doc/hgmanpage.py

revlog: avoid an expensive string copy

This showed up in a statprof profile of "hg svn rebuildmeta", which
is read-intensive on the changelog.  This two-line patch improved
the performance of that command by 10%.

# -*- coding: utf-8 -*-
# $Id: manpage.py 6110 2009-08-31 14:40:33Z grubert $
# Author: Engelbert Gruber <[e-mail]>
# Copyright: This module is put into the public domain.

"""
Simple man page writer for reStructuredText.

Man pages (short for "manual pages") contain system documentation on unix-like
systems. The pages are grouped in numbered sections:

 1 executable programs and shell commands
 2 system calls
 3 library functions
 4 special files
 5 file formats
 6 games
 7 miscellaneous
 8 system administration

Man pages are written *troff*, a text file formatting system.

See http://www.tldp.org/HOWTO/Man-Page for a start.

Man pages have no subsection only parts.
Standard parts

  NAME ,
  SYNOPSIS ,
  DESCRIPTION ,
  OPTIONS ,
  FILES ,
  SEE ALSO ,
  BUGS ,

and

  AUTHOR .

A unix-like system keeps an index of the DESCRIPTIONs, which is accesable
by the command whatis or apropos.

"""

__docformat__ = 'reStructuredText'

import re

from docutils import nodes, writers, languages
import roman
import inspect

FIELD_LIST_INDENT = 7
DEFINITION_LIST_INDENT = 7
OPTION_LIST_INDENT = 7
BLOCKQOUTE_INDENT = 3.5

# Define two macros so man/roff can calculate the
# indent/unindent margins by itself
MACRO_DEF = (r""".
.nr rst2man-indent-level 0
.
.de1 rstReportMargin
\\$1 \\n[an-margin]
level \\n[rst2man-indent-level]
level margin: \\n[rst2man-indent\\n[rst2man-indent-level]]
-
\\n[rst2man-indent0]
\\n[rst2man-indent1]
\\n[rst2man-indent2]
..
.de1 INDENT
.\" .rstReportMargin pre:
. RS \\$1
. nr rst2man-indent\\n[rst2man-indent-level] \\n[an-margin]
. nr rst2man-indent-level +1
.\" .rstReportMargin post:
..
.de UNINDENT
. RE
.\" indent \\n[an-margin]
.\" old: \\n[rst2man-indent\\n[rst2man-indent-level]]
.nr rst2man-indent-level -1
.\" new: \\n[rst2man-indent\\n[rst2man-indent-level]]
.in \\n[rst2man-indent\\n[rst2man-indent-level]]u
..
""")

class Writer(writers.Writer):

    supported = ('manpage')
    """Formats this writer supports."""

    output = None
    """Final translated form of `document`."""

    def __init__(self):
        writers.Writer.__init__(self)
        self.translator_class = Translator

    def translate(self):
        visitor = self.translator_class(self.document)
        self.document.walkabout(visitor)
        self.output = visitor.astext()


class Table(object):
    def __init__(self):
        self._rows = []
        self._options = ['center']
        self._tab_char = '\t'
        self._coldefs = []
    def new_row(self):
        self._rows.append([])
    def append_separator(self, separator):
        """Append the separator for table head."""
        self._rows.append([separator])
    def append_cell(self, cell_lines):
        """cell_lines is an array of lines"""
        start = 0
        if len(cell_lines) > 0 and cell_lines[0] == '.sp\n':
            start = 1
        self._rows[-1].append(cell_lines[start:])
        if len(self._coldefs) < len(self._rows[-1]):
            self._coldefs.append('l')
    def _minimize_cell(self, cell_lines):
        """Remove leading and trailing blank and ``.sp`` lines"""
        while (cell_lines and cell_lines[0] in ('\n', '.sp\n')):
            del cell_lines[0]
        while (cell_lines and cell_lines[-1] in ('\n', '.sp\n')):
            del cell_lines[-1]
    def as_list(self):
        text = ['.TS\n']
        text.append(' '.join(self._options) + ';\n')
        text.append('|%s|.\n' % ('|'.join(self._coldefs)))
        for row in self._rows:
            # row = array of cells. cell = array of lines.
            text.append('_\n')       # line above
            text.append('T{\n')
            for i in range(len(row)):
                cell = row[i]
                self._minimize_cell(cell)
                text.extend(cell)
                if not text[-1].endswith('\n'):
                    text[-1] += '\n'
                if i < len(row)-1:
                    text.append('T}'+self._tab_char+'T{\n')
                else:
                    text.append('T}\n')
        text.append('_\n')
        text.append('.TE\n')
        return text

class Translator(nodes.NodeVisitor):
    """"""

    words_and_spaces = re.compile(r'\S+| +|\n')
    document_start = """Man page generated from reStructeredText."""

    def __init__(self, document):
        nodes.NodeVisitor.__init__(self, document)
        self.settings = settings = document.settings
        lcode = settings.language_code
        arglen = len(inspect.getargspec(languages.get_language)[0])
        if arglen == 2:
            self.language = languages.get_language(lcode,
                                                   self.document.reporter)
        else:
            self.language = languages.get_language(lcode)
        self.head = []
        self.body = []
        self.foot = []
        self.section_level = 0
        self.context = []
        self.topic_class = ''
        self.colspecs = []
        self.compact_p = 1
        self.compact_simple = None
        # the list style "*" bullet or "#" numbered
        self._list_char = []
        # writing the header .TH and .SH NAME is postboned after
        # docinfo.
        self._docinfo = {
                "title" : "", "title_upper": "",
                "subtitle" : "",
                "manual_section" : "", "manual_group" : "",
                "author" : [],
                "date" : "",
                "copyright" : "",
                "version" : "",
                    }
        self._docinfo_keys = []     # a list to keep the sequence as in source.
        self._docinfo_names = {}    # to get name from text not normalized.
        self._in_docinfo = None
        self._active_table = None
        self._in_literal = False
        self.header_written = 0
        self._line_block = 0
        self.authors = []
        self.section_level = 0
        self._indent = [0]
        # central definition of simple processing rules
        # what to output on : visit, depart
        # Do not use paragraph requests ``.PP`` because these set indentation.
        # use ``.sp``. Remove superfluous ``.sp`` in ``astext``.
        #
        # Fonts are put on a stack, the top one is used.
        # ``.ft P`` or ``\\fP`` pop from stack.
        # ``B`` bold, ``I`` italic, ``R`` roman should be available.
        # Hopefully ``C`` courier too.
        self.defs = {
                'indent' : ('.INDENT %.1f\n', '.UNINDENT\n'),
                'definition_list_item' : ('.TP', ''),
                'field_name' : ('.TP\n.B ', '\n'),
                'literal' : ('\\fB', '\\fP'),
                'literal_block' : ('.sp\n.nf\n.ft C\n', '\n.ft P\n.fi\n'),

                'option_list_item' : ('.TP\n', ''),

                'reference' : (r'\%', r'\:'),
                'emphasis': ('\\fI', '\\fP'),
                'strong' : ('\\fB', '\\fP'),
                'term' : ('\n.B ', '\n'),
                'title_reference' : ('\\fI', '\\fP'),

                'topic-title' : ('.SS ',),
                'sidebar-title' : ('.SS ',),

                'problematic' : ('\n.nf\n', '\n.fi\n'),
                    }
        # NOTE don't specify the newline before a dot-command, but ensure
        # it is there.

    def comment_begin(self, text):
        """Return commented version of the passed text WITHOUT end of
        line/comment."""
        prefix = '.\\" '
        out_text = ''.join(
            [(prefix + in_line + '\n')
            for in_line in text.split('\n')])
        return out_text

    def comment(self, text):
        """Return commented version of the passed text."""
        return self.comment_begin(text)+'.\n'

    def ensure_eol(self):
        """Ensure the last line in body is terminated by new line."""
        if self.body[-1][-1] != '\n':
            self.body.append('\n')

    def astext(self):
        """Return the final formatted document as a string."""
        if not self.header_written:
            # ensure we get a ".TH" as viewers require it.
            self.head.append(self.header())
        # filter body
        for i in xrange(len(self.body)-1, 0, -1):
            # remove superfluous vertical gaps.
            if self.body[i] == '.sp\n':
                if self.body[i - 1][:4] in ('.BI ','.IP '):
                    self.body[i] = '.\n'
                elif (self.body[i - 1][:3] == '.B ' and
                    self.body[i - 2][:4] == '.TP\n'):
                    self.body[i] = '.\n'
                elif (self.body[i - 1] == '\n' and
                    self.body[i - 2][0] != '.' and
                    (self.body[i - 3][:7] == '.TP\n.B '
                        or self.body[i - 3][:4] == '\n.B ')
                     ):
                    self.body[i] = '.\n'
        return ''.join(self.head + self.body + self.foot)

    def deunicode(self, text):
        text = text.replace(u'\xa0', '\\ ')
        text = text.replace(u'\u2020', '\\(dg')
        return text

    def visit_Text(self, node):
        text = node.astext()
        text = text.replace('\\','\\e')
        replace_pairs = [
            (u'-', ur'\-'),
            (u'\'', ur'\(aq'),
            (u'´', ur'\''),
            (u'`', ur'\(ga'),
            ]
        for (in_char, out_markup) in replace_pairs:
            text = text.replace(in_char, out_markup)
        # unicode
        text = self.deunicode(text)
        if self._in_literal:
            # prevent interpretation of "." at line start
            if text[0] == '.':
                text = '\\&' + text
            text = text.replace('\n.', '\n\\&.')
        self.body.append(text)

    def depart_Text(self, node):
        pass

    def list_start(self, node):
        class enum_char(object):
            enum_style = {
                    'bullet'     : '\\(bu',
                    'emdash'     : '\\(em',
                     }

            def __init__(self, style):
                self._style = style
                if 'start' in node:
                    self._cnt = node['start'] - 1
                else:
                    self._cnt = 0
                self._indent = 2
                if style == 'arabic':
                    # indentation depends on number of childrens
                    # and start value.
                    self._indent = len(str(len(node.children)))
                    self._indent += len(str(self._cnt)) + 1
                elif style == 'loweralpha':
                    self._cnt += ord('a') - 1
                    self._indent = 3
                elif style == 'upperalpha':
                    self._cnt += ord('A') - 1
                    self._indent = 3
                elif style.endswith('roman'):
                    self._indent = 5

            def next(self):
                if self._style == 'bullet':
                    return self.enum_style[self._style]
                elif self._style == 'emdash':
                    return self.enum_style[self._style]
                self._cnt += 1
                # TODO add prefix postfix
                if self._style == 'arabic':
                    return "%d." % self._cnt
                elif self._style in ('loweralpha', 'upperalpha'):
                    return "%c." % self._cnt
                elif self._style.endswith('roman'):
                    res = roman.toRoman(self._cnt) + '.'
                    if self._style.startswith('upper'):
                        return res.upper()
                    return res.lower()
                else:
                    return "%d." % self._cnt
            def get_width(self):
                return self._indent
            def __repr__(self):
                return 'enum_style-%s' % list(self._style)

        if 'enumtype' in node:
            self._list_char.append(enum_char(node['enumtype']))
        else:
            self._list_char.append(enum_char('bullet'))
        if len(self._list_char) > 1:
            # indent nested lists
            self.indent(self._list_char[-2].get_width())
        else:
            self.indent(self._list_char[-1].get_width())

    def list_end(self):
        self.dedent()
        self._list_char.pop()

    def header(self):
        tmpl = (".TH %(title_upper)s %(manual_section)s"
                " \"%(date)s\" \"%(version)s\" \"%(manual_group)s\"\n"
                ".SH NAME\n"
                "%(title)s \- %(subtitle)s\n")
        return tmpl % self._docinfo

    def append_header(self):
        """append header with .TH and .SH NAME"""
        # NOTE before everything
        # .TH title_upper section date source manual
        if self.header_written:
            return
        self.body.append(self.header())
        self.body.append(MACRO_DEF)
        self.header_written = 1

    def visit_address(self, node):
        self.visit_docinfo_item(node, 'address')

    def depart_address(self, node):
        pass

    def visit_admonition(self, node, name=None):
        if name:
            self.body.append('.IP %s\n' %
                        self.language.labels.get(name, name))

    def depart_admonition(self, node):
        self.body.append('.RE\n')

    def visit_attention(self, node):
        self.visit_admonition(node, 'attention')

    depart_attention = depart_admonition

    def visit_docinfo_item(self, node, name):
        if name == 'author':
            self._docinfo[name].append(node.astext())
        else:
            self._docinfo[name] = node.astext()
        self._docinfo_keys.append(name)
        raise nodes.SkipNode

    def depart_docinfo_item(self, node):
        pass

    def visit_author(self, node):
        self.visit_docinfo_item(node, 'author')

    depart_author = depart_docinfo_item

    def visit_authors(self, node):
        # _author is called anyway.
        pass

    def depart_authors(self, node):
        pass

    def visit_block_quote(self, node):
        # BUG/HACK: indent alway uses the _last_ indention,
        # thus we need two of them.
        self.indent(BLOCKQOUTE_INDENT)
        self.indent(0)

    def depart_block_quote(self, node):
        self.dedent()
        self.dedent()

    def visit_bullet_list(self, node):
        self.list_start(node)

    def depart_bullet_list(self, node):
        self.list_end()

    def visit_caption(self, node):
        pass

    def depart_caption(self, node):
        pass

    def visit_caution(self, node):
        self.visit_admonition(node, 'caution')

    depart_caution = depart_admonition

    def visit_citation(self, node):
        num, text = node.astext().split(None, 1)
        num = num.strip()
        self.body.append('.IP [%s] 5\n' % num)

    def depart_citation(self, node):
        pass

    def visit_citation_reference(self, node):
        self.body.append('['+node.astext()+']')
        raise nodes.SkipNode

    def visit_classifier(self, node):
        pass

    def depart_classifier(self, node):
        pass

    def visit_colspec(self, node):
        self.colspecs.append(node)

    def depart_colspec(self, node):
        pass

    def write_colspecs(self):
        self.body.append("%s.\n" % ('L '*len(self.colspecs)))

    def visit_comment(self, node,
                      sub=re.compile('-(?=-)').sub):
        self.body.append(self.comment(node.astext()))
        raise nodes.SkipNode

    def visit_contact(self, node):
        self.visit_docinfo_item(node, 'contact')

    depart_contact = depart_docinfo_item

    def visit_container(self, node):
        pass

    def depart_container(self, node):
        pass

    def visit_compound(self, node):
        pass

    def depart_compound(self, node):
        pass

    def visit_copyright(self, node):
        self.visit_docinfo_item(node, 'copyright')

    def visit_danger(self, node):
        self.visit_admonition(node, 'danger')

    depart_danger = depart_admonition

    def visit_date(self, node):
        self.visit_docinfo_item(node, 'date')

    def visit_decoration(self, node):
        pass

    def depart_decoration(self, node):
        pass

    def visit_definition(self, node):
        pass

    def depart_definition(self, node):
        pass

    def visit_definition_list(self, node):
        self.indent(DEFINITION_LIST_INDENT)

    def depart_definition_list(self, node):
        self.dedent()

    def visit_definition_list_item(self, node):
        self.body.append(self.defs['definition_list_item'][0])

    def depart_definition_list_item(self, node):
        self.body.append(self.defs['definition_list_item'][1])

    def visit_description(self, node):
        pass

    def depart_description(self, node):
        pass

    def visit_docinfo(self, node):
        self._in_docinfo = 1

    def depart_docinfo(self, node):
        self._in_docinfo = None
        # NOTE nothing should be written before this
        self.append_header()

    def visit_doctest_block(self, node):
        self.body.append(self.defs['literal_block'][0])
        self._in_literal = True

    def depart_doctest_block(self, node):
        self._in_literal = False
        self.body.append(self.defs['literal_block'][1])

    def visit_document(self, node):
        # no blank line between comment and header.
        self.body.append(self.comment(self.document_start).rstrip()+'\n')
        # writing header is postboned
        self.header_written = 0

    def depart_document(self, node):
        if self._docinfo['author']:
            self.body.append('.SH AUTHOR\n%s\n'
                    % ', '.join(self._docinfo['author']))
        skip = ('author', 'copyright', 'date',
                'manual_group', 'manual_section',
                'subtitle',
                'title', 'title_upper', 'version')
        for name in self._docinfo_keys:
            if name == 'address':
                self.body.append("\n%s:\n%s%s.nf\n%s\n.fi\n%s%s" % (
                                    self.language.labels.get(name, name),
                                    self.defs['indent'][0] % 0,
                                    self.defs['indent'][0] % BLOCKQOUTE_INDENT,
                                    self._docinfo[name],
                                    self.defs['indent'][1],
                                    self.defs['indent'][1]))
            elif not name in skip:
                if name in self._docinfo_names:
                    label = self._docinfo_names[name]
                else:
                    label = self.language.labels.get(name, name)
                self.body.append("\n%s: %s\n" % (label, self._docinfo[name]))
        if self._docinfo['copyright']:
            self.body.append('.SH COPYRIGHT\n%s\n'
                    % self._docinfo['copyright'])
        self.body.append(self.comment(
                        'Generated by docutils manpage writer.\n'))

    def visit_emphasis(self, node):
        self.body.append(self.defs['emphasis'][0])

    def depart_emphasis(self, node):
        self.body.append(self.defs['emphasis'][1])

    def visit_entry(self, node):
        # a cell in a table row
        if 'morerows' in node:
            self.document.reporter.warning('"table row spanning" not supported',
                    base_node=node)
        if 'morecols' in node:
            self.document.reporter.warning(
                    '"table cell spanning" not supported', base_node=node)
        self.context.append(len(self.body))

    def depart_entry(self, node):
        start = self.context.pop()
        self._active_table.append_cell(self.body[start:])
        del self.body[start:]

    def visit_enumerated_list(self, node):
        self.list_start(node)

    def depart_enumerated_list(self, node):
        self.list_end()

    def visit_error(self, node):
        self.visit_admonition(node, 'error')

    depart_error = depart_admonition

    def visit_field(self, node):
        pass

    def depart_field(self, node):
        pass

    def visit_field_body(self, node):
        if self._in_docinfo:
            name_normalized = self._field_name.lower().replace(" ","_")
            self._docinfo_names[name_normalized] = self._field_name
            self.visit_docinfo_item(node, name_normalized)
            raise nodes.SkipNode

    def depart_field_body(self, node):
        pass

    def visit_field_list(self, node):
        self.indent(FIELD_LIST_INDENT)

    def depart_field_list(self, node):
        self.dedent()

    def visit_field_name(self, node):
        if self._in_docinfo:
            self._field_name = node.astext()
            raise nodes.SkipNode
        else:
            self.body.append(self.defs['field_name'][0])

    def depart_field_name(self, node):
        self.body.append(self.defs['field_name'][1])

    def visit_figure(self, node):
        self.indent(2.5)
        self.indent(0)

    def depart_figure(self, node):
        self.dedent()
        self.dedent()

    def visit_footer(self, node):
        self.document.reporter.warning('"footer" not supported',
                base_node=node)

    def depart_footer(self, node):
        pass

    def visit_footnote(self, node):
        num, text = node.astext().split(None, 1)
        num = num.strip()
        self.body.append('.IP [%s] 5\n' % self.deunicode(num))

    def depart_footnote(self, node):
        pass

    def footnote_backrefs(self, node):
        self.document.reporter.warning('"footnote_backrefs" not supported',
                base_node=node)

    def visit_footnote_reference(self, node):
        self.body.append('['+self.deunicode(node.astext())+']')
        raise nodes.SkipNode

    def depart_footnote_reference(self, node):
        pass

    def visit_generated(self, node):
        pass

    def depart_generated(self, node):
        pass

    def visit_header(self, node):
        raise NotImplementedError, node.astext()

    def depart_header(self, node):
        pass

    def visit_hint(self, node):
        self.visit_admonition(node, 'hint')

    depart_hint = depart_admonition

    def visit_subscript(self, node):
        self.body.append('\\s-2\\d')

    def depart_subscript(self, node):
        self.body.append('\\u\\s0')

    def visit_superscript(self, node):
        self.body.append('\\s-2\\u')

    def depart_superscript(self, node):
        self.body.append('\\d\\s0')

    def visit_attribution(self, node):
        self.body.append('\\(em ')

    def depart_attribution(self, node):
        self.body.append('\n')

    def visit_image(self, node):
        self.document.reporter.warning('"image" not supported',
                base_node=node)
        text = []
        if 'alt' in node.attributes:
            text.append(node.attributes['alt'])
        if 'uri' in node.attributes:
            text.append(node.attributes['uri'])
        self.body.append('[image: %s]\n' % ('/'.join(text)))
        raise nodes.SkipNode

    def visit_important(self, node):
        self.visit_admonition(node, 'important')

    depart_important = depart_admonition

    def visit_label(self, node):
        # footnote and citation
        if (isinstance(node.parent, nodes.footnote)
            or isinstance(node.parent, nodes.citation)):
            raise nodes.SkipNode
        self.document.reporter.warning('"unsupported "label"',
                base_node=node)
        self.body.append('[')

    def depart_label(self, node):
        self.body.append(']\n')

    def visit_legend(self, node):
        pass

    def depart_legend(self, node):
        pass

    # WHAT should we use .INDENT, .UNINDENT ?
    def visit_line_block(self, node):
        self._line_block += 1
        if self._line_block == 1:
            self.body.append('.sp\n')
            self.body.append('.nf\n')
        else:
            self.body.append('.in +2\n')

    def depart_line_block(self, node):
        self._line_block -= 1
        if self._line_block == 0:
            self.body.append('.fi\n')
            self.body.append('.sp\n')
        else:
            self.body.append('.in -2\n')

    def visit_line(self, node):
        pass

    def depart_line(self, node):
        self.body.append('\n')

    def visit_list_item(self, node):
        # man 7 man argues to use ".IP" instead of ".TP"
        self.body.append('.IP %s %d\n' % (
                self._list_char[-1].next(),
                self._list_char[-1].get_width(),))

    def depart_list_item(self, node):
        pass

    def visit_literal(self, node):
        self.body.append(self.defs['literal'][0])

    def depart_literal(self, node):
        self.body.append(self.defs['literal'][1])

    def visit_literal_block(self, node):
        self.body.append(self.defs['literal_block'][0])
        self._in_literal = True

    def depart_literal_block(self, node):
        self._in_literal = False
        self.body.append(self.defs['literal_block'][1])

    def visit_meta(self, node):
        raise NotImplementedError, node.astext()

    def depart_meta(self, node):
        pass

    def visit_note(self, node):
        self.visit_admonition(node, 'note')

    depart_note = depart_admonition

    def indent(self, by=0.5):
        # if we are in a section ".SH" there already is a .RS
        step = self._indent[-1]
        self._indent.append(by)
        self.body.append(self.defs['indent'][0] % step)

    def dedent(self):
        self._indent.pop()
        self.body.append(self.defs['indent'][1])

    def visit_option_list(self, node):
        self.indent(OPTION_LIST_INDENT)

    def depart_option_list(self, node):
        self.dedent()

    def visit_option_list_item(self, node):
        # one item of the list
        self.body.append(self.defs['option_list_item'][0])

    def depart_option_list_item(self, node):
        self.body.append(self.defs['option_list_item'][1])

    def visit_option_group(self, node):
        # as one option could have several forms it is a group
        # options without parameter bold only, .B, -v
        # options with parameter bold italic, .BI, -f file
        #
        # we do not know if .B or .BI
        self.context.append('.B')           # blind guess
        self.context.append(len(self.body)) # to be able to insert later
        self.context.append(0)              # option counter

    def depart_option_group(self, node):
        self.context.pop()  # the counter
        start_position = self.context.pop()
        text = self.body[start_position:]
        del self.body[start_position:]
        self.body.append('%s%s\n' % (self.context.pop(), ''.join(text)))

    def visit_option(self, node):
        # each form of the option will be presented separately
        if self.context[-1] > 0:
            self.body.append(', ')
        if self.context[-3] == '.BI':
            self.body.append('\\')
        self.body.append(' ')

    def depart_option(self, node):
        self.context[-1] += 1

    def visit_option_string(self, node):
        # do not know if .B or .BI
        pass

    def depart_option_string(self, node):
        pass

    def visit_option_argument(self, node):
        self.context[-3] = '.BI' # bold/italic alternate
        if node['delimiter'] != ' ':
            self.body.append('\\fB%s ' % node['delimiter'])
        elif self.body[len(self.body)-1].endswith('='):
            # a blank only means no blank in output, just changing font
            self.body.append(' ')
        else:
            # blank backslash blank, switch font then a blank
            self.body.append(' \\ ')

    def depart_option_argument(self, node):
        pass

    def visit_organization(self, node):
        self.visit_docinfo_item(node, 'organization')

    def depart_organization(self, node):
        pass

    def visit_paragraph(self, node):
        # ``.PP`` : Start standard indented paragraph.
        # ``.LP`` : Start block paragraph, all except the first.
        # ``.P [type]``  : Start paragraph type.
        # NOTE dont use paragraph starts because they reset indentation.
        # ``.sp`` is only vertical space
        self.ensure_eol()
        self.body.append('.sp\n')

    def depart_paragraph(self, node):
        self.body.append('\n')

    def visit_problematic(self, node):
        self.body.append(self.defs['problematic'][0])

    def depart_problematic(self, node):
        self.body.append(self.defs['problematic'][1])

    def visit_raw(self, node):
        if node.get('format') == 'manpage':
            self.body.append(node.astext() + "\n")
        # Keep non-manpage raw text out of output:
        raise nodes.SkipNode

    def visit_reference(self, node):
        """E.g. link or email address."""
        self.body.append(self.defs['reference'][0])

    def depart_reference(self, node):
        self.body.append(self.defs['reference'][1])

    def visit_revision(self, node):
        self.visit_docinfo_item(node, 'revision')

    depart_revision = depart_docinfo_item

    def visit_row(self, node):
        self._active_table.new_row()

    def depart_row(self, node):
        pass

    def visit_section(self, node):
        self.section_level += 1

    def depart_section(self, node):
        self.section_level -= 1

    def visit_status(self, node):
        self.visit_docinfo_item(node, 'status')

    depart_status = depart_docinfo_item

    def visit_strong(self, node):
        self.body.append(self.defs['strong'][0])

    def depart_strong(self, node):
        self.body.append(self.defs['strong'][1])

    def visit_substitution_definition(self, node):
        """Internal only."""
        raise nodes.SkipNode

    def visit_substitution_reference(self, node):
        self.document.reporter.warning('"substitution_reference" not supported',
                base_node=node)

    def visit_subtitle(self, node):
        if isinstance(node.parent, nodes.sidebar):
            self.body.append(self.defs['strong'][0])
        elif isinstance(node.parent, nodes.document):
            self.visit_docinfo_item(node, 'subtitle')
        elif isinstance(node.parent, nodes.section):
            self.body.append(self.defs['strong'][0])

    def depart_subtitle(self, node):
        # document subtitle calls SkipNode
        self.body.append(self.defs['strong'][1]+'\n.PP\n')

    def visit_system_message(self, node):
        # TODO add report_level
        #if node['level'] < self.document.reporter['writer'].report_level:
        #    Level is too low to display:
        #    raise nodes.SkipNode
        attr = {}
        backref_text = ''
        if node.hasattr('id'):
            attr['name'] = node['id']
        if node.hasattr('line'):
            line = ', line %s' % node['line']
        else:
            line = ''
        self.body.append('.IP "System Message: %s/%s (%s:%s)"\n'
                         % (node['type'], node['level'], node['source'], line))

    def depart_system_message(self, node):
        pass

    def visit_table(self, node):
        self._active_table = Table()

    def depart_table(self, node):
        self.ensure_eol()
        self.body.extend(self._active_table.as_list())
        self._active_table = None

    def visit_target(self, node):
        # targets are in-document hyper targets, without any use for man-pages.
        raise nodes.SkipNode

    def visit_tbody(self, node):
        pass

    def depart_tbody(self, node):
        pass

    def visit_term(self, node):
        self.body.append(self.defs['term'][0])

    def depart_term(self, node):
        self.body.append(self.defs['term'][1])

    def visit_tgroup(self, node):
        pass

    def depart_tgroup(self, node):
        pass

    def visit_thead(self, node):
        # MAYBE double line '='
        pass

    def depart_thead(self, node):
        # MAYBE double line '='
        pass

    def visit_tip(self, node):
        self.visit_admonition(node, 'tip')

    depart_tip = depart_admonition

    def visit_title(self, node):
        if isinstance(node.parent, nodes.topic):
            self.body.append(self.defs['topic-title'][0])
        elif isinstance(node.parent, nodes.sidebar):
            self.body.append(self.defs['sidebar-title'][0])
        elif isinstance(node.parent, nodes.admonition):
            self.body.append('.IP "')
        elif self.section_level == 0:
            self._docinfo['title'] = node.astext()
            # document title for .TH
            self._docinfo['title_upper'] = node.astext().upper()
            raise nodes.SkipNode
        elif self.section_level == 1:
            self.body.append('.SH ')
            for n in node.traverse(nodes.Text):
                n.parent.replace(n, nodes.Text(n.astext().upper()))
        else:
            self.body.append('.SS ')

    def depart_title(self, node):
        if isinstance(node.parent, nodes.admonition):
            self.body.append('"')
        self.body.append('\n')

    def visit_title_reference(self, node):
        """inline citation reference"""
        self.body.append(self.defs['title_reference'][0])

    def depart_title_reference(self, node):
        self.body.append(self.defs['title_reference'][1])

    def visit_topic(self, node):
        pass

    def depart_topic(self, node):
        pass

    def visit_sidebar(self, node):
        pass

    def depart_sidebar(self, node):
        pass

    def visit_rubric(self, node):
        pass

    def depart_rubric(self, node):
        pass

    def visit_transition(self, node):
        # .PP      Begin a new paragraph and reset prevailing indent.
        # .sp N    leaves N lines of blank space.
        # .ce      centers the next line
        self.body.append('\n.sp\n.ce\n----\n')

    def depart_transition(self, node):
        self.body.append('\n.ce 0\n.sp\n')

    def visit_version(self, node):
        self.visit_docinfo_item(node, 'version')

    def visit_warning(self, node):
        self.visit_admonition(node, 'warning')

    depart_warning = depart_admonition

    def unimplemented_visit(self, node):
        raise NotImplementedError('visiting unimplemented node type: %s'
                                  % node.__class__.__name__)

# vim: set fileencoding=utf-8 et ts=4 ai :