anchor.diff:  
     /// A counter for spaces that should be emitted preceding the next token.
     int leadingSpaces = 0;
  -
  -  /// A flag to specify whether line-leading spaces should be preserved (and
  -  /// addded to the indent level).
  -  bool allowLineLeadingSpaces;
   
     /// A flag to specify whether zero-length spaces should be emmitted.
     bool emitEmptySpaces = false;
  
positive.code: 
    emitSpaces() {
      if (leadingSpaces > 0 || emitEmptySpaces) {
        if (allowLineLeadingSpaces || !writer.currentLine.isWhitespace()) {
          writer.spaces(leadingSpaces, breakWeight: currentBreakWeight);
        }
        leadingSpaces = 0;
        allowLineLeadingSpaces = false;
        emitEmptySpaces = false;
        currentBreakWeight = DEFAULT_SPACE_WEIGHT;
      }
  
negative.code:     space(breakWeight: UNBREAKABLE_SPACE_WEIGHT);
    }
  
    /// Emit [n] spaces.
    space({n: 1, breakWeight: DEFAULT_SPACE_WEIGHT}) {
      // TODO(pquitslund): replace with a proper space token.
      leadingSpaces += n;
      currentBreakWeight = breakWeight;
    }
  
  