implemented backslash for continuation comments

compiler/lexer.nim

@@ -172,7 +172,7 @@ proc tokToStr*(tok: TToken): string =
   of tkParLe..tkColon, tkEof, tkInd, tkSad, tkDed, tkAccent: 
     result = tokTypeToStr[tok.tokType]
   else: 
-    if (tok.ident != nil): 
+    if tok.ident != nil:
       result = tok.ident.s
     else: 
       InternalError("tokToStr")
@@ -654,19 +654,29 @@ proc scanComment(L: var TLexer, tok: var TToken) =
   # column after only whitespace
   tok.tokType = tkComment
   var col = getColNumber(L, pos)
-  while true: 
-    while not (buf[pos] in {CR, LF, lexbase.EndOfFile}): 
+  while true:
+    var lastBackslash = -1
+    while buf[pos] notin {CR, LF, lexbase.EndOfFile}:
+      if buf[pos] == '\\': lastBackslash = pos+1
       add(tok.literal, buf[pos])
       inc(pos)
+    if lastBackslash > 0:
+      # a backslash is a continuation character if only followed by spaces
+      # plus a newline:
+      while buf[lastBackslash] == ' ': inc(lastBackslash)
+      if buf[lastBackslash] notin {CR, LF, lexbase.EndOfFile}:
+        # false positive:
+        lastBackslash = -1
+
     pos = handleCRLF(L, pos)
     buf = L.buf
     var indent = 0
     while buf[pos] == ' ': 
       inc(pos)
       inc(indent)
-    if (buf[pos] == '#') and (col == indent): 
-      tok.literal = tok.literal & "\n"
-    else: 
+    if buf[pos] == '#' and (col == indent or lastBackslash > 0):
+      tok.literal.add "\n"
+    else:
       if buf[pos] > ' ': 
         L.indentAhead = indent
         inc(L.dedent)

doc/manual.txt

@@ -135,6 +135,16 @@ aligned to the preceding one, it does not start a new comment:
   # statement.
   i = i + 1 # This a new comment that is NOT
   echo(i)   # continued here, because this comment refers to the echo statement
+
+
+The alignment requirement does not hold if the preceding comment piece ends in
+a backslash (followed by optional whitespace): 
+
+.. code-block:: nimrod
+  type
+    TMyObject {.final, pure, acyclic.} = object  # comment continues: \
+      # we have lots of space here to comment 'TMyObject'.
+      # This line belongs to the comment as it's properly aligned.
 
 Comments are tokens; they are only allowed at certain places in the input file
 as they belong to the syntax tree! This feature enables perfect source-to-source

doc/tut1.txt

@@ -130,6 +130,17 @@ comments need to be aligned at the same column:
   i = i + 1 # This a new comment that is NOT
   echo(i)   # continued here, because this comment refers to the echo statement
 
+
+The alignment requirement does not hold if the preceding comment piece ends in
+a backslash:
+
+.. code-block:: nimrod
+  type
+    TMyObject {.final, pure, acyclic.} = object  # comment continues: \
+      # we have lots of space here to comment 'TMyObject'.
+      # This line belongs to the comment as it's properly aligned.
+
+
 Comments are tokens; they are only allowed at certain places in the input file
 as they belong to the syntax tree! This feature enables perfect source-to-source
 transformations (such as pretty-printing) and simpler documentation generators.

packages/docutils/rst.nim

@@ -648,8 +648,8 @@ proc parseBackslash(p: var TRstParser, father: PRstNode) =
     # XXX: Unicode?
     inc(p.idx)
     if p.tok[p.idx].kind != tkWhite: add(father, newLeaf(p))
-    inc(p.idx)
-  else: 
+    if p.tok[p.idx].kind != tkEof: inc(p.idx)
+  else:
     add(father, newLeaf(p))
     inc(p.idx)
 

todo.txt

@@ -3,7 +3,6 @@ version 0.9.0
 
 - make 'bind' default for templates and introduce 'mixin'
 - implement 'bind' for macros
-- use ``\`` for comment continuations
 - ``final`` should be the default for objects
 - implement "closure tuple consists of a single 'ref'" optimization
 - implement for loop transformation for first class iterators

web/news.txt

@@ -51,7 +51,7 @@ Library Additions
 - Added ``system.clamp`` to limit a value within an interval ``[a, b]``.
 - Added ``strutils.continuesWith``.
 - Added ``system.getStackTrace``.
-- Added ``system.||`` for parallel for loop support.
+- Added ``system.||`` for parallel ``for`` loop support.
 - The GC supports (soft) realtime systems via ``GC_setMaxPause`` 
   and ``GC_step`` procs.
 - The sockets module now supports ssl through the OpenSSL library, ``recvLine``
@@ -106,6 +106,8 @@ Changes affecting backwards compatibility
   Activate the warning ``ImplicitClosure`` to make the compiler list the 
   occurances of proc types which are affected.
 - The Nimrod type system now distinguishes ``openarray`` from ``varargs``.
+- Templates are now ``hygienic``. Use the ``dirty`` pragma to get the old
+  behaviour.
 
 
 Compiler Additions
@@ -151,6 +153,10 @@ Language Additions
   line: ``inc i; inc j``.
 - ``bind`` supports overloaded symbols and operators.
 - A ``distinct`` type can now borrow from generic procs.
+- Added the pragmas ``gensym``, ``inject`` and ``dirty`` for hygiene
+  in templates.
+- Comments can be continued with a backslash continuation character so that
+  comment pieces don't have to align on the same column.
 
 
 2012-02-09 Version 0.8.14 released