import type { Value } from "./value"

export class Scope {
  locals = new Map<string, Value>()
  parent?: Scope

  constructor(parent?: Scope) {
    this.parent = parent
  }

  get(name: string): Value | undefined {
    if (this.locals.has(name))
      return this.locals.get(name)!

    if (this.parent)
      return this.parent.get(name)

    return undefined
  }

  set(name: string, value: Value) {
    if (this.locals.has(name))
      this.locals.set(name, value)
    else if (this.parent?.has(name))
      this.parent.set(name, value)
    else
      this.locals.set(name, value)
  }

  has(name: string): boolean {
    return this.locals.has(name) || this.parent?.has(name) || false
  }
}