pmacs3/method/__init__.py

import os, commands, re, sets, tempfile
from subprocess import Popen, PIPE, STDOUT

import buffer, default, dirutil, regex, util, window
from point import Point

DATATYPES = {
    "path":         None,
    "buffer":       None,
    "method":       None,
    "command":      None,
    "shell":        None,
    "shellcommand": None,
}

class MethodError(Exception):
    pass

class Argument(object):
    def __init__(self, name, type=type(""), datatype=None, prompt=None, help="",
                 default=default.none, load_default=False):
        self.name = name
        self.type = type
        self.datatype = datatype
        if prompt is None:
            self.prompt = "%s: " % (name)
        else:
            self.prompt = prompt
        self.help = help

        self.load_default = load_default
        self.default = default

    def coerce_to_type(self, value):
        if self.type == type(0):
            try:
                return int(value, 0)
            except:
                raise Exception, "expected int; got %s" % (repr(value))
        else:
            return value

    def ask_for_value(self, method, w, **vargs):
        app = w.application
        assert app.mini_buffer_is_open() is False, "Recursive minibuffer antics"
        vargs2 = vargs.copy()
        assert callable(self.default), "default value func must be callable"
        if self.load_default:
            d = None
            starting_value = self.default(w)
        else:
            d = self.default(w)
            starting_value = None
        def return_value(v):
            if d is not None and v == "":
                v = d
            vargs2[self.name] = self.coerce_to_type(v)
            app.close_mini_buffer()
            method.execute(w, **vargs2)
        tabber = DATATYPES.get(self.datatype, None)
        if d is not None:
            p = self.prompt + "(%s) " % (d)
        else:
            p = self.prompt
        app.open_mini_buffer(p, return_value, method, tabber)
        if starting_value:
            app.mini_buffer.set_data(starting_value)
        
class Method(object):
    _is_method = True
    args       = []
    help       = ""
    def __init__(self):
        self.name = self._name()
        self.help = self.__doc__

    def _name(cls):
        s = cls.__name__
        s2 = s[0].lower()
        for c in s[1:]:
            if c.isupper():
                s2 += '-' + c.lower()
            elif c == '_':
                s2 += '-'
            else:
                s2 += c
        return s2
    _name = classmethod(_name)

    def _pre_execute(self, w, **vargs):
        pass

    def execute(self, w, **vargs):
        try:
            self._pre_execute(w, **vargs)
        except MethodError, e:
            w.set_error(str(e))
            return
        for arg in self.args:
            if arg.name not in vargs:
                self.old_window = w
                arg.ask_for_value(self, w, **vargs)
                return
        self._execute(w, **vargs)
        
    def _execute(self, w, **vargs):
        raise Exception, "Unimplemented Method: %s %r" % (self.name, vargs)

class RelexBuffer(Method):
    '''Relex the buffer; this resets syntax highlighting'''    
    def _execute(self, w, **vargs):
        h = w.get_highlighter()
        if h is None:
            w.set_error("No lexer for buffer.")
        else:
            h.highlight(w.buffer.lines)
            w.set_error("Buffer relexed.")

class ToggleWindow(Method):
    '''Move between visible windows'''
    def _execute(self, w, **vargs):
        w.application.toggle_window()

# complex text maniuplation
class TransposeWords(Method):
    '''Switch the place of the two words nearest the cursor'''
    pass

# you wanna quit right?
class Exit(Method):
    '''Exit the program, unless there are unsaved changes'''
    def _execute(self, w, **vargs):
        a = w.application
        assert a.mini_buffer_is_open() is False, "Recursive minibuffer antics"

        changed = False
        for b in w.application.bufferlist.buffers:
            changed = b.changed()
            if changed:
                break
        if not changed:
            w.application.exit()
            return
        else:
            self._old_window = w
            self._prompt = "There are buffers with unsaved changes; exit anyway? "
            a.open_mini_buffer(self._prompt, self._callback)

    def _callback(self, v):
        a = self._old_window.application
        if v == 'yes':
            a.exit()
        a.close_mini_buffer()
        if v == 'no':
            return
        a.open_mini_buffer(self._prompt, self._callback)
        a.set_error('Please type "yes" or "no"')

# insert text
class InsertString(Method):
    _is_method = False
    def __init__(self, s):
        self.name = "insert-string-%s" % s
        self.args = []
        self.help = "Insert %r into the current buffer." % s
        self.string = s
    def _execute(self, w, **vargs):
        w.insert_string_at_cursor(self.string)
class OverwriteChar(Method):
    _is_method = False
    def __init__(self, c):
        self.name = 'overwrite-char-%s' % c
        self.args = []
        self.help = "Overwrite %r into the current buffer." % c
        self.char = c
    def _execute(self, w, **vargs):
        w.overwrite_char_at_cursor(self.char)

# killing/copying/etc.
class Kill(Method):
    '''Kill the contents of the current line'''    
    def _execute(self, w, **vargs):
        w.kill_line()
class KillRegion(Method):
    '''Kill the region between the mark and the cursor'''    
    def _execute(self, w, **vargs):
        w.kill_region()
        w.set_error("Region killed by %s" % self.name)
class Copy(Method):
    '''Copy the contents of the current line'''
    def _execute(self, w, **vargs):
        w.copy_line()
class CopyRegion(Method):
    '''Copy the region between the mark and the cursor'''
    def _execute(self, w, **vargs):
        w.copy_region()
        w.set_active_point(w.mark)
        w.set_error("Region copied")
class Yank(Method):
    '''Paste the top item in the kill ring into the buffer'''
    def _execute(self, w, **vargs):
        if w.application.has_kill():
            w.yank()
        else:
            w.set_error("Kill ring is empty")
class ShowKill(Method):
    '''Display the top item in the kill ring'''
    def _execute(self, w, **vargs):
        if w.application.has_kill():
            s = w.application.get_kill()
            x = w.application.x
            if len(s) > x - 40:
                s = s[:x - 40] + "..."
            w.set_error("Kill ring contains %r" % s)
        else:
            w.set_error("Kill ring is empty")
class PopKill(Method):
    '''Pop the top item in the kill ring off'''
    def _execute(self, w, **vargs):
        if w.application.has_kill():
            s = w.pop_kill()
            x = w.application.x
            if len(s) > x - 40:
                s = s[:x - 40] + "..."
            w.set_error("Removed %r from Kill ring" % s)
        else:
            w.set_error("Kill ring is empty")

# delete
class DeleteLeft(Method):
    '''Delete the character to the left of the cursor'''
    def _execute(self, w, **vargs):
        (x, y) = w.logical_cursor().xy()
        line = w.buffer.lines[y]
        tabwidth = w.mode.tabwidth
        if x >= tabwidth and x % tabwidth == 0 and line[0:x].isspace():
            w.kill(Point(x - tabwidth, y), Point(x, y))
        else:
            w.left_delete()
class DeleteRight(Method):
    '''Delete the character under the cursor'''
    def _execute(self, w, **vargs):
        cursor = w.logical_cursor()
        line = w.buffer.lines[cursor.y]
        if len(line[cursor.x:]) >= 4 and line[:cursor.x + 4].isspace():
            w.kill(Point(cursor.x, cursor.y),
                        Point(cursor.x + 4, cursor.y))
        else:
            w.right_delete()
class DeleteLeftWord(Method):
    '''Delete the from the cursor left to the end of the word'''
    def _execute(self, w, **vargs):
        w.kill_left_word()
class DeleteRightWord(Method):
    '''Delete the from under cursor right to the end of the word'''
    def _execute(self, w, **vargs):
        w.kill_right_word()
class DeleteLeftWhitespace(Method):
    '''Delete all contiguous of whitespace left of the cursor'''
    def _execute(self, w, **vargs):
        c = w.logical_cursor()
        p = c
        l = w.point_left(p)
        if l is None:
            return
        while l is not None and w.point_char(l) in (' ', '\n'):
            p = l
            l = w.point_left(p)
        if p < c:
            w.kill(p, c)
class DeleteRightWhitespace(Method):
    '''Delete all contiguous of whitespace under and right of the cursor'''
    def _execute(self, w, **vargs):
        c = w.logical_cursor()
        p = c
        while w.point_char(p) in (' ', '\n'):
            r = w.point_right(p)
            if r is None:
                break
            p = r
        if p > c:
            w.kill(c, p)
class DeleteLeftSpace(Method):
    '''Delete all contiguous spaces left of the cursor'''
    def _execute(self, w, **vargs):
        c = w.logical_cursor()
        p = c
        l = w.point_left(p)
        if l is None:
            return
        while l is not None and w.point_char(l) == ' ':
            p = l
            l = w.point_left(p)
        if p < c:
            w.kill(p, c)
class DeleteRightSpace(Method):
    '''Delete all contiguous spaces under and right of the cursor'''
    def _execute(self, w, **vargs):
        c = w.logical_cursor()
        p = c
        while w.point_char(p) == ' ':
            r = w.point_right(p)
            if r is None:
                break
            p = r
        if p > c:
            w.kill(c, p)

class MetaX(Method):
    '''Invoke commands by name'''
    args = [Argument('method', datatype="method", prompt="M-x ")]
    def _execute(self, w, **vargs):
        name = vargs['method']
        if name in w.application.methods:
            w.application.methods[name].execute(w)
        else:
            w.set_error('no method named %r found' % name)
            
class ToggleMargins(Method):
    '''Show or hide column margins'''
    def _execute(self, w, **vargs):
        w.margins_visible = not w.margins_visible
class CenterView(Method):
    '''Move view to center on cursor'''
    def _execute(self, w, **vargs):
        w.center_view()
class SetMark(Method):
    '''Set the mark to the current cursor location'''
    def _execute(self, w, **vargs):
        w.set_mark()
class SwitchMark(Method):
    '''Switch the mark and the cursor locations'''
    def _execute(self, w, **vargs):
        w.switch_mark()

# insertion methods
class InsertNewline(Method):
    '''Insert newline into buffer at the cursor'''
    def _execute(self, w, **vargs):
        w.insert_string_at_cursor('\n')
class InsertSpace(Method):
    '''Insert space into buffer at the cursor'''
    def _execute(self, w, **vargs):
        w.insert_string_at_cursor(' ')

class InsertSquotes(Method):
    '''Insert a pair of single-quotes into the buffer'''
    def _execute(self, w, **vargs):
        w.insert_string_at_cursor("''")
        w.backward()
class InsertDquotes(Method):
    '''Insert a pair of double-quotes into the buffer'''
    def _execute(self, w, **vargs):
        w.insert_string_at_cursor('""')
        w.backward()
class InsertEscapedSquote(Method):
    '''Insert an escaped single-quote'''
    def _execute(self, w, **vargs):
        w.insert_string_at_cursor("\\'")
class InsertEscapedDquote(Method):
    '''Insert an escaped double-quote'''
    def _execute(self, w, **vargs):
        w.insert_string_at_cursor('\\"')

class InsertTab(Method):
    '''Insert tab into buffer, or tabbify line, depending on mode'''
    def _execute(self, w, **vargs):
        cursor = w.logical_cursor()
        if w.mode.tabber:
            i = w.mode.tabber.get_level(cursor.y)
        else:
            i = None

        if i is None:
            w.insert_string_at_cursor(' ' * w.mode.tabwidth)
        else:
            j = w.buffer.count_leading_whitespace(cursor.y)
            if i != j:
                KillWhitespace().execute(w)
                w.insert_string(Point(0, cursor.y), ' ' * i)
            else:
                w.goto(Point(j, cursor.y))

class KillWhitespace(Method):
    '''Delete leading whitespace on current line'''
    def _execute(self, w, **vargs):
        cursor = w.logical_cursor()
        i = w.buffer.count_leading_whitespace(cursor.y)
        if i > 0:
            w.kill(Point(0, cursor.y), Point(i, cursor.y))

# tabification
class TabBuffer(Method):
    '''Tabbify every line in the current buffer'''
    def _execute(self, w, **vargs):
        y = w.logical_cursor().y
        it = InsertTab()
        for i in range(0, len(w.buffer.lines)):
            w.goto_line(i)
            it.execute(w)
        w.goto_line(y)
class GetIndentionLevel(Method):
    '''Calculate the indention level for this line'''
    def _execute(self, w, **vargs):
        cursor = w.logical_cursor()
        if not w.mode.tabber:
            w.set_error('No tabber available')
            return
        else:
            i = w.mode.tabber.get_level(cursor.y)
            w.set_error('Indention level: %r' % i)

# commenting
class CommentRegion(Method):
    '''Prepend a comment to every line in the current buffer'''
    def _execute(self, w, **vargs):
        cursor = w.logical_cursor()
        if cursor < w.mark:
            p1 = cursor
            p2 = w.mark
        elif w.mark < cursor:
            p1 = w.mark
            p2 = cursor
        else:
            w.input_line = "Empty kill region"
            return
        for y in range(p1.y, p2.y):
            w.buffer.insert_string(Point(0, y), "#")
class UncommentRegion(Method):
    '''Remove a comment from every line in the current buffer'''
    def _execute(self, w, **vargs):
        cursor = w.logical_cursor()
        if cursor < w.mark:
            p1 = cursor
            p2 = w.mark
        elif w.mark < cursor:
            p1 = w.mark
            p2 = cursor
        else:
            w.input_line = "Empty kill region"
            return
        for y in range(p1.y, p2.y):
            if w.buffer.lines[y].startswith("#"):
                w.buffer.delete(Point(0, y), Point(1, y))

# wrapping/justifying/etc
class WrapLine(Method):
    limit = 80
    space_re = re.compile(' +')
    def _token_len(self, tokens):
        l = 0
        for t in tokens:
            l += len(t)
        return l
    def _find_line_bounds(self, tokens, x, y):
        if len(tokens[0]) > self.limit:
            i = 1
        else:
            i = 0
            l = self._token_len(tokens[:i+1])
            while i < len(tokens) and l <= self.limit:
                i += 1
                l = self._token_len(tokens[:i+1])
            while i > 1 and tokens and tokens[i-1].isspace():
                token = tokens.pop(i-1)
                l -= len(token)
                if x > l:
                    x -= len(token)
                i -= 1
        return i, x, y
    def _clear_preceeding_spaces(self, tokens, x, y):
        while tokens and self.space_re.match(tokens[0]):
            if x > 0:
                x = max(0, x - len(tokens[0]))
            del tokens[0]
        return x, y

    def _wrap_line(self, line, x, y):
        tokens = re.findall('[^ ]+| +', line)
        if self._token_len(tokens) <= self.limit:
            return None, None, None

        lines = []
        while tokens and self._token_len(tokens) > self.limit:
            i, x, y = self._find_line_bounds(tokens, x, y)
            s = ''.join(tokens[:i])
            lines.append(s)
            if x > len(s):
                y += 1
                x -= len(s)
            del tokens[:i]
            x, y = self._clear_preceeding_spaces(tokens, x, y)
        if tokens:
            lines.append(''.join(tokens) + ' ')

        return lines, x, y
    def _execute(self, w, **vargs):
        cursor = w.logical_cursor()
        x, y = cursor.xy()
        lines, x, y = self._wrap_line(w.buffer.lines[y], x, y)
        if lines is None:
            return
        p1 = Point(0, cursor.y)
        p2 = Point(len(w.buffer.lines[cursor.y]), cursor.y)
        w.buffer.delete(p1, p2)
        p3 = Point(0, cursor.y)
        w.buffer.insert_lines(p3, lines)
        w.goto(Point(x, y))
class WrapParagraph(Method):
    limit     = 80
    valid_re  = re.compile('^( *)([^ ].*)$')
    empty_re  = regex.whitespace
    prefix_re = None
    def _execute(self, w, **vargs):
        # we will store the start of our paragaph in p1, and also the original
        # cursor position.
        p1 = oldc = w.logical_cursor()
        cur_offset = 0

        m = self.valid_re.match(w.buffer.lines[p1.y])
        if not m:
            # the line was empty, so return
            return
        elif m.group(1):
            # the line had leading whitespace, so return
            return

        # see if we are starting in the middle of the paragraph; if so, then
        # let's find the actual begining, and update p1 accordingly.
        i = p1.y
        if i > 1 and w.buffer.lines[i] and not w.buffer.lines[i].startswith(' '):
            while i > 1 and w.buffer.lines[i - 1] and not w.buffer.lines[i - 1].startswith(' '):
                i -= 1
            p1 = Point(0, i)

        # get the first line; strip it, and put it in our new lines list.
        s1 = w.buffer.lines[p1.y][p1.x:]
        s2 = s1.rstrip()
        if p1.y <= oldc.y:
            cur_offset += len(s1) - len(s2)
        lines = [s2]

        # ok, so now let's move forward and find the end of the paragraph.
        i = p1.y + 1
        while i < len(w.buffer.lines) and w.buffer.lines[i] and not w.buffer.lines[i].startswith(' '):
            s1 = w.buffer.lines[i]
            s2 = s1.rstrip()
            if oldc.y == i:
                # once we've adjusted all our previous lines, adjust our
                # stored cursor to keep it's X and Y in sync (set Y to the line
                # the paragraph started on, increase X by the previous lines
                # plus added spaces minus removed whitespace.
                x = p1.x + oldc.x + sum([len(x) + 1 for x in lines]) - cur_offset
                oldc = Point(x, p1.y)
            elif i < oldc.y:
                cur_offset += len(s1) - len(s2)
            lines.append(s2)
            i += 1

        # stringify our paragraph
        s = " ".join(lines)

        # ok, so now we need to find the line breaks
        newlines = []
        while s:
            # if we have less than the limit left, add it and we're done!
            if len(s) < self.limit:
                newlines.append(s)
                break

            # look for the rightmost space within our bounds
            j = s.rfind(' ', 0, self.limit)
            # if we failed to find one, look for the leftmost space
            if j == -1:
                j = s.find(' ')
            # if we failed to find any, use the whole rest of the paragraph
            if j == -1:
                j = len(s)
            # add the next chunk we found and adjust the paragraph
            newlines.append(s[:j])
            s = s[j + 1:]

        # translate our cursor according to the line breaks we just did.
        (x, y) = oldc.xy()
        k = 0
        while k < len(newlines) - 1 and x > len(newlines[k]):
            x = x - len(newlines[k]) - 1
            y += 1
            k += 1

        # kill the old paragraph region, insert the new, and goto the new cursor
        w.kill(p1, Point(len(w.buffer.lines[i-1]), i-1))
        w.insert_lines(p1, newlines)
        w.goto(Point(x, y))

class JustifyRight(Method):
    '''Justify text with the previous line right from the cursor by whitespace'''
    def _execute(self, w, **vargs):
        DeleteLeftSpace().execute(w)
        cursor = w.logical_cursor()
        prev_line = w.buffer.lines[cursor.y-1]
        this_line = w.buffer.lines[cursor.y]
        if cursor.y <= 0:
            return
        if cursor.x >= len(prev_line):
            return
        i = cursor.x
        while prev_line[i] != ' ':
            i += 1
            if i >= len(prev_line):
                return
        while prev_line[i] == ' ':
            i += 1
            if i >= len(prev_line):
                return
        s = ' ' * (i - cursor.x)
        w.insert_string_at_cursor(s)
class JustifyLeft(Method):
    '''Justify text with the previous line left from the cursor by whitespace'''
    def _execute(self, w, **vargs):
        DeleteRightWhitespace().execute(w)
        cursor = w.logical_cursor()
        prev_line = w.buffer.lines[cursor.y-1]
        this_line = w.buffer.lines[cursor.y]
        if cursor.y <= 0:
            return
        if cursor.x <= 0:
            return
        i = cursor.x
        while i >= len(prev_line):
            i -= 1
            if i <= 0:
                return
            if this_line[i] != ' ':
                return
        while prev_line[i] != ' ':
            i -= 1
            if i <= 0:
                return
            if this_line[i] != ' ':
                return
        while prev_line[i] == ' ':
            i -= 1
            if i >= len(prev_line):
                return
            if this_line[i] != ' ':
                return
        w.buffer.delete(Point(i, cursor.y), cursor)

# undo/redo
class Undo(Method):
    '''Undo last action'''
    def _execute(self, w, **vargs):
        try:
            w.undo()
        except Exception, e:
            w.set_error("%s" % (e))
class Redo(Method):
    '''Redo last undone action'''
    def _execute(self, w, **vargs):
        try:
            w.redo()
        except Exception, e:
            w.set_error("%s" % (e))

class UnindentBlock(Method):
    '''Prepend 4 spaces to each line in region'''
    def _execute(self, w, **vargs):
        cursor = w.logical_cursor()
        if cursor < w.mark:
            p1 = cursor
            p2 = w.mark
        elif w.mark < cursor:
            p1 = w.mark
            p2 = cursor
        else:
            w.input_line = "Empty kill region"
            return
        lines = w.buffer.lines[p1.y:p2.y]
        for i in range(0, len(lines)):
            if lines[i].startswith('    '):
                lines[i] = lines[i][4:]
        w.buffer.delete(Point(0, p1.y), Point(0, p2.y))
        w.buffer.insert_string(Point(0, p1.y), '\n'.join(lines) + '\n')
class IndentBlock(Method):
    '''Add 4 spaces to each line in region'''
    def _execute(self, w, **vargs):
        cursor = w.logical_cursor()
        if cursor < w.mark:
            p1 = cursor
            p2 = w.mark
        elif w.mark < cursor:
            p1 = w.mark
            p2 = cursor
        else:
            w.input_line = "Empty kill region"
            return
        lines = w.buffer.lines[p1.y:p2.y]
        tstr = ' ' * w.mode.tabwidth
        for i in range(0, len(lines)):
            lines[i] = tstr + lines[i]
        w.buffer.delete(Point(0, p1.y), Point(0, p2.y))
        w.buffer.insert_string(Point(0, p1.y), '\n'.join(lines) + '\n')

class FileDiff(Method):
    '''diff the buffer's contents with the given file'''
    args = [Argument("path", type=type(""), prompt="Filename: ", datatype='path')]
    def _execute(self, w, **vargs):
        cmd = ("/usr/bin/diff", '-u', '-', vargs['path'])
        pipe = Popen(cmd, stdin=PIPE, stdout=PIPE, stderr=PIPE)
        pid = pipe.pid

        indata = w.buffer.make_string()
        pipe.stdin.write(indata)
        pipe.stdin.close()

        outdata = pipe.stdout.read()
        errdata = pipe.stderr.read()
        status = pipe.wait() >> 8

        if status == 0:
            w.set_error("No difference found")
        elif status == 1:
            w.application.data_buffer("*Diff*", outdata, switch_to=True, modename='diff')
            w.set_error("Differences were found")
        else:
            w.application.data_buffer("*Diff*", errdata, switch_to=True)
            w.set_error("There was an error: %d exited with status %s" % (pid, status))

class SetMode(Method):
    '''Set the mode of the current buffer'''
    args = [Argument('mode', datatype='mode', prompt="Enter new mode: ")]
    def _execute(self, w, **vargs):
        mode_name = vargs['mode']
        m = w.application.modes[mode_name](w)
        w.set_mode(m)
        w.set_error('Set mode to %r' % (mode_name))

class Cancel(Method):
    '''Cancel command in-progress, and return to the main buffer'''
    def execute(self, w, **vargs):
        w.application.close_mini_buffer()
        w.set_error('Cancel')

class SplitWindow(Method):
    '''Split the main window horizontally into upper and lower windows'''
    def execute(self, w, **vargs):
        a = w.application
        a.add_slot()
        if not w.cursor_is_visible():
            p = w.first
            w.goto(p)
        n = len(a.bufferlist.slots)
        a.set_error('Window has been split into %d windows!' % n)

class UnsplitWindow(Method):
    '''Maximize the current window to fill the screen'''
    def execute(self, w, **vargs):
        w.application.single_slot()
        w.set_error('Window has been unsplit back to one window!')

class CloseTag(Method):
    mytag     = ')'
    def _execute(self, w, **vargs):
        # first, de-reference some variables and actually do the insertion
        # NOTE: we derence the cursor *before* inserting the character, so it is
        # expecected that the cursor variable should be the point the new
        # character is on.
        (x, y) = w.logical_cursor().xy()
        w.insert_string_at_cursor(self.mytag)
        app         = w.application
        buffer      = w.buffer
        highlighter = buffer.highlights[w.mode.name()]
        tokens      = highlighter.tokens

        # REFACTOR: we have methods in window to do this now
        i = 0
        while i < len(tokens[y]):
            token = tokens[y][i]
            if token.x == x and token.string == self.mytag:
                break
            elif token.x <= x and token.end_x() > x:
                return
            i += 1
        if i >= len(tokens[y]):
            return

        tag_stack = []
        while y >= 0:
            while i >= 0 and i < len(tokens[y]):
                token = tokens[y][i]
                n = token.name
                s = token.string
                if n in w.mode.closetokens and s in w.mode.closetags:
                    tag_stack.append(s)
                elif n in w.mode.opentokens and s in w.mode.opentags:
                    if tag_stack[-1] == w.mode.opentags[s]:
                        del tag_stack[-1]
                    else:
                        app.set_error("tag mismatch; got %r expected %r" %
                                      (s, w.mode.closetags[tag_stack[-1]]))
                        return
                if len(tag_stack) == 0:
                    p = Point(token.x, y)
                    s = w.buffer.lines[p.y][:p.x+1]
                    if len(s) > 60:
                        s = "..." + s[-60:]
                    msg = 'matches %r' % s
                    w.set_active_point(p, msg)
                    return
                i -= 1
            y -= 1
            i = len(tokens[y]) - 1

class CloseParen(CloseTag):
    mytag = ')'
class CloseBrace(CloseTag):
    mytag = '}'
class CloseBracket(CloseTag):
    mytag = ']'

class RegisterSave(Method):
    MAX_TXT = 30
    MAX_REG = 20
    '''Save the top item of the kill stack into the named register'''
    args = [Argument('name', datatype="str", prompt="Register name: ")]
    def _pre_execute(self, w, **vargs):
        if not w.has_kill():
            raise MethodError, "No text on the kill stack"
    def _execute(self, w, **vargs):
        name                          = vargs['name']
        text                          = w.get_kill()
        w.application.registers[name] = text
        if len(name) > self.MAX_REG:
            name = name[:self.MAX_REG] + '...'
        if len(text) > self.MAX_TXT:
            text = text[:self.MAX_TXT] + '...'
        w.set_error('Saved %r into register %r' % (text, name))

class RegisterRestore(Method):
    MAX_TXT = 30
    MAX_REG = 18
    '''Push the value saved in the named register onto the kill stack'''
    args = [Argument('name', datatype="str", prompt="Register name: ")]
    def _execute(self, w, **vargs):
        name = vargs['name']
        if name not in w.application.registers:
            w.set_error('Register %r does not exist' % name)
            return
        text = app.registers[name]
        w.push_kill(text)
        if len(text) > self.MAX_TXT:
            text = text[0:self.MAX_TXT] + '...'
        if len(name) > self.MAX_REG:
            name = name[0:self.MAX_REG] + '...'
        w.set_error('Restored %r from register %r' % (text2, name2))