const AST = require('./ast')
const core = require('./core')
const OsloError = require('./osloError')

module.exports = class Env {
  constructor(parent = null) {
    this.data = {}

    if (parent) {
      Object.keys(parent.data).forEach(key => {
        this.data[key] = parent.data[key]
      })
    } else {
      Object.keys(core).forEach(key => {
        this.data[key] = core[key]
      })
    }
  }

  get(symbol) {
    if (this.data[symbol.name]) {
      return this.data[symbol.name]
    }

    return new OsloError({
      line: symbol.line,
      message: `Symbol '${symbol.name}' is not bound`,
    })
  }

  set(symbol, value) {
    this.data[symbol.name] = value
  }
}