func (self *Name) Eval(env *scope.Scope) Value {
if val := env.Lookup(self.Identifier); val != nil {
return val.(Value)
} else {
panic(fmt.Sprintf("%s: undefined identifier", self.Identifier))
}
}
func Assign(s *scope.Scope, pattern string, value interface{}) {
if env := s.FindScope(pattern); env != nil {
env.Put(pattern, value)
} else {
panic(fmt.Sprintf("%s was not defined", pattern))
}
}
func BindArguments(env *scope.Scope, params Node, args Value) {
if name, ok := params.(*Name); ok && args == NilPairValue {
// ((lambda x <body>) '())
env.Put(name.Identifier, args)
return
}
for {
if params == NilPair && args == NilPairValue {
return
} else if params == NilPair && args != NilPairValue {
panic(fmt.Sprint("too many arguments"))
} else if params != NilPair && args == NilPairValue {
panic(fmt.Sprint("missing arguments"))
}
switch params.(type) {
case *Pair:
// R5RS declare first element must be a *Name*
name, _ := params.(*Pair).First.(*Name)
pair, ok := args.(*PairValue)
if !ok {
panic(fmt.Sprint("arguments does not match given number"))
}
env.Put(name.Identifier, pair.First)
params = params.(*Pair).Second
args = pair.Second
case *Name:
env.Put(params.(*Name).Identifier, args)
return
}
}
}
func Define(env *scope.Scope, pattern string, value interface{}) {
env.Put(pattern, value)
}