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 // repl loop
  24 if (typeof require !== 'undefined' && require.main === module) {
  25     // Synchronous node.js commandline mode
  26     while (true) {
  27         var line = readline.readline("user> ");
  28         if (line === null) { break; }
  29         try {
  30             if (line) { printer.println(rep(line)); }
  31         } catch (exc) {
  32
  33             if (exc.stack) { printer.println(exc.stack); }
  34             else           { printer.println(exc); }
  35         }
  36     }
  37 }