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env.go
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/
env.go
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package internal
type env struct {
enclosing *env
values map[string]interface{}
}
func newEnv(enclosing *env) *env {
return &env{
enclosing: enclosing,
values: make(map[string]interface{}),
}
}
func (e *env) get(state *interpreterState, name *token) interface{} {
if value, ok := e.values[name.lexeme]; ok {
return value
}
if e.enclosing != nil {
return e.enclosing.get(state, name)
}
state.runtimeErr(errUndefinedVar, name)
return nil
}
func (e *env) define(name string, value interface{}) {
e.values[name] = value
}
func (e *env) assign(state *interpreterState, name *token, value interface{}) {
if _, ok := e.values[name.lexeme]; ok {
e.values[name.lexeme] = value
return
}
if e.enclosing != nil {
e.enclosing.assign(state, name, value)
return
}
state.runtimeErr(errUndefinedVar, name)
}