es6/step0_repl.js

   1 import { readline } from './node_readline'
   2
   3 // read
   4 const READ = str => str
   5
   6 // eval
   7 const EVAL = (ast, env) => ast
   8
   9 // print
  10 const PRINT = exp => exp
  11
  12 // repl
  13 const REP = str => PRINT(EVAL(READ(str), {}))
  14
  15 while (true) {
  16     let line = readline('user> ')
  17     if (line == null) break
  18     if (line) { console.log(REP(line)) }
  19 }