Initial revision
diff --git a/Lib/idlelib/AutoIndent.py b/Lib/idlelib/AutoIndent.py
new file mode 100644
index 0000000..6d38481
--- /dev/null
+++ b/Lib/idlelib/AutoIndent.py
@@ -0,0 +1,554 @@
+import string
+#from Tkinter import TclError
+#import tkMessageBox
+#import tkSimpleDialog
+
+###$ event <<newline-and-indent>>
+###$ win <Key-Return>
+###$ win <KP_Enter>
+###$ unix <Key-Return>
+###$ unix <KP_Enter>
+
+###$ event <<indent-region>>
+###$ win <Control-bracketright>
+###$ unix <Alt-bracketright>
+###$ unix <Control-bracketright>
+
+###$ event <<dedent-region>>
+###$ win <Control-bracketleft>
+###$ unix <Alt-bracketleft>
+###$ unix <Control-bracketleft>
+
+###$ event <<comment-region>>
+###$ win <Alt-Key-3>
+###$ unix <Alt-Key-3>
+
+###$ event <<uncomment-region>>
+###$ win <Alt-Key-4>
+###$ unix <Alt-Key-4>
+
+###$ event <<tabify-region>>
+###$ win <Alt-Key-5>
+###$ unix <Alt-Key-5>
+
+###$ event <<untabify-region>>
+###$ win <Alt-Key-6>
+###$ unix <Alt-Key-6>
+
+import PyParse
+
+class AutoIndent:
+
+    menudefs = [
+        ('format', [       # /s/edit/format   dscherer@cmu.edu
+            None,
+            ('_Indent region', '<<indent-region>>'),
+            ('_Dedent region', '<<dedent-region>>'),
+            ('Comment _out region', '<<comment-region>>'),
+            ('U_ncomment region', '<<uncomment-region>>'),
+            ('Tabify region', '<<tabify-region>>'),
+            ('Untabify region', '<<untabify-region>>'),
+            ('Toggle tabs', '<<toggle-tabs>>'),
+            ('New indent width', '<<change-indentwidth>>'),
+        ]),
+    ]
+
+    keydefs = {
+        '<<smart-backspace>>': ['<Key-BackSpace>'],
+        '<<newline-and-indent>>': ['<Key-Return>', '<KP_Enter>'],
+        '<<smart-indent>>': ['<Key-Tab>']
+    }
+
+    windows_keydefs = {
+        '<<indent-region>>': ['<Control-bracketright>'],
+        '<<dedent-region>>': ['<Shift-Tab>',     # dscherer@cmu.edu
+                              '<Control-bracketleft>'],
+        '<<comment-region>>': ['<Alt-Key-3>'],
+        '<<uncomment-region>>': ['<Alt-Key-4>'],
+        '<<tabify-region>>': ['<Alt-Key-5>'],
+        '<<untabify-region>>': ['<Alt-Key-6>'],
+        '<<toggle-tabs>>': ['<Alt-Key-t>'],
+        '<<change-indentwidth>>': ['<Alt-Key-u>'],
+    }
+
+    unix_keydefs = {
+        '<<indent-region>>': ['<Alt-bracketright>',
+                              '<Meta-bracketright>',
+                              '<Control-bracketright>'],
+        '<<dedent-region>>': ['<Alt-bracketleft>',
+                              '<Meta-bracketleft>',
+                              '<Control-bracketleft>'],
+        '<<comment-region>>': ['<Alt-Key-3>', '<Meta-Key-3>'],
+        '<<uncomment-region>>': ['<Alt-Key-4>', '<Meta-Key-4>'],
+        '<<tabify-region>>': ['<Alt-Key-5>', '<Meta-Key-5>'],
+        '<<untabify-region>>': ['<Alt-Key-6>', '<Meta-Key-6>'],
+        '<<toggle-tabs>>': ['<Alt-Key-t>'],
+        '<<change-indentwidth>>': ['<Alt-Key-u>'],
+    }
+
+    # usetabs true  -> literal tab characters are used by indent and
+    #                  dedent cmds, possibly mixed with spaces if
+    #                  indentwidth is not a multiple of tabwidth
+    #         false -> tab characters are converted to spaces by indent
+    #                  and dedent cmds, and ditto TAB keystrokes
+    # indentwidth is the number of characters per logical indent level.
+    # tabwidth is the display width of a literal tab character.
+    # CAUTION:  telling Tk to use anything other than its default
+    # tab setting causes it to use an entirely different tabbing algorithm,
+    # treating tab stops as fixed distances from the left margin.
+    # Nobody expects this, so for now tabwidth should never be changed.
+    usetabs = 1
+    indentwidth = 4
+    tabwidth = 8    # for IDLE use, must remain 8 until Tk is fixed
+
+    # If context_use_ps1 is true, parsing searches back for a ps1 line;
+    # else searches for a popular (if, def, ...) Python stmt.
+    context_use_ps1 = 0
+
+    # When searching backwards for a reliable place to begin parsing,
+    # first start num_context_lines[0] lines back, then
+    # num_context_lines[1] lines back if that didn't work, and so on.
+    # The last value should be huge (larger than the # of lines in a
+    # conceivable file).
+    # Making the initial values larger slows things down more often.
+    num_context_lines = 50, 500, 5000000
+
+    def __init__(self, editwin):
+        self.editwin = editwin
+        self.text = editwin.text
+
+    def config(self, **options):
+        for key, value in options.items():
+            if key == 'usetabs':
+                self.usetabs = value
+            elif key == 'indentwidth':
+                self.indentwidth = value
+            elif key == 'tabwidth':
+                self.tabwidth = value
+            elif key == 'context_use_ps1':
+                self.context_use_ps1 = value
+            else:
+                raise KeyError, "bad option name: %s" % `key`
+
+    # If ispythonsource and guess are true, guess a good value for
+    # indentwidth based on file content (if possible), and if
+    # indentwidth != tabwidth set usetabs false.
+    # In any case, adjust the Text widget's view of what a tab
+    # character means.
+
+    def set_indentation_params(self, ispythonsource, guess=1):
+        if guess and ispythonsource:
+            i = self.guess_indent()
+            if 2 <= i <= 8:
+                self.indentwidth = i
+            if self.indentwidth != self.tabwidth:
+                self.usetabs = 0
+
+        self.editwin.set_tabwidth(self.tabwidth)
+
+    def smart_backspace_event(self, event):
+        text = self.text
+        first, last = self.editwin.get_selection_indices()
+        if first and last:
+            text.delete(first, last)
+            text.mark_set("insert", first)
+            return "break"
+        # Delete whitespace left, until hitting a real char or closest
+        # preceding virtual tab stop.
+        chars = text.get("insert linestart", "insert")
+        if chars == '':
+            if text.compare("insert", ">", "1.0"):
+                # easy: delete preceding newline
+                text.delete("insert-1c")
+            else:
+                text.bell()     # at start of buffer
+            return "break"
+        if  chars[-1] not in " \t":
+            # easy: delete preceding real char
+            text.delete("insert-1c")
+            return "break"
+        # Ick.  It may require *inserting* spaces if we back up over a
+        # tab character!  This is written to be clear, not fast.
+        expand, tabwidth = string.expandtabs, self.tabwidth
+        have = len(expand(chars, tabwidth))
+        assert have > 0
+        want = int((have - 1) / self.indentwidth) * self.indentwidth
+        ncharsdeleted = 0
+        while 1:
+            chars = chars[:-1]
+            ncharsdeleted = ncharsdeleted + 1
+            have = len(expand(chars, tabwidth))
+            if have <= want or chars[-1] not in " \t":
+                break
+        text.undo_block_start()
+        text.delete("insert-%dc" % ncharsdeleted, "insert")
+        if have < want:
+            text.insert("insert", ' ' * (want - have))
+        text.undo_block_stop()
+        return "break"
+
+    def smart_indent_event(self, event):
+        # if intraline selection:
+        #     delete it
+        # elif multiline selection:
+        #     do indent-region & return
+        # indent one level
+        text = self.text
+        first, last = self.editwin.get_selection_indices()
+        text.undo_block_start()
+        try:
+            if first and last:
+                if index2line(first) != index2line(last):
+                    return self.indent_region_event(event)
+                text.delete(first, last)
+                text.mark_set("insert", first)
+            prefix = text.get("insert linestart", "insert")
+            raw, effective = classifyws(prefix, self.tabwidth)
+            if raw == len(prefix):
+                # only whitespace to the left
+                self.reindent_to(effective + self.indentwidth)
+            else:
+                if self.usetabs:
+                    pad = '\t'
+                else:
+                    effective = len(string.expandtabs(prefix,
+                                                      self.tabwidth))
+                    n = self.indentwidth
+                    pad = ' ' * (n - effective % n)
+                text.insert("insert", pad)
+            text.see("insert")
+            return "break"
+        finally:
+            text.undo_block_stop()
+
+    def newline_and_indent_event(self, event):
+        text = self.text
+        first, last = self.editwin.get_selection_indices()
+        text.undo_block_start()
+        try:
+            if first and last:
+                text.delete(first, last)
+                text.mark_set("insert", first)
+            line = text.get("insert linestart", "insert")
+            i, n = 0, len(line)
+            while i < n and line[i] in " \t":
+                i = i+1
+            if i == n:
+                # the cursor is in or at leading indentation; just inject
+                # an empty line at the start
+                text.insert("insert linestart", '\n')
+                return "break"
+            indent = line[:i]
+            # strip whitespace before insert point
+            i = 0
+            while line and line[-1] in " \t":
+                line = line[:-1]
+                i = i+1
+            if i:
+                text.delete("insert - %d chars" % i, "insert")
+            # strip whitespace after insert point
+            while text.get("insert") in " \t":
+                text.delete("insert")
+            # start new line
+            text.insert("insert", '\n')
+
+            # adjust indentation for continuations and block
+            # open/close first need to find the last stmt
+            lno = index2line(text.index('insert'))
+            y = PyParse.Parser(self.indentwidth, self.tabwidth)
+            for context in self.num_context_lines:
+                startat = max(lno - context, 1)
+                startatindex = `startat` + ".0"
+                rawtext = text.get(startatindex, "insert")
+                y.set_str(rawtext)
+                bod = y.find_good_parse_start(
+                          self.context_use_ps1,
+                          self._build_char_in_string_func(startatindex))
+                if bod is not None or startat == 1:
+                    break
+            y.set_lo(bod or 0)
+            c = y.get_continuation_type()
+            if c != PyParse.C_NONE:
+                # The current stmt hasn't ended yet.
+                if c == PyParse.C_STRING:
+                    # inside a string; just mimic the current indent
+                    text.insert("insert", indent)
+                elif c == PyParse.C_BRACKET:
+                    # line up with the first (if any) element of the
+                    # last open bracket structure; else indent one
+                    # level beyond the indent of the line with the
+                    # last open bracket
+                    self.reindent_to(y.compute_bracket_indent())
+                elif c == PyParse.C_BACKSLASH:
+                    # if more than one line in this stmt already, just
+                    # mimic the current indent; else if initial line
+                    # has a start on an assignment stmt, indent to
+                    # beyond leftmost =; else to beyond first chunk of
+                    # non-whitespace on initial line
+                    if y.get_num_lines_in_stmt() > 1:
+                        text.insert("insert", indent)
+                    else:
+                        self.reindent_to(y.compute_backslash_indent())
+                else:
+                    assert 0, "bogus continuation type " + `c`
+                return "break"
+
+            # This line starts a brand new stmt; indent relative to
+            # indentation of initial line of closest preceding
+            # interesting stmt.
+            indent = y.get_base_indent_string()
+            text.insert("insert", indent)
+            if y.is_block_opener():
+                self.smart_indent_event(event)
+            elif indent and y.is_block_closer():
+                self.smart_backspace_event(event)
+            return "break"
+        finally:
+            text.see("insert")
+            text.undo_block_stop()
+
+    auto_indent = newline_and_indent_event
+
+    # Our editwin provides a is_char_in_string function that works
+    # with a Tk text index, but PyParse only knows about offsets into
+    # a string. This builds a function for PyParse that accepts an
+    # offset.
+
+    def _build_char_in_string_func(self, startindex):
+        def inner(offset, _startindex=startindex,
+                  _icis=self.editwin.is_char_in_string):
+            return _icis(_startindex + "+%dc" % offset)
+        return inner
+
+    def indent_region_event(self, event):
+        head, tail, chars, lines = self.get_region()
+        for pos in range(len(lines)):
+            line = lines[pos]
+            if line:
+                raw, effective = classifyws(line, self.tabwidth)
+                effective = effective + self.indentwidth
+                lines[pos] = self._make_blanks(effective) + line[raw:]
+        self.set_region(head, tail, chars, lines)
+        return "break"
+
+    def dedent_region_event(self, event):
+        head, tail, chars, lines = self.get_region()
+        for pos in range(len(lines)):
+            line = lines[pos]
+            if line:
+                raw, effective = classifyws(line, self.tabwidth)
+                effective = max(effective - self.indentwidth, 0)
+                lines[pos] = self._make_blanks(effective) + line[raw:]
+        self.set_region(head, tail, chars, lines)
+        return "break"
+
+    def comment_region_event(self, event):
+        head, tail, chars, lines = self.get_region()
+        for pos in range(len(lines) - 1):
+            line = lines[pos]
+            lines[pos] = '##' + line
+        self.set_region(head, tail, chars, lines)
+
+    def uncomment_region_event(self, event):
+        head, tail, chars, lines = self.get_region()
+        for pos in range(len(lines)):
+            line = lines[pos]
+            if not line:
+                continue
+            if line[:2] == '##':
+                line = line[2:]
+            elif line[:1] == '#':
+                line = line[1:]
+            lines[pos] = line
+        self.set_region(head, tail, chars, lines)
+
+    def tabify_region_event(self, event):
+        head, tail, chars, lines = self.get_region()
+        tabwidth = self._asktabwidth()
+        for pos in range(len(lines)):
+            line = lines[pos]
+            if line:
+                raw, effective = classifyws(line, tabwidth)
+                ntabs, nspaces = divmod(effective, tabwidth)
+                lines[pos] = '\t' * ntabs + ' ' * nspaces + line[raw:]
+        self.set_region(head, tail, chars, lines)
+
+    def untabify_region_event(self, event):
+        head, tail, chars, lines = self.get_region()
+        tabwidth = self._asktabwidth()
+        for pos in range(len(lines)):
+            lines[pos] = string.expandtabs(lines[pos], tabwidth)
+        self.set_region(head, tail, chars, lines)
+
+    def toggle_tabs_event(self, event):
+        if self.editwin.askyesno(
+              "Toggle tabs",
+              "Turn tabs " + ("on", "off")[self.usetabs] + "?",
+              parent=self.text):
+            self.usetabs = not self.usetabs
+        return "break"
+
+    # XXX this isn't bound to anything -- see class tabwidth comments
+    def change_tabwidth_event(self, event):
+        new = self._asktabwidth()
+        if new != self.tabwidth:
+            self.tabwidth = new
+            self.set_indentation_params(0, guess=0)
+        return "break"
+
+    def change_indentwidth_event(self, event):
+        new = self.editwin.askinteger(
+                  "Indent width",
+                  "New indent width (1-16)",
+                  parent=self.text,
+                  initialvalue=self.indentwidth,
+                  minvalue=1,
+                  maxvalue=16)
+        if new and new != self.indentwidth:
+            self.indentwidth = new
+        return "break"
+
+    def get_region(self):
+        text = self.text
+        first, last = self.editwin.get_selection_indices()
+        if first and last:
+            head = text.index(first + " linestart")
+            tail = text.index(last + "-1c lineend +1c")
+        else:
+            head = text.index("insert linestart")
+            tail = text.index("insert lineend +1c")
+        chars = text.get(head, tail)
+        lines = string.split(chars, "\n")
+        return head, tail, chars, lines
+
+    def set_region(self, head, tail, chars, lines):
+        text = self.text
+        newchars = string.join(lines, "\n")
+        if newchars == chars:
+            text.bell()
+            return
+        text.tag_remove("sel", "1.0", "end")
+        text.mark_set("insert", head)
+        text.undo_block_start()
+        text.delete(head, tail)
+        text.insert(head, newchars)
+        text.undo_block_stop()
+        text.tag_add("sel", head, "insert")
+
+    # Make string that displays as n leading blanks.
+
+    def _make_blanks(self, n):
+        if self.usetabs:
+            ntabs, nspaces = divmod(n, self.tabwidth)
+            return '\t' * ntabs + ' ' * nspaces
+        else:
+            return ' ' * n
+
+    # Delete from beginning of line to insert point, then reinsert
+    # column logical (meaning use tabs if appropriate) spaces.
+
+    def reindent_to(self, column):
+        text = self.text
+        text.undo_block_start()
+        if text.compare("insert linestart", "!=", "insert"):
+            text.delete("insert linestart", "insert")
+        if column:
+            text.insert("insert", self._make_blanks(column))
+        text.undo_block_stop()
+
+    def _asktabwidth(self):
+        return self.editwin.askinteger(
+            "Tab width",
+            "Spaces per tab?",
+            parent=self.text,
+            initialvalue=self.tabwidth,
+            minvalue=1,
+            maxvalue=16) or self.tabwidth
+
+    # Guess indentwidth from text content.
+    # Return guessed indentwidth.  This should not be believed unless
+    # it's in a reasonable range (e.g., it will be 0 if no indented
+    # blocks are found).
+
+    def guess_indent(self):
+        opener, indented = IndentSearcher(self.text, self.tabwidth).run()
+        if opener and indented:
+            raw, indentsmall = classifyws(opener, self.tabwidth)
+            raw, indentlarge = classifyws(indented, self.tabwidth)
+        else:
+            indentsmall = indentlarge = 0
+        return indentlarge - indentsmall
+
+# "line.col" -> line, as an int
+def index2line(index):
+    return int(float(index))
+
+# Look at the leading whitespace in s.
+# Return pair (# of leading ws characters,
+#              effective # of leading blanks after expanding
+#              tabs to width tabwidth)
+
+def classifyws(s, tabwidth):
+    raw = effective = 0
+    for ch in s:
+        if ch == ' ':
+            raw = raw + 1
+            effective = effective + 1
+        elif ch == '\t':
+            raw = raw + 1
+            effective = (effective / tabwidth + 1) * tabwidth
+        else:
+            break
+    return raw, effective
+
+import tokenize
+_tokenize = tokenize
+del tokenize
+
+class IndentSearcher:
+
+    # .run() chews over the Text widget, looking for a block opener
+    # and the stmt following it.  Returns a pair,
+    #     (line containing block opener, line containing stmt)
+    # Either or both may be None.
+
+    def __init__(self, text, tabwidth):
+        self.text = text
+        self.tabwidth = tabwidth
+        self.i = self.finished = 0
+        self.blkopenline = self.indentedline = None
+
+    def readline(self):
+        if self.finished:
+            return ""
+        i = self.i = self.i + 1
+        mark = `i` + ".0"
+        if self.text.compare(mark, ">=", "end"):
+            return ""
+        return self.text.get(mark, mark + " lineend+1c")
+
+    def tokeneater(self, type, token, start, end, line,
+                   INDENT=_tokenize.INDENT,
+                   NAME=_tokenize.NAME,
+                   OPENERS=('class', 'def', 'for', 'if', 'try', 'while')):
+        if self.finished:
+            pass
+        elif type == NAME and token in OPENERS:
+            self.blkopenline = line
+        elif type == INDENT and self.blkopenline:
+            self.indentedline = line
+            self.finished = 1
+
+    def run(self):
+        save_tabsize = _tokenize.tabsize
+        _tokenize.tabsize = self.tabwidth
+        try:
+            try:
+                _tokenize.tokenize(self.readline, self.tokeneater)
+            except _tokenize.TokenError:
+                # since we cut off the tokenizer early, we can trigger
+                # spurious errors
+                pass
+        finally:
+            _tokenize.tabsize = save_tabsize
+        return self.blkopenline, self.indentedline