js/step1_read_print.js

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