// This is a set manipulation.
func (self *Define) Eval(env *scope.Scope) value.Value {
fmt.Println("Define#Eval")
var_ := self.var_.(*Ident)
val := self.expr.Eval(env)
env.Insert(var_.Name, scope.NewObj(val))
// Define does not have return val.
return nil
}
func (self *Letrec) Eval(env *scope.Scope) value.Value {
local := scope.NewScope(env)
nbind := len(self.bindings.Bindings)
for i := 0; i < nbind; i++ {
bind := self.bindings.Bindings[i]
local.Insert(bind.var_, scope.NewObj(bind.init.Eval(local)))
}
for i := nbind - 1; i >= 0; i-- {
bind := self.bindings.Bindings[i]
local.Insert(bind.var_, scope.NewObj(bind.init.Eval(local)))
}
var ret value.Value
for _, node := range self.body {
ret = node.Eval(local)
}
return ret
}
// This is a set manipulation.
func (self *Set) Eval(env *scope.Scope) value.Value {
fmt.Println("Set#Eval")
var_ := self.var_.(*Ident)
val := self.expr.Eval(env)
if obj := env.Lookup(var_.Name, true); obj == nil {
panic("set!: assignment disallowed.")
}
env.Insert(var_.Name, scope.NewObj(val))
// Define does not have return val.
return nil
}
func (self *LetStar) Eval(env *scope.Scope) value.Value {
fmt.Println("#LetStar#Eval")
local := scope.NewScope(env)
for _, bind := range self.bindings.Bindings {
local.Insert(bind.var_, scope.NewObj(bind.init.Eval(local)))
}
var ret value.Value
for _, node := range self.body {
ret = node.Eval(local)
}
return ret
}
func precedureCall(closure *value.Closure, args ...value.Value) value.Value {
t := closure.Lambda.(*Lambda)
env := closure.Env.(*scope.Scope)
formals := t.Formals.(*Tuple)
body := t.Body.(Node)
nargs := len(formals.Nodes)
if nargs != len(args) {
panic(fmt.Errorf(
`the expected number of arguments does not match the given number
expected: %v
given: %v`, len(formals.Nodes), nargs))
}
for i := 0; i < nargs; i++ {
env.Insert(formals.Nodes[i].(*Ident).Name, scope.NewObj(args[i]))
}
return body.Eval(env)
}