jashkenas--coffeescript/lib/rewriter.js

(function() {
  var BALANCED_PAIRS, EXPRESSION_CLOSE, EXPRESSION_END, EXPRESSION_START, IMPLICIT_BLOCK, IMPLICIT_CALL, IMPLICIT_END, IMPLICIT_FUNC, IMPLICIT_UNSPACED_CALL, INVERSES, LINEBREAKS, SINGLE_CLOSERS, SINGLE_LINERS, left, rite, _i, _len, _ref;
  var __indexOf = Array.prototype.indexOf || function(item) {
    for (var i = 0, l = this.length; i < l; i++) {
      if (this[i] === item) return i;
    }
    return -1;
  }, __slice = Array.prototype.slice;
  exports.Rewriter = function() {
    function Rewriter() {}
    Rewriter.prototype.rewrite = function(tokens) {
      this.tokens = tokens;
      this.removeLeadingNewlines();
      this.removeMidExpressionNewlines();
      this.closeOpenCalls();
      this.closeOpenIndexes();
      this.addImplicitIndentation();
      this.tagPostfixConditionals();
      this.addImplicitBraces();
      this.addImplicitParentheses();
      this.ensureBalance(BALANCED_PAIRS);
      this.rewriteClosingParens();
      return this.tokens;
    };
    Rewriter.prototype.scanTokens = function(block) {
      var i, token, tokens;
      tokens = this.tokens;
      i = 0;
      while (token = tokens[i]) {
        i += block.call(this, token, i, tokens);
      }
      return true;
    };
    Rewriter.prototype.detectEnd = function(i, condition, action) {
      var levels, token, tokens, _ref, _ref2;
      tokens = this.tokens;
      levels = 0;
      while (token = tokens[i]) {
        if (levels === 0 && condition.call(this, token, i)) {
          return action.call(this, token, i);
        }
        if (!token || levels < 0) {
          return action.call(this, token, i - 1);
        }
        if (_ref = token[0], __indexOf.call(EXPRESSION_START, _ref) >= 0) {
          levels += 1;
        } else if (_ref2 = token[0], __indexOf.call(EXPRESSION_END, _ref2) >= 0) {
          levels -= 1;
        }
        i += 1;
      }
      return i - 1;
    };
    Rewriter.prototype.removeLeadingNewlines = function() {
      var i, tag, _len, _ref;
      _ref = this.tokens;
      for (i = 0, _len = _ref.length; i < _len; i++) {
        tag = _ref[i][0];
        if (tag !== 'TERMINATOR') {
          break;
        }
      }
      if (i) {
        return this.tokens.splice(0, i);
      }
    };
    Rewriter.prototype.removeMidExpressionNewlines = function() {
      return this.scanTokens(function(token, i, tokens) {
        var _ref;
        if (!(token[0] === 'TERMINATOR' && (_ref = this.tag(i + 1), __indexOf.call(EXPRESSION_CLOSE, _ref) >= 0))) {
          return 1;
        }
        tokens.splice(i, 1);
        return 0;
      });
    };
    Rewriter.prototype.closeOpenCalls = function() {
      var action, condition;
      condition = function(token, i) {
        var _ref;
        return ((_ref = token[0]) === ')' || _ref === 'CALL_END') || token[0] === 'OUTDENT' && this.tag(i - 1) === ')';
      };
      action = function(token, i) {
        return this.tokens[token[0] === 'OUTDENT' ? i - 1 : i][0] = 'CALL_END';
      };
      return this.scanTokens(function(token, i) {
        if (token[0] === 'CALL_START') {
          this.detectEnd(i + 1, condition, action);
        }
        return 1;
      });
    };
    Rewriter.prototype.closeOpenIndexes = function() {
      var action, condition;
      condition = function(token, i) {
        var _ref;
        return (_ref = token[0]) === ']' || _ref === 'INDEX_END';
      };
      action = function(token, i) {
        return token[0] = 'INDEX_END';
      };
      return this.scanTokens(function(token, i) {
        if (token[0] === 'INDEX_START') {
          this.detectEnd(i + 1, condition, action);
        }
        return 1;
      });
    };
    Rewriter.prototype.addImplicitBraces = function() {
      var action, condition, stack, start, startIndent;
      stack = [];
      start = null;
      startIndent = 0;
      condition = function(token, i) {
        var one, tag, three, two, _ref, _ref2;
        _ref = this.tokens.slice(i + 1, i + 3 + 1), one = _ref[0], two = _ref[1], three = _ref[2];
        if ('HERECOMMENT' === (one != null ? one[0] : void 0)) {
          return false;
        }
        tag = token[0];
        return ((tag === 'TERMINATOR' || tag === 'OUTDENT') && !((two != null ? two[0] : void 0) === ':' || (one != null ? one[0] : void 0) === '@' && (three != null ? three[0] : void 0) === ':')) || (tag === ',' && one && ((_ref2 = one[0]) !== 'IDENTIFIER' && _ref2 !== 'NUMBER' && _ref2 !== 'STRING' && _ref2 !== '@' && _ref2 !== 'TERMINATOR' && _ref2 !== 'OUTDENT'));
      };
      action = function(token, i) {
        return this.tokens.splice(i, 0, ['}', '}', token[2]]);
      };
      return this.scanTokens(function(token, i, tokens) {
        var ago, idx, tag, tok, value, _ref, _ref2;
        if (_ref = (tag = token[0]), __indexOf.call(EXPRESSION_START, _ref) >= 0) {
          stack.push([(tag === 'INDENT' && this.tag(i - 1) === '{' ? '{' : tag), i]);
          return 1;
        }
        if (__indexOf.call(EXPRESSION_END, tag) >= 0) {
          start = stack.pop();
          return 1;
        }
        if (!(tag === ':' && ((ago = this.tag(i - 2)) === ':' || ((_ref2 = stack[stack.length - 1]) != null ? _ref2[0] : void 0) !== '{'))) {
          return 1;
        }
        stack.push(['{']);
        idx = ago === '@' ? i - 2 : i - 1;
        if (this.tag(idx - 2) === 'HERECOMMENT') {
          idx -= 2;
        }
        value = new String('{');
        value.generated = true;
        tok = ['{', value, token[2]];
        tok.generated = true;
        tokens.splice(idx, 0, tok);
        this.detectEnd(i + 2, condition, action);
        return 2;
      });
    };
    Rewriter.prototype.addImplicitParentheses = function() {
      var action, noCall;
      noCall = false;
      action = function(token, i) {
        var idx;
        idx = token[0] === 'OUTDENT' ? i + 1 : i;
        return this.tokens.splice(idx, 0, ['CALL_END', ')', token[2]]);
      };
      return this.scanTokens(function(token, i, tokens) {
        var callObject, current, next, prev, seenSingle, tag, _ref, _ref2, _ref3;
        tag = token[0];
        if (tag === 'CLASS' || tag === 'IF' || tag === 'UNLESS') {
          noCall = true;
        }
        _ref = tokens.slice(i - 1, i + 1 + 1), prev = _ref[0], current = _ref[1], next = _ref[2];
        callObject = !noCall && tag === 'INDENT' && next && next.generated && next[0] === '{' && prev && (_ref2 = prev[0], __indexOf.call(IMPLICIT_FUNC, _ref2) >= 0);
        seenSingle = false;
        if (__indexOf.call(LINEBREAKS, tag) >= 0) {
          noCall = false;
        }
        if (prev && !prev.spaced && tag === '?') {
          token.call = true;
        }
        if (!(callObject || (prev != null ? prev.spaced : void 0) && (prev.call || (_ref3 = prev[0], __indexOf.call(IMPLICIT_FUNC, _ref3) >= 0)) && (__indexOf.call(IMPLICIT_CALL, tag) >= 0 || !(token.spaced || token.newLine) && __indexOf.call(IMPLICIT_UNSPACED_CALL, tag) >= 0))) {
          return 1;
        }
        tokens.splice(i, 0, ['CALL_START', '(', token[2]]);
        this.detectEnd(i + (callObject ? 2 : 1), function(token, i) {
          var post, _ref;
          if (!seenSingle && token.fromThen) {
            return true;
          }
          tag = token[0];
          if (tag === 'IF' || tag === 'ELSE' || tag === 'UNLESS' || tag === '->' || tag === '=>') {
            seenSingle = true;
          }
          if ((tag === '.' || tag === '?.' || tag === '::') && this.tag(i - 1) === 'OUTDENT') {
            return true;
          }
          return !token.generated && this.tag(i - 1) !== ',' && __indexOf.call(IMPLICIT_END, tag) >= 0 && (tag !== 'INDENT' || (this.tag(i - 2) !== 'CLASS' && (_ref = this.tag(i - 1), __indexOf.call(IMPLICIT_BLOCK, _ref) < 0) && !((post = this.tokens[i + 1]) && post.generated && post[0] === '{')));
        }, action);
        if (prev[0] === '?') {
          prev[0] = 'FUNC_EXIST';
        }
        return 2;
      });
    };
    Rewriter.prototype.addImplicitIndentation = function() {
      return this.scanTokens(function(token, i, tokens) {
        var action, condition, indent, outdent, starter, tag, _ref, _ref2;
        tag = token[0];
        if (tag === 'TERMINATOR' && this.tag(i + 1) === 'THEN') {
          tokens.splice(i, 1);
          return 0;
        }
        if (tag === 'ELSE' && this.tag(i - 1) !== 'OUTDENT') {
          tokens.splice.apply(tokens, [i, 0].concat(__slice.call(this.indentation(token))));
          return 2;
        }
        if (tag === 'CATCH' && ((_ref = this.tag(i + 2)) === 'OUTDENT' || _ref === 'TERMINATOR' || _ref === 'FINALLY')) {
          tokens.splice.apply(tokens, [i + 2, 0].concat(__slice.call(this.indentation(token))));
          return 4;
        }
        if (__indexOf.call(SINGLE_LINERS, tag) >= 0 && this.tag(i + 1) !== 'INDENT' && !(tag === 'ELSE' && this.tag(i + 1) === 'IF')) {
          starter = tag;
          _ref2 = this.indentation(token), indent = _ref2[0], outdent = _ref2[1];
          if (starter === 'THEN') {
            indent.fromThen = true;
          }
          indent.generated = outdent.generated = true;
          tokens.splice(i + 1, 0, indent);
          condition = function(token, i) {
            var _ref;
            return token[1] !== ';' && (_ref = token[0], __indexOf.call(SINGLE_CLOSERS, _ref) >= 0) && !(token[0] === 'ELSE' && (starter !== 'IF' && starter !== 'THEN'));
          };
          action = function(token, i) {
            return this.tokens.splice((this.tag(i - 1) === ',' ? i - 1 : i), 0, outdent);
          };
          this.detectEnd(i + 2, condition, action);
          if (tag === 'THEN') {
            tokens.splice(i, 1);
          }
          return 1;
        }
        return 1;
      });
    };
    Rewriter.prototype.tagPostfixConditionals = function() {
      var condition;
      condition = function(token, i) {
        var _ref;
        return (_ref = token[0]) === 'TERMINATOR' || _ref === 'INDENT';
      };
      return this.scanTokens(function(token, i) {
        var original, _ref;
        if ((_ref = token[0]) !== 'IF' && _ref !== 'UNLESS') {
          return 1;
        }
        original = token;
        this.detectEnd(i + 1, condition, function(token, i) {
          if (token[0] !== 'INDENT') {
            return original[0] = 'POST_' + original[0];
          }
        });
        return 1;
      });
    };
    Rewriter.prototype.ensureBalance = function(pairs) {
      var close, level, levels, open, openLine, tag, token, _i, _j, _len, _len2, _ref, _ref2;
      levels = {};
      openLine = {};
      _ref = this.tokens;
      for (_i = 0, _len = _ref.length; _i < _len; _i++) {
        token = _ref[_i];
        tag = token[0];
        for (_j = 0, _len2 = pairs.length; _j < _len2; _j++) {
          _ref2 = pairs[_j], open = _ref2[0], close = _ref2[1];
          levels[open] |= 0;
          if (tag === open) {
            if (levels[open]++ === 0) {
              openLine[open] = token[2];
            }
          } else if (tag === close && --levels[open] < 0) {
            throw Error("too many " + token[1] + " on line " + (token[2] + 1));
          }
        }
      }
      for (open in levels) {
        level = levels[open];
        if (level > 0) {
          throw Error("unclosed " + open + " on line " + (openLine[open] + 1));
        }
      }
      return this;
    };
    Rewriter.prototype.rewriteClosingParens = function() {
      var debt, key, stack;
      stack = [];
      debt = {};
      for (key in INVERSES) {
        debt[key] = 0;
      }
      return this.scanTokens(function(token, i, tokens) {
        var inv, match, mtag, oppos, tag, val, _ref;
        if (_ref = (tag = token[0]), __indexOf.call(EXPRESSION_START, _ref) >= 0) {
          stack.push(token);
          return 1;
        }
        if (__indexOf.call(EXPRESSION_END, tag) < 0) {
          return 1;
        }
        if (debt[inv = INVERSES[tag]] > 0) {
          debt[inv] -= 1;
          tokens.splice(i, 1);
          return 0;
        }
        match = stack.pop();
        mtag = match[0];
        oppos = INVERSES[mtag];
        if (tag === oppos) {
          return 1;
        }
        debt[mtag] += 1;
        val = [oppos, mtag === 'INDENT' ? match[1] : oppos];
        if (this.tag(i + 2) === mtag) {
          tokens.splice(i + 3, 0, val);
          stack.push(match);
        } else {
          tokens.splice(i, 0, val);
        }
        return 1;
      });
    };
    Rewriter.prototype.indentation = function(token) {
      return [['INDENT', 2, token[2]], ['OUTDENT', 2, token[2]]];
    };
    Rewriter.prototype.tag = function(i) {
      var _ref;
      return (_ref = this.tokens[i]) != null ? _ref[0] : void 0;
    };
    return Rewriter;
  }();
  BALANCED_PAIRS = [['(', ')'], ['[', ']'], ['{', '}'], ['INDENT', 'OUTDENT'], ['CALL_START', 'CALL_END'], ['PARAM_START', 'PARAM_END'], ['INDEX_START', 'INDEX_END']];
  INVERSES = {};
  EXPRESSION_START = [];
  EXPRESSION_END = [];
  for (_i = 0, _len = BALANCED_PAIRS.length; _i < _len; _i++) {
    _ref = BALANCED_PAIRS[_i], left = _ref[0], rite = _ref[1];
    EXPRESSION_START.push(INVERSES[rite] = left);
    EXPRESSION_END.push(INVERSES[left] = rite);
  }
  EXPRESSION_CLOSE = ['CATCH', 'WHEN', 'ELSE', 'FINALLY'].concat(EXPRESSION_END);
  IMPLICIT_FUNC = ['IDENTIFIER', 'SUPER', ')', 'CALL_END', ']', 'INDEX_END', '@', 'THIS'];
  IMPLICIT_CALL = ['IDENTIFIER', 'NUMBER', 'STRING', 'JS', 'REGEX', 'NEW', 'PARAM_START', 'CLASS', 'IF', 'UNLESS', 'TRY', 'SWITCH', 'THIS', 'BOOL', 'UNARY', '@', '->', '=>', '[', '(', '{', '--', '++'];
  IMPLICIT_UNSPACED_CALL = ['+', '-'];
  IMPLICIT_BLOCK = ['->', '=>', '{', '[', ','];
  IMPLICIT_END = ['POST_IF', 'POST_UNLESS', 'FOR', 'WHILE', 'UNTIL', 'WHEN', 'BY', 'LOOP', 'TERMINATOR', 'INDENT'];
  SINGLE_LINERS = ['ELSE', '->', '=>', 'TRY', 'FINALLY', 'THEN'];
  SINGLE_CLOSERS = ['TERMINATOR', 'CATCH', 'FINALLY', 'ELSE', 'OUTDENT', 'LEADING_WHEN'];
  LINEBREAKS = ['TERMINATOR', 'INDENT', 'OUTDENT'];
}).call(this);