js/step0_repl.js

   1 if (typeof module !== 'undefined') {
   2     var readline = require('./node_readline');
   3 }
   4
   5 // read
   6 function READ(str) {
   7     return str;
   8 }
   9
  10 // eval
  11 function EVAL(ast, env) {
  12     return eval(ast);
  13 }
  14
  15 // print
  16 function PRINT(exp) {
  17     return exp;
  18 }
  19
  20 // repl
  21 var rep = function(str) { return PRINT(EVAL(READ(str), {})); };
  22
  23 if (typeof require === 'undefined') {
  24     // Asynchronous browser mode
  25     readline.rlwrap(function(line) { return rep(line); },
  26                     function(exc) {
  27                         if (exc.stack) { console.log(exc.stack); } else { console.log(exc); }
  28                     });
  29 } else if (require.main === module) {
  30     // Synchronous node.js commandline mode
  31     while (true) {
  32         var line = readline.readline("user> ");
  33         if (line === null) { break; }
  34         try {
  35             if (line) { console.log(rep(line)); }
  36         } catch (exc) {
  37             if (exc.stack) { console.log(exc.stack); } else { console.log(exc); }
  38         }
  39     }
  40 } else {
  41     exports.rep = rep;
  42 }