
 type Immutable interface {
@@ -60,6 +67,12 @@ func (i *Integer) Clone() Object {
 func (i *Integer) String() string {
 	return i.Inspect()
 }
+func (i *Integer) Equal(other Object) bool {
+	if obj, ok := other.(*Integer); ok {
+		return i.Value == obj.Value
+	}
+	return false
+}
 
 type Boolean struct {
 	Value bool
@@ -77,6 +90,12 @@ func (b *Boolean) Clone() Object {
 func (b *Boolean) String() string {
 	return b.Inspect()
 }
+func (b *Boolean) Equal(other Object) bool {
+	if obj, ok := other.(*Boolean); ok {
+		return b.Value == obj.Value
+	}
+	return false
+}
 
 type Null struct{}
 
@@ -89,6 +108,10 @@ func (n *Null) Inspect() string {
 func (n *Null) String() string {
 	return n.Inspect()
 }
+func (n *Null) Equal(other Object) bool {
+	_, ok := other.(*Null)
+	return ok
+}
 
 type ReturnValue struct {
 	Value Object
@@ -167,6 +190,12 @@ func (s *String) Clone() Object {
 func (s *String) String() string {
 	return s.Value
 }
+func (s *String) Equal(other Object) bool {
+	if obj, ok := other.(*String); ok {
+		return s.Value == obj.Value
+	}
+	return false
+}
 
 type BuiltinFunction func(args ...Object) Object
 
@@ -209,6 +238,25 @@ func (ao *Array) Inspect() string {
 func (ao *Array) String() string {
 	return ao.Inspect()
 }
+func (ao *Array) Equal(other Object) bool {
+	if obj, ok := other.(*Array); ok {
+		if len(ao.Elements) != len(obj.Elements) {
+			return false
+		}
+		for i, el := range ao.Elements {
+			cmp, ok := el.(Comparable)
+			if !ok {
+				return false
+			}
+			if !cmp.Equal(obj.Elements[i]) {
+				return false
+			}
+		}
+
+		return true
+	}
+	return false
+}
 
 type HashKey struct {
 	Type  ObjectType
@@ -271,6 +319,31 @@ func (h *Hash) Inspect() string {
 func (h *Hash) String() string {
 	return h.Inspect()
 }
+func (h *Hash) Equal(other Object) bool {
+	if obj, ok := other.(*Hash); ok {
+		if len(h.Pairs) != len(obj.Pairs) {
+			return false
+		}
+		for _, pair := range h.Pairs {
+			left := pair.Value
+			hashed := left.(Hashable)
+			right, ok := obj.Pairs[hashed.HashKey()]
+			if !ok {
+				return false
+			}
+			cmp, ok := left.(Comparable)
+			if !ok {
+				return false
+			}
+			if !cmp.Equal(right.Value) {
+				return false
+			}
+		}
+
+		return true
+	}
+	return false
+}
 
 func (cf *CompiledFunction) Type() ObjectType {
 	return COMPILED_FUNCTION_OBJ

object/state.go

@@ -0,0 +1,10 @@
+package object
+
+import "io"
+
+var (
+	Arguments      []string
+	StandardInput  io.Reader
+	StandardOutput io.Writer
+	ExitFunction   func(int)
+)

vm/vm.go

@@ -527,8 +527,29 @@ func (vm *VM) executeBinaryOperation(op code.Opcode) error {
 
 	switch {
 
+	// {"a": 1} + {"b": 2}
+	case op == code.OpAdd && left.Type() == object.HASH_OBJ && right.Type() == object.HASH_OBJ:
+		leftVal := left.(*object.Hash).Pairs
+		rightVal := right.(*object.Hash).Pairs
+		pairs := make(map[object.HashKey]object.HashPair)
+		for k, v := range leftVal {
+			pairs[k] = v
+		}
+		for k, v := range rightVal {
+			pairs[k] = v
+		}
+		return vm.push(&object.Hash{Pairs: pairs})
+
+	// [1] + [2]
+	case op == code.OpAdd && left.Type() == object.ARRAY_OBJ && right.Type() == object.ARRAY_OBJ:
+		leftVal := left.(*object.Array).Elements
+		rightVal := right.(*object.Array).Elements
+		elements := make([]object.Object, len(leftVal)+len(rightVal))
+		elements = append(leftVal, rightVal...)
+		return vm.push(&object.Array{Elements: elements})
+
 	// [1] * 3
-	case left.Type() == object.ARRAY_OBJ && right.Type() == object.INTEGER_OBJ:
+	case op == code.OpMul && left.Type() == object.ARRAY_OBJ && right.Type() == object.INTEGER_OBJ:
 		leftVal := left.(*object.Array).Elements
 		rightVal := int(right.(*object.Integer).Value)
 		elements := leftVal
@@ -537,7 +558,7 @@ func (vm *VM) executeBinaryOperation(op code.Opcode) error {
 		}
 		return vm.push(&object.Array{Elements: elements})
 	// 3 * [1]
-	case left.Type() == object.INTEGER_OBJ && right.Type() == object.ARRAY_OBJ:
+	case op == code.OpMul && left.Type() == object.INTEGER_OBJ && right.Type() == object.ARRAY_OBJ:
 		leftVal := int(left.(*object.Integer).Value)
 		rightVal := right.(*object.Array).Elements
 		elements := rightVal
@@ -547,12 +568,12 @@ func (vm *VM) executeBinaryOperation(op code.Opcode) error {
 		return vm.push(&object.Array{Elements: elements})
 
 	// " " * 4
-	case left.Type() == object.STRING_OBJ && right.Type() == object.INTEGER_OBJ:
+	case op == code.OpMul && left.Type() == object.STRING_OBJ && right.Type() == object.INTEGER_OBJ:
 		leftVal := left.(*object.String).Value
 		rightVal := right.(*object.Integer).Value
 		return vm.push(&object.String{Value: strings.Repeat(leftVal, int(rightVal))})
 	// 4 * " "
-	case left.Type() == object.INTEGER_OBJ && right.Type() == object.STRING_OBJ:
+	case op == code.OpMul && left.Type() == object.INTEGER_OBJ && right.Type() == object.STRING_OBJ:
 		leftVal := left.(*object.Integer).Value
 		rightVal := right.(*object.String).Value
 		return vm.push(&object.String{Value: strings.Repeat(rightVal, int(leftVal))})

vm/vm_test.go

@@ -354,6 +354,16 @@ func TestArrayDuplication(t *testing.T) {
 	runVmTests(t, tests)
 }
 
+func TestArrayMerging(t *testing.T) {
+	tests := []vmTestCase{
+		{"[] + [1]", []int{1}},
+		{"[1] + [2]", []int{1, 2}},
+		{"[1, 2] + [3, 4]", []int{1, 2, 3, 4}},
+	}
+
+	runVmTests(t, tests)
+}
+
 func TestHashLiterals(t *testing.T) {
 	tests := []vmTestCase{
 		{
@@ -378,6 +388,26 @@ func TestHashLiterals(t *testing.T) {
 	runVmTests(t, tests)
 }
 
+func TestHashMerging(t *testing.T) {
+	tests := []vmTestCase{
+		{
+			`{} + {"a": 1}`,
+			map[object.HashKey]int64{
+				(&object.String{Value: "a"}).HashKey(): 1,
+			},
+		},
+		{
+			`{"a": 1} + {"b": 2}`,
+			map[object.HashKey]int64{
+				(&object.String{Value: "a"}).HashKey(): 1,
+				(&object.String{Value: "b"}).HashKey(): 2,
+			},
+		},
+	}
+
+	runVmTests(t, tests)
+}
+
 func TestSelectorExpressions(t *testing.T) {
 	tests := []vmTestCase{
 		{`{"foo": 5}.foo`, 5},
@@ -677,7 +707,7 @@ func TestBuiltinFunctions(t *testing.T) {
 		{
 			`len(1)`,
 			&object.Error{
-				Message: "argument to `len` not supported, got INTEGER",
+				Message: "argument to `len` not supported, got int",
 			},
 		},
 		{`len("one", "two")`,
@@ -692,14 +722,14 @@ func TestBuiltinFunctions(t *testing.T) {
 		{`first([])`, Null},
 		{`first(1)`,
 			&object.Error{
-				Message: "argument to `first` must be ARRAY, got INTEGER",
+				Message: "argument to `first` must be array, got int",
 			},
 		},
 		{`last([1, 2, 3])`, 3},
 		{`last([])`, Null},
 		{`last(1)`,
 			&object.Error{
-				Message: "argument to `last` must be ARRAY, got INTEGER",
+				Message: "argument to `last` must be array, got int",
 			},
 		},
 		{`rest([1, 2, 3])`, []int{2, 3}},
@@ -707,7 +737,7 @@ func TestBuiltinFunctions(t *testing.T) {
 		{`push([], 1)`, []int{1}},
 		{`push(1, 1)`,
 			&object.Error{
-				Message: "argument to `push` must be ARRAY, got INTEGER",
+				Message: "argument to `push` must be array, got int",
 			},
 		},
 		{`input()`, ""},