wrap_plus.py

import sublime
import sublime_plugin
from .wrap import py_textwrap as textwrap
import re
import time
try:
    import Default.comment as comment
except ImportError:
    import comment


def is_quoted_string(scope_r, scope_name):
    # string.quoted.double.block.python
    # string.quoted.single.block.python
    # string.quoted.double.single-line.python
    # string.quoted.single.single-line.python
    # comment.block.documentation.python
    return 'quoted' in scope_name or 'comment.block.documentation' in scope_name


debug_enabled = False
time_start = 0
last_time = 0


def debug_start(enabled):
    global debug_enabled, time_start, last_time
    debug_enabled = enabled
    if debug_enabled:
        time_start = time.time()
        last_time = time_start


def debug(msg, *args):
    if debug_enabled:
        global last_time
        t = time.time()
        d = t - time_start
        print('%.3f (+%.3f) ' % (d, t - last_time), end='')
        last_time = t
        print(msg % args)


def debug_end():
    if debug_enabled:
        print('Total time: %.3f' % (time.time() - time_start))


class PrefixStrippingView(object):
    """View that strips out prefix characters, like comments.

    :ivar str required_comment_prefix: When inside a line comment, we want to
        restrict wrapping to just the comment section, and also retain the
        comment characters and any initial indentation.  This string is the
        set of prefix characters a line must have to be a candidate for
        wrapping in that case (otherwise it is typically the empty string).

    :ivar Pattern required_comment_pattern: Regular expression required for
        matching.  The pattern is already included from the first line in
        `required_comment_prefix`.  This pattern is set to check if subsequent
        lines have longer matches (in which case `line` will stop reading).
    """
    required_comment_prefix = ''
    required_comment_pattern = None

    def __init__(self, view, min, max):
        self.view = view
        self.min = min
        self.max = max

    def _is_c_comment(self, scope_name):
        if 'comment' not in scope_name and 'block' not in scope_name:
            return False
        for c in self.bc:
            if c[0] == '/*' and c[1] == '*/':
                break
        else:
            return False
        return True

    def set_comments(self, lc, bc, pt):
        self.lc = lc
        self.bc = bc
        # If the line at pt is a comment line, set required_comment_prefix to
        # the comment prefix.
        self.required_comment_prefix = ''
        # Grab the line.
        line_r = self.view.line(pt)
        line = self.view.substr(line_r)
        line_strp = line.strip()
        if not line_strp:
            # Empty line, nothing to do.
            debug('Empty line, no comment characters found.')
            return

        # Determine if pt is inside a "line comment".
        # Only whitespace is allowed to the left of the line comment.
        # XXX: What is disable_indent?
        for c in lc:
            start = c[0].rstrip()
            if line_strp.startswith(start):
                ldiff = len(line) - len(line.lstrip())
                p = line[:ldiff + len(start)]
                if (self.required_comment_prefix is None
                    or len(self.required_comment_prefix) < len(p)
                   ):
                    self.required_comment_prefix = p

        # TODO: re.escape required_comment_prefix.

        # Handle email-style quoting.
        email_quote_pattern = re.compile('^' + self.required_comment_prefix + email_quote)
        m = email_quote_pattern.match(line)
        if m:
            self.required_comment_prefix = m.group()
            self.required_comment_pattern = email_quote_pattern
            debug('doing email style quoting')

        scope_r = self.view.extract_scope(pt)
        scope_name = self.view.scope_name(pt)
        if 'comment.block.documentation.summary.python' in scope_name:
            # Recent versions of the Python syntax have a different scope for
            # the first line of a docstring. This causes problems when
            # wrapping the first line. This extends the scope to encompass the
            # entire docstring. (I'm not sure why there is a summary scope.)
            scope_r = self.view.expand_to_scope(pt, 'comment.block')
        debug('scope=%r range=%r', scope_name, scope_r)

        if self._is_c_comment(scope_name):
            # Check for C-style commenting with each line starting with an asterisk.
            first_star_prefix = None
            lines = self.view.lines(scope_r)
            for line_r in lines[1:-1]:
                line = self.view.substr(line_r)
                m = funny_c_comment_pattern.match(line)
                if m is not None:
                    if first_star_prefix is None:
                        first_star_prefix = m.group()
                else:
                    first_star_prefix = None
                    break
            if first_star_prefix:
                self.required_comment_prefix = first_star_prefix
            # Narrow the scope to just the comment contents.
            scope_text = self.view.substr(scope_r)
            m = re.match(r'^([ \t\n]*/\*).*(\*/[ \t\n]*)$', scope_text, re.DOTALL)
            if m:
                begin = scope_r.begin() + len(m.group(1))
                end = scope_r.end() - len(m.group(2))
                self.min = max(self.min, begin)
                self.max = min(self.max, end)
            debug('Scope narrowed to %i:%i', self.min, self.max)

        debug('required_comment_prefix determined to be %r', self.required_comment_prefix,)

        # Narrow the min/max range if inside a "quoted" string.
        if is_quoted_string(scope_r, scope_name):
            # Narrow the range.
            self.min = max(self.min, self.view.line(scope_r.begin()).begin())
            self.max = min(self.max, self.view.line(scope_r.end()).end())

    def line(self, where):
        """Get a line for a point.

        :returns: A (region, str) tuple.  str has the comment prefix stripped.
            Returns None, None if line out of range.
        """
        line_r = self.view.line(where)
        if line_r.begin() < self.min:
            debug('line min increased')
            line_r = sublime.Region(self.min, line_r.end())
        if line_r.end() > self.max:
            debug('line max lowered')
            line_r = sublime.Region(line_r.begin(), self.max)
        line = self.view.substr(line_r)
        debug('line=%r', line)
        if self.required_comment_prefix:
            debug('checking required comment prefix %r', self.required_comment_prefix)

            if line.startswith(self.required_comment_prefix):
                # Check for an insufficient prefix.
                if self.required_comment_pattern:
                    m = self.required_comment_pattern.match(line)
                    if m:
                        if m.group() != self.required_comment_prefix:
                            # This might happen, if for example with an email
                            # comment, we go from one comment level to a
                            # deeper one (the regex matched more > characters
                            # than are in required_comment_pattern).
                            return None, None
                    else:
                        # This should never happen (matches the string but not
                        # the regex?).
                        return None, None
                rcp_len = len(self.required_comment_prefix)
                line = line[rcp_len:]
                # XXX: Should this also update line_r?
            else:
                return None, None
        return line_r, line

    def substr(self, r):
        return self.view.substr(r)

    def next_line(self, where):
        l_r = self.view.line(where)
        debug('next line region=%r', l_r)
        pt = l_r.end() + 1
        if pt >= self.max:
            debug('past max at %r', self.max)
            return None, None
        return self.line(pt)

    def prev_line(self, where):
        l_r = self.view.line(where)
        pt = l_r.begin() - 1
        if pt <= self.min:
            return None, None
        return self.line(pt)


def OR(*args):
    return '(?:' + '|'.join(args) + ')'


def CONCAT(*args):
    return '(?:' + ''.join(args) + ')'


blank_line_pattern = re.compile(r'^[\t \n]*$')

# This doesn't always work, but seems decent.
numbered_list = r'(?:(?:([0-9#]+)[.)])+[\t ])'
numbered_list_pattern = re.compile(numbered_list)
lettered_list = r'(?:[a-zA-Z][.)][\t ])'
bullet_list = r'(?:[*+#-]+[\t ])'
list_pattern = re.compile(r'^[ \t]*' + OR(numbered_list, lettered_list, bullet_list) + r'[ \t]*')
latex_hack = r'(?:\\)(?!,|;|&|%|text|emph|cite|\w?(page)?ref|url|footnote|(La)*TeX)'
rest_directive = r'(?:\.\.)'
field_start = r'(?:[:@])'  # rest, javadoc, jsdoc, etc.
new_paragraph_pattern = re.compile(
    r'^[\t ]*' + OR(lettered_list, bullet_list, field_start))
space_prefix_pattern = re.compile(r'^[ \t]*')
# XXX: Does not handle escaped colons in field name.
fields = OR(r':[^:]+:', '@[a-zA-Z]+ ')
field_pattern = re.compile(r'^([ \t]*)' + fields)  # rest, javadoc, jsdoc, etc

sep_chars = '!@#$%^&*=+`~\'\":;.,?_-'
sep_line = '[' + sep_chars + r']+[ \t' + sep_chars + ']*'

# Break pattern is a little ambiguous.  Something like "# Header" could also be a list element.
break_pattern = re.compile(r'^[\t ]*' + OR(sep_line, OR(latex_hack, rest_directive) + '.*') + '$')
pure_break_pattern = re.compile(r'^[\t ]*' + sep_line + '$')

email_quote = r'[\t ]*>[> \t]*'
funny_c_comment_pattern = re.compile(r'^[\t ]*\*')


class WrapLinesPlusCommand(sublime_plugin.TextCommand):

    def _my_full_line(self, region):
        # Special case scenario where you select an entire line.  The normal
        # "full_line" function will extend it to contain the next line
        # (because the cursor is actually at the beginning of the next line).
        # I would prefer it didn't do that.
        if self.view.substr(region.end() - 1) == '\n':
            return self.view.full_line(sublime.Region(region.begin(), region.end() - 1))
        else:
            return self.view.full_line(region)

    def _is_real_numbered_list(self, line_r, line, limit=10, indent=False):
        """Returns True if `line` is not a paragraph continuation."""
        # We stop checking the list after `limit` lines to avoid quadratic
        # runtime. For inputs like 100 lines of "2. ", this function is called
        # in a loop over the input and also contains a loop over the input.
        # indent tracks whether we came from an indented line
        if limit == 0:
            return True
        m = numbered_list_pattern.search(line)
        if m and m.group(1) == '1':
            return True
        prev_line_r, prev_line = self._strip_view.prev_line(line_r)
        if prev_line_r is None:
            return not indent
        if self._is_paragraph_break(prev_line_r, prev_line):
            return not indent
        if new_paragraph_pattern.match(prev_line):
            return not indent
        if prev_line[0] == ' ' or prev_line[0] == '\t':
            # prev_line might be a numbered list or a normal paragraph
            return self._is_real_numbered_list(prev_line_r, prev_line, limit - 1, indent=True)
        if numbered_list_pattern.match(prev_line):
            return self._is_real_numbered_list(prev_line_r, prev_line, limit - 1)
        return False  # previous line appears to be a normal paragraph

    def _is_paragraph_start(self, line_r, line):
        # Certain patterns at the beginning of the line indicate this is the
        # beginning of a paragraph.
        if new_paragraph_pattern.match(line):
            return True
        if numbered_list_pattern.match(line):
            result = self._is_real_numbered_list(line_r, line)
            debug('is {}a paragraph continuation'.format('not ' if result else ''))
            return result
        return False

    def _is_paragraph_break(self, line_r, line, pure=False):
        """A paragraph "break" is something like a blank line, or a horizontal line,
        or anything that  should not be wrapped and treated like a blank line
        (i.e. ignored).
        """
        if self._is_blank_line(line):
            return True
        scope_name = self.view.scope_name(line_r.begin())
        debug('scope_name=%r (%r)', scope_name, line_r)
        if 'heading' in scope_name:
            return True
        if pure:
            return pure_break_pattern.match(line) is not None
        else:
            return break_pattern.match(line) is not None

    def _is_blank_line(self, line):
        return blank_line_pattern.match(line) is not None

    def _find_paragraph_start(self, pt):
        """Start at pt and move up to find where the paragraph starts.

        :returns: The (line, line_region) of the start of the paragraph.
        """
        view = self._strip_view
        current_line_r, current_line = view.line(pt)
        if current_line_r is None:
            return None, None
        started_in_comment = self._started_in_comment(pt)

        debug('is_paragraph_break?')
        if self._is_paragraph_break(current_line_r, current_line):
            return current_line_r, current_line
        debug('no')

        while 1:
            # Check if this line is the start of a paragraph.
            debug('start?')
            if self._is_paragraph_start(current_line_r, current_line):
                debug('current_line is paragraph start: %r', current_line,)
                break
            # Check if the previous line is a "break" separator.
            debug('break?')
            prev_line_r, prev_line = view.prev_line(current_line_r)
            if prev_line_r is None:
                # current_line is as far up as we're allowed to go.
                break
            if self._is_paragraph_break(prev_line_r, prev_line):
                debug('prev line %r is a paragraph break', prev_line,)
                break
            # If the previous line has a comment, and we started in a
            # non-comment scope, stop.  No need to check for comment to
            # non-comment change because the prefix restrictions should handle
            # that.
            if (not started_in_comment
                and self.view.score_selector(prev_line_r.end(), 'comment')
               ):
                debug('prev line contains a comment, cannot continue.')
                break
            debug('prev_line %r is part of the paragraph', prev_line,)
            # Previous line is a part of this paragraph.  Add it, and loop
            # around again.
            current_line_r = prev_line_r
            current_line = prev_line
        return current_line_r, current_line

    def _find_paragraphs(self, sr):
        """Find and return a list of paragraphs as regions.

        :param Region sr: The region where to look for paragraphs.  If it is
            an empty region, "discover" where the paragraph starts and ends.
            Otherwise, the region defines the max and min (with potentially
            several paragraphs contained within).

        :returns: A list of (region, lines, comment_prefix) of each paragraph.
        """
        result = []
        debug('find paragraphs sr=%r', sr,)
        if sr.empty():
            is_empty = True
            view_min = 0
            view_max = self.view.size()
        else:
            is_empty = False
            full_sr = self._my_full_line(sr)
            view_min = full_sr.begin()
            view_max = full_sr.end()
        started_in_comment = self._started_in_comment(sr.begin())
        self._strip_view = PrefixStrippingView(self.view, view_min, view_max)
        view = self._strip_view
        # Loop for each paragraph (only loops once if sr is empty).
        paragraph_start_pt = sr.begin()
        while 1:
            debug('paragraph scanning start %r.', paragraph_start_pt,)
            view.set_comments(self._lc, self._bc, paragraph_start_pt)
            lines = []
            if is_empty:
                # Find the beginning of this paragraph.
                debug('empty sel finding paragraph start.')
                current_line_r, current_line = self._find_paragraph_start(paragraph_start_pt)
                debug('empty sel paragraph start determined to be %r %r',
                      current_line_r, current_line)
            else:
                # The selection defines the beginning.
                current_line_r, current_line = view.line(paragraph_start_pt)
                debug('sel beggining = %r %r', current_line_r, current_line)

            if current_line_r is None:
                debug('Could not find start.')
                return []

            # Skip blank and unambiguous break lines.
            while 1:
                debug('skip blank line')
                if not self._is_paragraph_break(current_line_r, current_line, pure=True):
                    debug('not paragraph break')
                    break
                if is_empty:
                    debug('empty sel on paragraph break %r', current_line,)
                    return []
                current_line_r, current_line = view.next_line(current_line_r)

            paragraph_start_pt = current_line_r.begin()
            paragraph_end_pt = current_line_r.end()
            # current_line_r now points to the beginning of the paragraph.
            # Move down until the end of the paragraph.
            debug('Scan until end of paragraph.')
            while 1:
                debug('current_line_r=%r max=%r', current_line_r, view.max)
                # If we started in a non-comment scope, and the end of the
                # line contains a comment, include any non-comment text in the
                # wrap and stop looking for more.
                if (not started_in_comment
                    and self.view.score_selector(current_line_r.end(), 'comment')
                   ):
                    debug('end of paragraph hit a comment.')
                    # Find the start of the comment.
                    # This assumes comments do not have multiple scopes.
                    comment_r = self.view.extract_scope(current_line_r.end())
                    # Just in case something is wonky with the scope.
                    end_pt = max(comment_r.begin(), current_line_r.begin())
                    # A substring of current_line.
                    subline_r = sublime.Region(current_line_r.begin(), end_pt)
                    subline = self.view.substr(subline_r)
                    # Do not include whitespace preceding the comment.
                    m = re.search('([ \t]+$)', subline)
                    if m:
                        end_pt -= len(m.group(1))
                    debug('non-comment contents are: %r', subline)
                    paragraph_end_pt = end_pt
                    lines.append(subline)
                    # Skip over the comment.
                    current_line_r, current_line = view.next_line(current_line_r)
                    break

                lines.append(current_line)
                paragraph_end_pt = current_line_r.end()

                current_line_r, current_line = view.next_line(current_line_r)
                if current_line_r is None:
                    # Line is outside of our range.
                    debug('Out of range, stopping.')
                    break
                debug('current_line = %r %r', current_line_r, current_line)
                if self._is_paragraph_break(current_line_r, current_line):
                    debug('current line is a break, stopping.')
                    break
                if self._is_paragraph_start(current_line_r, current_line):
                    debug('current line is a paragraph start, stopping.')
                    break

            paragraph_r = sublime.Region(paragraph_start_pt, paragraph_end_pt)
            result.append((paragraph_r, lines, view.required_comment_prefix))

            if is_empty:
                break

            # Skip over blank lines and break lines till the next paragraph
            # (or end of range).
            debug('skip over blank lines')
            while current_line_r is not None:
                if self._is_paragraph_start(current_line_r, current_line):
                    break
                if not self._is_paragraph_break(current_line_r, current_line):
                    break
                # It's a paragraph break, skip over it.
                current_line_r, current_line = view.next_line(current_line_r)

            if current_line_r is None:
                break

            debug('next_paragraph_start is %r %r', current_line_r, current_line)
            paragraph_start_pt = current_line_r.begin()
            if paragraph_start_pt >= view_max:
                break

        return result

    def _determine_width(self, width):
        """Determine the maximum line width.

        :param Int width: The width specified by the command.  Normally 0
            which means "figure it out".

        :returns: The maximum line width.
        """

        if width == 0:
            try:
                width = int(self.view.settings().get('wrap_width'))
            except (TypeError, ValueError):
                pass

        if width == 0:
            # try and guess the wrap width from the first ruler, if any
            rulers = self.view.settings().get('rulers')
            if isinstance(rulers, list) and len(rulers) > 0:
                # use first ruler
                ruler = rulers[0]
                # extract column from rulers like [80, "solid"]
                if isinstance(ruler, list) and len(ruler) > 0:
                    ruler = ruler[0]
                # ensure integer
                try:
                    width = int(ruler)
                except (TypeError, ValueError):
                    pass

        width = self.view.settings().get('WrapPlus.wrap_width', width)

        # Value of 0 means 'automatic'.
        if width == 0:
            width = 78

        ile = self.view.settings().get('WrapPlus.include_line_endings', 'auto')
        if ile is True:
            width -= self._determine_line_ending_size()
        elif ile == 'auto':
            if self._auto_word_wrap_enabled() and self.view.settings().get('wrap_width', 0) != 0:
                width -= self._determine_line_ending_size()

        return width

    def _determine_line_ending_size(self):
        # Sublime always uses 1, regardless of the file type/OS.
        return 1
        etypes = {
            'windows': 2,
            'unix': 1,
            'cr': 1,
        }
        return etypes.get(self.view.line_endings().lower(), 1)

    def _auto_word_wrap_enabled(self):
        ww = self.view.settings().get('word_wrap')
        return (ww is True or
                (ww == 'auto' and self.view.score_selector(0, 'text')))

    def _determine_tab_size(self):
        tab_width = 8
        if self.view.settings().get('tab_size'):
            try:
                tab_width = int(self.view.settings().get('tab_size'))
            except TypeError:
                pass

        if tab_width == 0:
            tab_width = 8
        self._tab_width = tab_width

    def _determine_comment_style(self):
        # I'm not exactly sure why this function needs a point.  It seems to
        # return the same value regardless of location for the stuff I've
        # tried.
        (self._lc, self._bc) = comment.build_comment_data(self.view, 0)

    def _started_in_comment(self, point):
        if self.view.score_selector(point, 'comment'):
            return True
        # Check for case where only whitespace is before a comment.
        line_r = self.view.line(point)
        if self.view.score_selector(line_r.end(), 'comment'):
            line = self.view.substr(line_r)
            m = re.search('(^[ \t]+)', line)
            if m:
                pt_past_space = line_r.begin() + len(m.group(1))
                if self.view.score_selector(pt_past_space, 'comment'):
                    return True
        return False

    def _width_in_spaces(self, text):
        tab_count = text.count('\t')
        return tab_count * self._tab_width + len(text) - tab_count

    def _make_indent(self):
        # This is suboptimal.
        return ' ' * 4
        # if self.view.settings().get('translate_tabs_to_spaces'):
        #     return ' ' * self._tab_width
        # else:
        #     return '\t'

    def _extract_prefix(self, paragraph_r, lines, required_comment_prefix):
        # The comment prefix has already been stripped from the lines.
        # If the first line starts with a list-like thing, then that will be the initial prefix.
        initial_prefix = ''
        subsequent_prefix = ''
        first_line = lines[0]
        m = list_pattern.match(first_line)
        if m:
            initial_prefix = first_line[0:m.end()]
            stripped_prefix = initial_prefix.lstrip()
            leading_whitespace = initial_prefix[:len(initial_prefix) - len(stripped_prefix)]
            subsequent_prefix = leading_whitespace + ' ' * self._width_in_spaces(stripped_prefix)
        else:
            m = field_pattern.match(first_line)
            if m:
                # The spaces in front of the field start.
                initial_prefix = m.group(1)
                if len(lines) > 1:
                    # How to handle subsequent lines.
                    m = space_prefix_pattern.match(lines[1])
                    if m:
                        # It's already indented, keep this indent level
                        # (unless it is less than where the field started).
                        spaces = m.group(0)
                        if (self._width_in_spaces(spaces) >=
                            self._width_in_spaces(initial_prefix) + 1
                           ):
                            subsequent_prefix = spaces
                if not subsequent_prefix:
                    # Not already indented, make an indent.
                    subsequent_prefix = initial_prefix + self._make_indent()
            else:
                m = space_prefix_pattern.match(first_line)
                if m:
                    initial_prefix = first_line[0:m.end()]
                    if len(lines) > 1:
                        m = space_prefix_pattern.match(lines[1])
                        if m:
                            subsequent_prefix = lines[1][0:m.end()]
                        else:
                            subsequent_prefix = ''
                    else:
                        subsequent_prefix = initial_prefix
                else:
                    # Should never happen.
                    initial_prefix = ''
                    subsequent_prefix = ''

        pt = paragraph_r.begin()
        scope_r = self.view.extract_scope(pt)
        scope_name = self.view.scope_name(pt)
        if len(lines) == 1 and is_quoted_string(scope_r, scope_name):
            # A multi-line quoted string, that is currently only on one line.
            # This is mainly for Python docstrings.  Not sure if it's a
            # problem in other cases.
            true_first_line_r = self.view.line(pt)
            true_first_line = self.view.substr(true_first_line_r)
            if true_first_line_r.begin() <= scope_r.begin():
                m = space_prefix_pattern.match(true_first_line)
                debug('single line quoted string triggered')
                if m:
                    subsequent_prefix = m.group() + subsequent_prefix

        # Remove the prefixes that are there.
        new_lines = []
        new_lines.append(first_line[len(initial_prefix):].strip())
        for line in lines[1:]:
            if line.startswith(subsequent_prefix):
                line = line[len(subsequent_prefix):]
            new_lines.append(line.strip())

        debug('initial_prefix=%r subsequent_prefix=%r', initial_prefix, subsequent_prefix)

        return (required_comment_prefix + initial_prefix,
                required_comment_prefix + subsequent_prefix,
                new_lines)

    def run(self, edit, width=0):
        debug_start(self.view.settings().get('WrapPlus.debug', False))
        debug('#########################################################################')
        self._width = self._determine_width(width)
        debug('wrap width = %r', self._width)
        self._determine_tab_size()
        self._determine_comment_style()

        # paragraphs is a list of (region, lines, comment_prefix) tuples.
        paragraphs = []
        for s in self.view.sel():
            debug('examine %r', s)
            paragraphs.extend(self._find_paragraphs(s))

        debug('paragraphs is %r', paragraphs)

        if paragraphs:
            # Use view selections to handle shifts from the replace() command.
            self.view.sel().clear()
            for r, l, p in paragraphs:
                self.view.sel().add(r)

            # Regions fetched from view.sel() will shift appropriately with
            # the calls to replace().
            for i, s in enumerate(self.view.sel()):
                paragraph_r, paragraph_lines, required_comment_prefix = paragraphs[i]
                break_long_words = self.view.settings().get('WrapPlus.break_long_words', False)
                break_on_hyphens = self.view.settings().get('WrapPlus.break_on_hyphens', False)
                wrapper = textwrap.TextWrapper(break_long_words=break_long_words,
                                               break_on_hyphens=break_on_hyphens)
                wrapper.width = self._width
                init_prefix, subsequent_prefix, paragraph_lines = self._extract_prefix(
                    paragraph_r, paragraph_lines, required_comment_prefix)
                orig_init_prefix = init_prefix
                orig_subsequent_prefix = subsequent_prefix
                if orig_init_prefix or orig_subsequent_prefix:
                    # Textwrap is somewhat limited.  It doesn't recognize tabs
                    # in prefixes.  Unfortunately, this means we can't easily
                    # differentiate between the initial and subsequent.  This
                    # is a workaround.
                    init_prefix = orig_init_prefix.expandtabs(self._tab_width)
                    subsequent_prefix = orig_subsequent_prefix.expandtabs(self._tab_width)
                    wrapper.initial_indent = init_prefix
                    wrapper.subsequent_indent = subsequent_prefix

                wrapper.expand_tabs = False

                txt = '\n'.join(paragraph_lines)
                txt = txt.expandtabs(self._tab_width)
                txt = wrapper.fill(txt)

                # Put the tabs back to the prefixes.
                if orig_init_prefix or orig_subsequent_prefix:
                    if (init_prefix != orig_subsequent_prefix
                        or subsequent_prefix != orig_subsequent_prefix
                       ):
                        lines = txt.splitlines()
                        if init_prefix != orig_init_prefix:
                            debug('fix tabs %r', lines[0])
                            lines[0] = orig_init_prefix + lines[0][len(init_prefix):]
                            debug('new line is %r', lines[0])
                        if subsequent_prefix != orig_subsequent_prefix:
                            for i, line in enumerate(lines[1:]):
                                rest = lines[i + 1][len(subsequent_prefix):]
                                lines[i + 1] = orig_subsequent_prefix + rest
                        txt = '\n'.join(lines)

                replaced_txt = self.view.substr(s)
                # I can't decide if I prefer it to not make the modification
                # if there is no change (and thus don't mark an unmodified
                # file as modified), or if it's better to include a "non-
                # change" in the undo stack.
                self.view.replace(edit, s, txt)
                if replaced_txt != txt:
                    debug('replaced text not the same:\noriginal=%r\nnew=%r', replaced_txt, txt)
                else:
                    debug('replaced text is the same')

        # Move cursor below the last paragraph.
        s = self.view.sel()
        end = s[len(s) - 1].end()
        line = self.view.line(end)
        end = min(self.view.size(), line.end() + 1)
        self.view.sel().clear()
        r = sublime.Region(end)
        self.view.sel().add(r)
        self.view.show(r)
        debug_end()