view doc/hgmanpage.py @ 42044:bb271ec2fbfb

compression: introduce a `storage.revlog.zstd.level` configuration This option control the zstd compression level used when compressing revlog chunk. The usage of zstd for revlog compression has not graduated from experimental yet, but we intend to fix that soon. The option name for the compression level is more straight forward to pick, so this changesets comes first. Having a dedicated option for each compression engine is useful because they don't support the same range of values. I ran the same measurement as for the zlib compression level (in the parent changesets). The variation in repository size is stay mostly in the same (small) range. The "read/write" performance see smallish variation, but are overall much better than zlib. Write performance show the same tend of having better write performance for when reaching high-end compression. Again, we don't intend to change the default zstd compression level (currently: 3) in this series. However this is worth investigating in the future. The Performance comparison of zlib vs zstd is quite impressive. The repository size stay in the same range, but the performance are much better in all situations. Comparison summary ================== We are looking at: - performance range for zlib - performance range for zstd - comparison of default zstd (level-3) to default zlib (level 6) - comparison of the slowest zstd time to the fastest zlib time Read performance: ----------------- | zlib | zstd | cmp | f2s mercurial | 0.170159 - 0.189219 | 0.144127 - 0.149624 | 80% | 88% pypy | 2.679217 - 2.768691 | 1.532317 - 1.705044 | 60% | 63% netbeans | 122.477027 - 141.620281 | 72.996346 - 89.731560 | 58% | 73% mozilla | 147.867662 - 170.572118 | 91.700995 - 105.853099 | 56% | 71% Write performance: ------------------ | zlib | zstd | cmp | f2s mercurial | 53.250304 - 56.2936129 | 40.877025 - 45.677286 | 75% | 86% pypy | 460.721984 - 476.589918 | 270.545409 - 301.002219 | 63% | 65% netbeans | 520.560316 - 715.930400 | 370.356311 - 428.329652 | 55% | 82% mozilla | 739.803002 - 987.056093 | 505.152906 - 591.930683 | 57% | 80% Raw data -------- repo alg lvl .hg/store size 00manifest.d read write mercurial zlib 1 49,402,813 5,963,475 0.170159 53.250304 mercurial zlib 6 47,197,397 5,875,730 0.182820 56.264320 mercurial zlib 9 47,121,596 5,849,781 0.189219 56.293612 mercurial zstd 1 49,737,084 5,966,355 0.144127 40.877025 mercurial zstd 3 48,961,867 5,895,208 0.146376 42.268142 mercurial zstd 5 48,200,592 5,938,676 0.149624 43.162875 mercurial zstd 10 47,833,520 5,913,353 0.145185 44.012489 mercurial zstd 15 47,314,604 5,728,679 0.147686 45.677286 mercurial zstd 20 47,330,502 5,830,539 0.145789 45.025407 mercurial zstd 22 47,330,076 5,830,539 0.143996 44.690460 pypy zlib 1 370,830,572 28,462,425 2.679217 460.721984 pypy zlib 6 340,112,317 27,648,747 2.768691 467.537158 pypy zlib 9 338,360,736 27,639,003 2.763495 476.589918 pypy zstd 1 362,377,479 27,916,214 1.532317 270.545409 pypy zstd 3 354,137,693 27,905,988 1.686718 294.951509 pypy zstd 5 342,640,043 27,655,774 1.705044 301.002219 pypy zstd 10 334,224,327 27,164,493 1.567287 285.186239 pypy zstd 15 329,000,363 26,645,965 1.637729 299.561332 pypy zstd 20 324,534,039 26,199,547 1.526813 302.149827 pypy zstd 22 324,530,595 26,198,932 1.525718 307.821218 netbeans zlib 1 1,281,847,810 165,495,457 122.477027 520.560316 netbeans zlib 6 1,205,284,353 159,161,207 139.876147 715.930400 netbeans zlib 9 1,197,135,671 155,034,586 141.620281 678.297064 netbeans zstd 1 1,259,581,737 160,840,613 72.996346 370.356311 netbeans zstd 3 1,232,978,122 157,691,551 81.622317 396.733087 netbeans zstd 5 1,208,034,075 160,246,880 83.080549 364.342626 netbeans zstd 10 1,188,624,176 156,083,417 79.323935 403.594602 netbeans zstd 15 1,176,973,589 153,859,477 89.731560 428.329652 netbeans zstd 20 1,162,958,258 151,147,535 82.842667 392.335349 netbeans zstd 22 1,162,707,029 151,150,220 82.565695 402.840655 mozilla zlib 1 2,775,497,186 298,527,987 147.867662 751.263721 mozilla zlib 6 2,596,856,420 286,597,671 170.572118 987.056093 mozilla zlib 9 2,587,542,494 287,018,264 163.622338 739.803002 mozilla zstd 1 2,723,159,348 286,617,532 91.700995 570.042751 mozilla zstd 3 2,665,055,001 286,152,013 95.240155 561.412805 mozilla zstd 5 2,607,819,817 288,060,030 101.978048 505.152906 mozilla zstd 10 2,558,761,085 283,967,648 104.113481 497.771202 mozilla zstd 15 2,526,216,060 275,581,300 105.853099 591.930683 mozilla zstd 20 2,485,114,806 266,478,859 95.268795 576.515389 mozilla zstd 22 2,484,869,080 266,456,505 94.429282 572.785537
author Pierre-Yves David <pierre-yves.david@octobus.net>
date Wed, 27 Mar 2019 18:35:59 +0100
parents eb14ab7db33e
children 51df72655b1a
line wrap: on
line source

# -*- coding: utf-8 -*-
# $Id: manpage.py 6110 2009-08-31 14:40:33Z grubert $
# Author: Engelbert Gruber <grubert@users.sourceforge.net>
# 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 in *troff*, a text file formatting system.

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

Man pages have no subsections 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.

"""
from __future__ import absolute_import

__docformat__ = 'reStructuredText'

import inspect
import re

from docutils import (
    languages,
    nodes,
    writers,
)
try:
    import roman
except ImportError:
    from docutils.utils import roman

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 reStructuredText."""

    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'-', u'\\-'),
            (u"'", u'\\(aq'),
            (u'ยด', u"\\'"),
            (u'`', u'\\(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 children
                    # 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 always uses the _last_ indentation,
        # 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 name not 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' % (
                next(self._list_char[-1]),
                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 don't 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 = {}
        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 :