Fix offset calculation for parsed nodes.

Closes #335.

This builds on #117 by ensuring that not only are line & column
information corrected to account for control characters inserted by the
preprocessor, but offset information is too. Unfortunately this expands
the hack that overrides the code generated by PEGjs, but it seemed the
cleanest and most performant way to solve the problem.

src/grammar.pegcoffee

@@ -259,7 +259,19 @@
  r = p = rp = id
 
  `
- // XXX: this overrides the function with the same name generated by PEGjs; see comment within
+ // XXX: The functions below override the default code generated by PEGjs.
+ // CoffeeScriptRedux has a preprocessor that adds control characters to
+ // mark indents/outdents/etc for PEGjs. These characters cause the line,
+ // column, and offset values to differ from the original input source code,
+ // so this section exists to properly hide those control characters when
+ // reporting location information. See #117 & #335.
+
+ var csr$controlCharacterCount = 0;
+
+ function offset() {
+ return peg$reportedPos - csr$controlCharacterCount;
+ }
+
  function peg$computePosDetails() {
  function advanceCachedReportedPos() {
  var ch;
@@ -274,16 +286,18 @@
  peg$cachedPosDetails.line++;
  peg$cachedPosDetails.column = 1;
  peg$cachedPosDetails.seenCR = true;
- // XXX: strip control characters when calculating position information; see #117
  } else if(!/[\uEFEF\uEFFE\uEFFF]/.test(ch)) {
  peg$cachedPosDetails.column++;
  peg$cachedPosDetails.seenCR = false;
+ } else {
+ csr$controlCharacterCount++;
  }
  }
  }
 
  if (peg$cachedPos !== peg$reportedPos) {
  if (peg$cachedPos > peg$reportedPos) {
+ csr$controlCharacterCount = 0;
  peg$cachedPos = 0;
  peg$cachedPosDetails = { line: 1, column: 1, seenCR: false };
  }

test/parser.coffee

@@ -3,6 +3,15 @@ suite 'Parser', ->
  setup ->
  @shouldParse = (input) -> doesNotThrow -> parse input
  @shouldNotParse = (input) -> throws -> parse input
+ @checkNodeRaw = (node, source) =>
+ rawAtOffset = source[node.offset...(node.offset + node.raw.length)]
+ if node.raw isnt rawAtOffset
+ fail "expected #{node.className} raw to equal #{JSON.stringify(rawAtOffset)}, but was #{JSON.stringify(node.raw)}"
+ for own prop, child of node
+ if Array.isArray child
+ @checkNodeRaw element, source for element in child
+ else if child instanceof CoffeeScript.Nodes.Nodes
+ @checkNodeRaw child, source
 
 
  test 'empty program', -> @shouldParse ''
@@ -172,9 +181,9 @@ suite 'Parser', ->
  suite 'position/offset preservation', ->
 
  test 'basic indentation', ->
- ast = parse '''
+ source = '''
  fn = ->
  body
- ''', raw: yes
- eq 3, ast.body.statements[0].expression.body.statements[0].column
- eq 11, ast.body.statements[0].expression.body.statements[0].offset
+ '''
+ ast = parse source, raw: yes
+ @checkNodeRaw ast, source