Monkey/object/object.go

package object

import (
	"bytes"
	"fmt"
	"github/runnignwater/monkey/ast"
	"strings"
)

// ObjType type of object
type ObjType string

const (
	IntegerObj     = "INTEGER"
	BooleanObj     = "BOOLEAN"
	NullObj        = "NULL"
	ReturnValueObj = "RETURN_VALUE"
	ErrorObj       = "ERROR"
	FunctionObj    = "FUNCTION"
)

// Object source code as an Object
type Object interface {
	Type() ObjType
	Inspect() string
}

type Integer struct {
	Value int64
}

func (i *Integer) Type() ObjType   { return IntegerObj }
func (i *Integer) Inspect() string { return fmt.Sprintf("%d", i.Value) }

type Boolean struct {
	Value bool
}

func (b *Boolean) Type() ObjType   { return BooleanObj }
func (b *Boolean) Inspect() string { return fmt.Sprintf("%t", b.Value) }

type Null struct{}

func (n *Null) Type() ObjType   { return NullObj }
func (n *Null) Inspect() string { return "null" }

type ReturnValue struct {
	Value Object
}

func (rv *ReturnValue) Type() ObjType   { return ReturnValueObj }
func (rv *ReturnValue) Inspect() string { return rv.Value.Inspect() }

type Error struct {
	Msg string
}

func (e *Error) Type() ObjType   { return ErrorObj }
func (e *Error) Inspect() string { return "ERROR: " + e.Msg }

type Function struct {
	Parameters []*ast.Identifier
	Body       *ast.BlockStatement
	Env        *Environment
}

func (f *Function) Type() ObjType { return FunctionObj }
func (f *Function) Inspect() string {
	var out bytes.Buffer

	params := []string{}
	for _, p := range f.Parameters {
		params = append(params, p.String())
	}

	out.WriteString("fn")
	out.WriteString("(")
	out.WriteString(strings.Join(params, ", "))
	out.WriteString(") {\n")
	out.WriteString(f.Body.String())
	out.WriteString("\n}")

	return out.String()
}