func AddArgs(env *Environment, argNames, args types.Type) (err error) {
var nameP, valueP, name, value types.Type
for nameP, valueP = argNames, args; nameP != nil && valueP != nil; {
name, err = types.Car(nameP)
if err != nil {
return
}
value, err = types.Car(valueP)
if err != nil {
return
}
Define(env, name.(*types.Symbol), value)
nameP, err = types.Cdr(nameP)
valueP, err = types.Cdr(valueP)
}
if nameP != nil || valueP != nil {
return fmt.Errorf("Wrong number of arguments. Expected %s, got %s", argNames, args)
}
return
}
func eq(env interface{}, args t.Type) (t.Type, error) {
first, _ := t.Car(args)
for args, _ := t.Cdr(args); args != nil; args, _ = t.Cdr(args) {
arg, _ := t.Car(args)
if !t.Eq(first, arg) {
return &t.Bool{false}, nil
}
}
return &t.Bool{true}, nil
}
func equal_Number(env interface{}, args t.Type) (t.Type, error) {
arg, _ := t.Car(args)
first, ok := arg.(*t.Number)
if !ok {
return nil, fmt.Errorf("=: Not a number: %s", arg)
}
for args, _ := t.Cdr(args); args != nil; args, _ = t.Cdr(args) {
arg, _ := t.Car(args)
if !t.Eqv(first, arg) {
return &t.Bool{false}, nil
}
}
return &t.Bool{true}, nil
}
func if_s(env *environment.Environment, a types.Type) (types.Type, error) {
test, err := types.Car(a)
if err != nil {
return nil, err
}
b, err := Eval(env, test)
if err != nil {
return nil, err
}
var toEval types.Type
if b.(*types.Bool).Value {
toEval, err = types.Cadr(a)
if err != nil {
return nil, err
}
} else {
temp, err := types.Cdr(a)
if err != nil {
return nil, err
}
toEval, err = types.Cadr(temp)
if err != nil {
return nil, err
}
}
return Eval(env, toEval)
}
func listToArray(env *environment.Environment, list *types.Pair) (argList []types.Type, err error) {
for a := list; a != nil; {
car, err := types.Car(a)
if err != nil {
return nil, err
}
r, err := Eval(env, car)
if err != nil {
return nil, err
}
argList = append(argList, r)
tempA, err := types.Cdr(a)
if err != nil {
return nil, err
}
var ok bool
a, ok = tempA.(*types.Pair)
if !ok && a != nil {
return nil, fmt.Errorf("Eval: arguments not list: %s", tempA)
}
}
return
}
func evalArgs(env *environment.Environment, args types.Type) (types.Type, error) {
if args == nil {
return nil, nil
}
arg, err := types.Car(args)
if err != nil {
return nil, err
}
car, err := Eval(env, arg)
if err != nil {
return nil, err
}
next, err := types.Cdr(args)
if err != nil {
return nil, err
}
cdr, err := evalArgs(env, next)
if err != nil {
return nil, err
}
return types.Cons(car, cdr), nil
}
func sub(env interface{}, args t.Type) (t.Type, error) {
arg, _ := t.Car(args)
n, ok := arg.(*t.Number)
if !ok {
return nil, fmt.Errorf("SUB: Not a number: %s", arg)
}
total := n.Value
for args, _ := t.Cdr(args); args != nil; args, _ = t.Cdr(args) {
arg, _ := t.Car(args)
n, ok := arg.(*t.Number)
if !ok {
return nil, fmt.Errorf("SUB: Not a number: %s", arg)
}
total = total - n.Value
}
return &t.Number{total}, nil
}
func lambda(env *environment.Environment, a types.Type) (types.Type, error) {
args, err := types.Car(a)
if err != nil {
return nil, fmt.Errorf("%s\nLAMBDA: unable to get argument list: %s", err, a)
}
text, err := types.Cdr(a)
if err != nil {
return nil, fmt.Errorf("%s\nLAMBDA: unable to get function body: %s", err, a)
}
return &types.SFunction{text, args, env}, nil
}
func applySpecialForm(env *environment.Environment, name string, args types.Type) (types.Type, error) {
switch name {
case "quote":
return types.Car(args)
case "define":
return nil, define(env, args)
case "lambda":
return lambda(env, args)
case "if":
return if_s(env, args)
}
return nil, nil
}
func add(env interface{}, args t.Type) (t.Type, error) {
var total int64 = 0
for ; args != nil; args, _ = t.Cdr(args) {
arg, _ := t.Car(args)
n, ok := arg.(*t.Number)
if !ok {
return nil, fmt.Errorf("ADD: Not a number: %s", arg)
}
total = total + n.Value
}
return &t.Number{total}, nil
}
func define(env *environment.Environment, args types.Type) error {
name, err := types.Car(args)
if err != nil {
return err
}
value, err := types.Cadr(args)
if err != nil {
return err
}
evaldValue, err := Eval(env, value)
if err != nil {
return err
}
environment.Define(env, name.(*types.Symbol), evaldValue)
return nil
}
func Eval(env *environment.Environment, f types.Type) (types.Type, error) {
if types.IsPair(f) {
car, err := types.Car(f)
if err != nil {
return nil, err
}
cdr, err := types.Cdr(f)
if err != nil {
return nil, err
}
return Apply(env, car, cdr)
}
if types.IsSymbol(f) {
return environment.Get(env, f.(*types.Symbol))
}
return f, nil
}
func begin(env interface{}, args t.Type) (t.Type, error) {
var (
result, expr t.Type
err error
)
for ; args != nil; args, _ = t.Cdr(args) {
expr, err = t.Car(args)
if err != nil {
return nil, err
}
//fmt.Printf("%s\n", expr)
result, err = Eval(env.(*e.Environment), expr)
if err != nil {
return nil, err
}
}
return result, nil
}