jashkenas--coffeescript/lib/coffee_script/rewriter.js

(function(){
  var BALANCED_PAIRS, EXPRESSION_CLOSE, EXPRESSION_START, EXPRESSION_TAIL, IMPLICIT_CALL, IMPLICIT_END, IMPLICIT_FUNC, INVERSES, SINGLE_CLOSERS, SINGLE_LINERS, __a, __b, __c, __d, __e, __f, __g, __h, pair, re;
  // In order to keep the grammar simple, the stream of tokens that the Lexer
  // emits is rewritten by the Rewriter, smoothing out ambiguities, mis-nested
  // indentation, and single-line flavors of expressions.
  exports.Rewriter = (re = function re() {  });
  // Tokens that must be balanced.
  BALANCED_PAIRS = [['(', ')'], ['[', ']'], ['{', '}'], ['INDENT', 'OUTDENT'], ['PARAM_START', 'PARAM_END'], ['CALL_START', 'CALL_END'], ['INDEX_START', 'INDEX_END']];
  // Tokens that signal the start of a balanced pair.
  EXPRESSION_START = (function() {
    __a = []; __b = BALANCED_PAIRS;
    for (__c = 0; __c < __b.length; __c++) {
      pair = __b[__c];
      __a.push(pair[0]);
    }
    return __a;
  }).call(this);
  // Tokens that signal the end of a balanced pair.
  EXPRESSION_TAIL = (function() {
    __d = []; __e = BALANCED_PAIRS;
    for (__f = 0; __f < __e.length; __f++) {
      pair = __e[__f];
      __d.push(pair[1]);
    }
    return __d;
  }).call(this);
  // Tokens that indicate the close of a clause of an expression.
  EXPRESSION_CLOSE = ['CATCH', 'WHEN', 'ELSE', 'FINALLY'].concat(EXPRESSION_TAIL);
  // Tokens pairs that, in immediate succession, indicate an implicit call.
  IMPLICIT_FUNC = ['IDENTIFIER', 'SUPER', ')', 'CALL_END', ']', 'INDEX_END'];
  IMPLICIT_END = ['IF', 'UNLESS', 'FOR', 'WHILE', "\n", 'OUTDENT'];
  IMPLICIT_CALL = ['IDENTIFIER', 'NUMBER', 'STRING', 'JS', 'REGEX', 'NEW', 'PARAM_START', 'TRY', 'DELETE', 'TYPEOF', 'SWITCH', 'ARGUMENTS', 'TRUE', 'FALSE', 'YES', 'NO', 'ON', 'OFF', '!', '!!', 'NOT', '->', '=>', '[', '(', '{'];
  // The inverse mappings of token pairs we're trying to fix up.
  INVERSES = {
  };
  __g = BALANCED_PAIRS;
  for (__h = 0; __h < __g.length; __h++) {
    pair = __g[__h];
    INVERSES[pair[0]] = pair[1];
    INVERSES[pair[1]] = pair[0];
  }
  // Single-line flavors of block expressions that have unclosed endings.
  // The grammar can't disambiguate them, so we insert the implicit indentation.
  SINGLE_LINERS = ['ELSE', "->", "=>", 'TRY', 'FINALLY', 'THEN'];
  SINGLE_CLOSERS = ["\n", 'CATCH', 'FINALLY', 'ELSE', 'OUTDENT', 'LEADING_WHEN', 'PARAM_START'];
  // Rewrite the token stream in multiple passes, one logical filter at
  // a time. This could certainly be changed into a single pass through the
  // stream, with a big ol' efficient switch, but it's much nicer like this.
  re.prototype.rewrite = function rewrite(tokens) {
    this.tokens = tokens;
    this.adjust_comments();
    // this.remove_leading_newlines()
    // this.remove_mid_expression_newlines()
    // this.move_commas_outside_outdents()
    // this.close_open_calls_and_indexes()
    // this.add_implicit_parentheses()
    // this.add_implicit_indentation()
    // this.ensure_balance(BALANCED_PAIRS)
    // this.rewrite_closing_parens()
    return this.tokens;
  };
  // Rewrite the token stream, looking one token ahead and behind.
  // Allow the return value of the block to tell us how many tokens to move
  // forwards (or backwards) in the stream, to make sure we don't miss anything
  // as the stream changes length under our feet.
  re.prototype.scan_tokens = function scan_tokens(yield) {
    var i, move;
    i = 0;
    while (true) {
      if (!(this.tokens[i])) {
        break;
      }
      move = yield(this.tokens[i - 1], this.tokens[i], this.tokens[i + 1], i);
      i += move;
    }
    return true;
  };
  // Massage newlines and indentations so that comments don't have to be
  // correctly indented, or appear on their own line.
  re.prototype.adjust_comments = function adjust_comments() {
    return this.scan_tokens(function(prev, token, post, i) {
      var after, before;
      if (!(token[0] === 'COMMENT')) {
        return 1;
      }
      before = this.tokens[i - 2];
      after = this.tokens[i + 2];
      if (before && after && ((before[0] === 'INDENT' && after[0] === 'OUTDENT') || (before[0] === 'OUTDENT' && after[0] === 'INDENT')) && before[1] === after[1]) {
        this.tokens.splice(i + 2, 1);
        this.tokens.splice(i - 2, 1);
        return 0;
      } else if (prev[0] === "\n" && after[0] === 'INDENT') {
        this.tokens.splice(i + 2, 1);
        this.tokens[i - 1] = after;
        return 1;
      } else if (prev[0] !== "\n" && prev[0] !== 'INDENT' && prev[0] !== 'OUTDENT') {
        this.tokens.splice(i, 0, ["\n", "\n"]);
        return 2;
      } else {
        return 1;
      }
    });
  };
})();