aboutsummaryrefslogtreecommitdiffstats
path: root/meta/classes/externalsrc.bbclass
blob: da7eb4781c51a4a0cf44ef5f7c30777971fcb0ac (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
# Copyright (C) 2012 Linux Foundation
# Author: Richard Purdie
# Some code and influence taken from srctree.bbclass:
# Copyright (C) 2009 Chris Larson <clarson@kergoth.com>
# Released under the MIT license (see COPYING.MIT for the terms)
#
# externalsrc.bbclass enables use of an existing source tree, usually external to 
# the build system to build a piece of software rather than the usual fetch/unpack/patch
# process.
#
# To use, add externalsrc to the global inherit and set EXTERNALSRC to point at the
# directory you want to use containing the sources e.g. from local.conf for a recipe
# called "myrecipe" you would do:
#
# INHERIT += "externalsrc"
# EXTERNALSRC_pn-myrecipe = "/path/to/my/source/tree"
#
# In order to make this class work for both target and native versions (or with
# multilibs/cross or other BBCLASSEXTEND variants), B is set to point to a separate
# directory under the work directory (split source and build directories). This is
# the default, but the build directory can be set to the source directory if
# circumstances dictate by setting EXTERNALSRC_BUILD to the same value, e.g.:
#
# EXTERNALSRC_BUILD_pn-myrecipe = "/path/to/my/source/tree"
#

SRCTREECOVEREDTASKS ?= "do_patch do_unpack do_fetch"
EXTERNALSRC_SYMLINKS ?= "oe-workdir:${WORKDIR} oe-logs:${T}"

python () {
    externalsrc = d.getVar('EXTERNALSRC', True)
    if externalsrc:
        d.setVar('S', externalsrc)
        externalsrcbuild = d.getVar('EXTERNALSRC_BUILD', True)
        if externalsrcbuild:
            d.setVar('B', externalsrcbuild)
        else:
            d.setVar('B', '${WORKDIR}/${BPN}-${PV}/')

        local_srcuri = []
        fetch = bb.fetch2.Fetch((d.getVar('SRC_URI', True) or '').split(), d)
        for url in fetch.urls:
            url_data = fetch.ud[url]
            parm = url_data.parm
            if (url_data.type == 'file' or
                    'type' in parm and parm['type'] == 'kmeta'):
                local_srcuri.append(url)

        d.setVar('SRC_URI', ' '.join(local_srcuri))

        if '{SRCPV}' in d.getVar('PV', False):
            # Dummy value because the default function can't be called with blank SRC_URI
            d.setVar('SRCPV', '999')

        tasks = filter(lambda k: d.getVarFlag(k, "task", True), d.keys())

        for task in tasks:
            if task.endswith("_setscene"):
                # sstate is never going to work for external source trees, disable it
                bb.build.deltask(task, d)
            else:
                # Since configure will likely touch ${S}, ensure only we lock so one task has access at a time
                d.appendVarFlag(task, "lockfiles", " ${S}/singletask.lock")

            # We do not want our source to be wiped out, ever (kernel.bbclass does this for do_clean)
            cleandirs = (d.getVarFlag(task, 'cleandirs', False) or '').split()
            setvalue = False
            for cleandir in cleandirs[:]:
                if d.expand(cleandir) == externalsrc:
                    cleandirs.remove(cleandir)
                    setvalue = True
            if setvalue:
                d.setVarFlag(task, 'cleandirs', ' '.join(cleandirs))

        fetch_tasks = ['do_fetch', 'do_unpack']
        # If we deltask do_patch, there's no dependency to ensure do_unpack gets run, so add one
        # Note that we cannot use d.appendVarFlag() here because deps is expected to be a list object, not a string
        d.setVarFlag('do_configure', 'deps', (d.getVarFlag('do_configure', 'deps', False) or []) + ['do_unpack'])

        for task in d.getVar("SRCTREECOVEREDTASKS", True).split():
            if local_srcuri and task in fetch_tasks:
                continue
            bb.build.deltask(task, d)

        d.prependVarFlag('do_compile', 'prefuncs', "externalsrc_compile_prefunc ")
        d.prependVarFlag('do_configure', 'prefuncs', "externalsrc_configure_prefunc ")

        # Force the recipe to be always re-parsed so that the file_checksums
        # function is run every time
        d.setVar('BB_DONT_CACHE', '1')
        d.setVarFlag('do_compile', 'file-checksums', '${@srctree_hash_files(d)}')

        # We don't want the workdir to go away
        d.appendVar('RM_WORK_EXCLUDE', ' ' + d.getVar('PN', True))

        # If B=S the same builddir is used even for different architectures.
        # Thus, use a shared CONFIGURESTAMPFILE and STAMP directory so that
        # change of do_configure task hash is correctly detected and stamps are
        # invalidated if e.g. MACHINE changes.
        if d.getVar('S', True) == d.getVar('B', True):
            configstamp = '${TMPDIR}/work-shared/${PN}/${EXTENDPE}${PV}-${PR}/configure.sstate'
            d.setVar('CONFIGURESTAMPFILE', configstamp)
            d.setVar('STAMP', '${STAMPS_DIR}/work-shared/${PN}/${EXTENDPE}${PV}-${PR}')
}

python externalsrc_configure_prefunc() {
    # Create desired symlinks
    symlinks = (d.getVar('EXTERNALSRC_SYMLINKS', True) or '').split()
    for symlink in symlinks:
        symsplit = symlink.split(':', 1)
        lnkfile = os.path.join(d.getVar('S', True), symsplit[0])
        target = d.expand(symsplit[1])
        if len(symsplit) > 1:
            if os.path.islink(lnkfile):
                # Link already exists, leave it if it points to the right location already
                if os.readlink(lnkfile) == target:
                    continue
                os.unlink(lnkfile)
            elif os.path.exists(lnkfile):
                # File/dir exists with same name as link, just leave it alone
                continue
            os.symlink(target, lnkfile)
}

python externalsrc_compile_prefunc() {
    # Make it obvious that this is happening, since forgetting about it could lead to much confusion
    bb.plain('NOTE: %s: compiling from external source tree %s' % (d.getVar('PN', True), d.getVar('EXTERNALSRC', True)))
}

def srctree_hash_files(d):
    import shutil
    import subprocess
    import tempfile

    s_dir = d.getVar('EXTERNALSRC', True)
    git_dir = os.path.join(s_dir, '.git')
    oe_hash_file = os.path.join(git_dir, 'oe-devtool-tree-sha1')

    ret = " "
    if os.path.exists(git_dir):
        with tempfile.NamedTemporaryFile(dir=git_dir, prefix='oe-devtool-index') as tmp_index:
            # Clone index
            shutil.copy2(os.path.join(git_dir, 'index'), tmp_index.name)
            # Update our custom index
            env = os.environ.copy()
            env['GIT_INDEX_FILE'] = tmp_index.name
            subprocess.check_output(['git', 'add', '.'], cwd=s_dir, env=env)
            sha1 = subprocess.check_output(['git', 'write-tree'], cwd=s_dir, env=env)
        with open(oe_hash_file, 'w') as fobj:
            fobj.write(sha1)
        ret = oe_hash_file + ':True'
    else:
        ret = d.getVar('EXTERNALSRC', True) + '/*:True'
    return ret
ouble */ .highlight .se { color: #ae81ff } /* Literal.String.Escape */ .highlight .sh { color: #e6db74 } /* Literal.String.Heredoc */ .highlight .si { color: #e6db74 } /* Literal.String.Interpol */ .highlight .sx { color: #e6db74 } /* Literal.String.Other */ .highlight .sr { color: #e6db74 } /* Literal.String.Regex */ .highlight .s1 { color: #e6db74 } /* Literal.String.Single */ .highlight .ss { color: #e6db74 } /* Literal.String.Symbol */ .highlight .bp { color: #f8f8f2 } /* Name.Builtin.Pseudo */ .highlight .fm { color: #a6e22e } /* Name.Function.Magic */ .highlight .vc { color: #f8f8f2 } /* Name.Variable.Class */ .highlight .vg { color: #f8f8f2 } /* Name.Variable.Global */ .highlight .vi { color: #f8f8f2 } /* Name.Variable.Instance */ .highlight .vm { color: #f8f8f2 } /* Name.Variable.Magic */ .highlight .il { color: #ae81ff } /* Literal.Number.Integer.Long */ } @media (prefers-color-scheme: light) { .highlight .hll { background-color: #ffffcc } .highlight .c { color: #888888 } /* Comment */ .highlight .err { color: #a61717; background-color: #e3d2d2 } /* Error */ .highlight .k { color: #008800; font-weight: bold } /* Keyword */ .highlight .ch { color: #888888 } /* Comment.Hashbang */ .highlight .cm { color: #888888 } /* Comment.Multiline */ .highlight .cp { color: #cc0000; font-weight: bold } /* Comment.Preproc */ .highlight .cpf { color: #888888 } /* Comment.PreprocFile */ .highlight .c1 { color: #888888 } /* Comment.Single */ .highlight .cs { color: #cc0000; font-weight: bold; background-color: #fff0f0 } /* Comment.Special */ .highlight .gd { color: #000000; background-color: #ffdddd } /* Generic.Deleted */ .highlight .ge { font-style: italic } /* Generic.Emph */ .highlight .gr { color: #aa0000 } /* Generic.Error */ .highlight .gh { color: #333333 } /* Generic.Heading */ .highlight .gi { color: #000000; background-color: #ddffdd } /* Generic.Inserted */ .highlight .go { color: #888888 } /* Generic.Output */ .highlight .gp { color: #555555 } /* Generic.Prompt */ .highlight .gs { font-weight: bold } /* Generic.Strong */ .highlight .gu { color: #666666 } /* Generic.Subheading */ .highlight .gt { color: #aa0000 } /* Generic.Traceback */ .highlight .kc { color: #008800; font-weight: bold } /* Keyword.Constant */ .highlight .kd { color: #008800; font-weight: bold } /* Keyword.Declaration */ .highlight .kn { color: #008800; font-weight: bold } /* Keyword.Namespace */ .highlight .kp { color: #008800 } /* Keyword.Pseudo */ .highlight .kr { color: #008800; font-weight: bold } /* Keyword.Reserved */ .highlight .kt { color: #888888; font-weight: bold } /* Keyword.Type */ .highlight .m { color: #0000DD; font-weight: bold } /* Literal.Number */ .highlight .s { color: #dd2200; background-color: #fff0f0 } /* Literal.String */ .highlight .na { color: #336699 } /* Name.Attribute */ .highlight .nb { color: #003388 } /* Name.Builtin */ .highlight .nc { color: #bb0066; font-weight: bold } /* Name.Class */ .highlight .no { color: #003366; font-weight: bold } /* Name.Constant */ .highlight .nd { color: #555555 } /* Name.Decorator */ .highlight .ne { color: #bb0066; font-weight: bold } /* Name.Exception */ .highlight .nf { color: #0066bb; font-weight: bold } /* Name.Function */ .highlight .nl { color: #336699; font-style: italic } /* Name.Label */ .highlight .nn { color: #bb0066; font-weight: bold } /* Name.Namespace */ .highlight .py { color: #336699; font-weight: bold } /* Name.Property */ .highlight .nt { color: #bb0066; font-weight: bold } /* Name.Tag */ .highlight .nv { color: #336699 } /* Name.Variable */ .highlight .ow { color: #008800 } /* Operator.Word */ .highlight .w { color: #bbbbbb } /* Text.Whitespace */ .highlight .mb { color: #0000DD; font-weight: bold } /* Literal.Number.Bin */ .highlight .mf { color: #0000DD; font-weight: bold } /* Literal.Number.Float */ .highlight .mh { color: #0000DD; font-weight: bold } /* Literal.Number.Hex */ .highlight .mi { color: #0000DD; font-weight: bold } /* Literal.Number.Integer */ .highlight .mo { color: #0000DD; font-weight: bold } /* Literal.Number.Oct */ .highlight .sa { color: #dd2200; background-color: #fff0f0 } /* Literal.String.Affix */ .highlight .sb { color: #dd2200; background-color: #fff0f0 } /* Literal.String.Backtick */ .highlight .sc { color: #dd2200; background-color: #fff0f0 } /* Literal.String.Char */ .highlight .dl { color: #dd2200; background-color: #fff0f0 } /* Literal.String.Delimiter */ .highlight .sd { color: #dd2200; background-color: #fff0f0 } /* Literal.String.Doc */ .highlight .s2 { color: #dd2200; background-color: #fff0f0 } /* Literal.String.Double */ .highlight .se { color: #0044dd; background-color: #fff0f0 } /* Literal.String.Escape */ .highlight .sh { color: #dd2200; background-color: #fff0f0 } /* Literal.String.Heredoc */ .highlight .si { color: #3333bb; background-color: #fff0f0 } /* Literal.String.Interpol */ .highlight .sx { color: #22bb22; background-color: #f0fff0 } /* Literal.String.Other */ .highlight .sr { color: #008800; background-color: #fff0ff } /* Literal.String.Regex */ .highlight .s1 { color: #dd2200; background-color: #fff0f0 } /* Literal.String.Single */ .highlight .ss { color: #aa6600; background-color: #fff0f0 } /* Literal.String.Symbol */ .highlight .bp { color: #003388 } /* Name.Builtin.Pseudo */ .highlight .fm { color: #0066bb; font-weight: bold } /* Name.Function.Magic */ .highlight .vc { color: #336699 } /* Name.Variable.Class */ .highlight .vg { color: #dd7700 } /* Name.Variable.Global */ .highlight .vi { color: #3333bb } /* Name.Variable.Instance */ .highlight .vm { color: #336699 } /* Name.Variable.Magic */ .highlight .il { color: #0000DD; font-weight: bold } /* Literal.Number.Integer.Long */ }
# -*- coding: utf-8 -*-
"""
    codegen
    ~~~~~~~

    Extension to ast that allow ast -> python code generation.

    :copyright: Copyright 2008 by Armin Ronacher.
    :license: BSD.
"""
from ast import *

BOOLOP_SYMBOLS = {
    And:        'and',
    Or:         'or'
}

BINOP_SYMBOLS = {
    Add:        '+',
    Sub:        '-',
    Mult:       '*',
    Div:        '/',
    FloorDiv:   '//',
    Mod:        '%',
    LShift:     '<<',
    RShift:     '>>',
    BitOr:      '|',
    BitAnd:     '&',
    BitXor:     '^'
}

CMPOP_SYMBOLS = {
    Eq:         '==',
    Gt:         '>',
    GtE:        '>=',
    In:         'in',
    Is:         'is',
    IsNot:      'is not',
    Lt:         '<',
    LtE:        '<=',
    NotEq:      '!=',
    NotIn:      'not in'
}

UNARYOP_SYMBOLS = {
    Invert:     '~',
    Not:        'not',
    UAdd:       '+',
    USub:       '-'
}

ALL_SYMBOLS = {}
ALL_SYMBOLS.update(BOOLOP_SYMBOLS)
ALL_SYMBOLS.update(BINOP_SYMBOLS)
ALL_SYMBOLS.update(CMPOP_SYMBOLS)
ALL_SYMBOLS.update(UNARYOP_SYMBOLS)

def to_source(node, indent_with=' ' * 4, add_line_information=False):
    """This function can convert a node tree back into python sourcecode.
    This is useful for debugging purposes, especially if you're dealing with
    custom asts not generated by python itself.

    It could be that the sourcecode is evaluable when the AST itself is not
    compilable / evaluable.  The reason for this is that the AST contains some
    more data than regular sourcecode does, which is dropped during
    conversion.

    Each level of indentation is replaced with `indent_with`.  Per default this
    parameter is equal to four spaces as suggested by PEP 8, but it might be
    adjusted to match the application's styleguide.

    If `add_line_information` is set to `True` comments for the line numbers
    of the nodes are added to the output.  This can be used to spot wrong line
    number information of statement nodes.
    """
    generator = SourceGenerator(indent_with, add_line_information)
    generator.visit(node)
    return ''.join(generator.result)


class SourceGenerator(NodeVisitor):
    """This visitor is able to transform a well formed syntax tree into python
    sourcecode.  For more details have a look at the docstring of the
    `node_to_source` function.
    """

    def __init__(self, indent_with, add_line_information=False):
        self.result = []
        self.indent_with = indent_with
        self.add_line_information = add_line_information
        self.indentation = 0
        self.new_lines = 0

    def write(self, x):
        if self.new_lines:
            if self.result:
                self.result.append('\n' * self.new_lines)
            self.result.append(self.indent_with * self.indentation)
            self.new_lines = 0
        self.result.append(x)

    def newline(self, node=None, extra=0):
        self.new_lines = max(self.new_lines, 1 + extra)
        if node is not None and self.add_line_information:
            self.write('# line: %s' % node.lineno)
            self.new_lines = 1

    def body(self, statements):
        self.new_line = True
        self.indentation += 1
        for stmt in statements:
            self.visit(stmt)
        self.indentation -= 1

    def body_or_else(self, node):
        self.body(node.body)
        if node.orelse:
            self.newline()
            self.write('else:')
            self.body(node.orelse)

    def signature(self, node):
        want_comma = []
        def write_comma():
            if want_comma:
                self.write(', ')
            else:
                want_comma.append(True)

        padding = [None] * (len(node.args) - len(node.defaults))
        for arg, default in zip(node.args, padding + node.defaults):
            write_comma()
            self.visit(arg)
            if default is not None:
                self.write('=')
                self.visit(default)
        if node.vararg is not None:
            write_comma()
            self.write('*' + node.vararg)
        if node.kwarg is not None:
            write_comma()
            self.write('**' + node.kwarg)

    def decorators(self, node):
        for decorator in node.decorator_list:
            self.newline(decorator)
            self.write('@')
            self.visit(decorator)

    # Statements

    def visit_Assign(self, node):
        self.newline(node)
        for idx, target in enumerate(node.targets):
            if idx:
                self.write(', ')
            self.visit(target)
        self.write(' = ')
        self.visit(node.value)

    def visit_AugAssign(self, node):
        self.newline(node)
        self.visit(node.target)
        self.write(BINOP_SYMBOLS[type(node.op)] + '=')
        self.visit(node.value)

    def visit_ImportFrom(self, node):
        self.newline(node)
        self.write('from %s%s import ' % ('.' * node.level, node.module))
        for idx, item in enumerate(node.names):
            if idx:
                self.write(', ')
            self.write(item)

    def visit_Import(self, node):
        self.newline(node)
        for item in node.names:
            self.write('import ')
            self.visit(item)

    def visit_Expr(self, node):
        self.newline(node)
        self.generic_visit(node)

    def visit_FunctionDef(self, node):
        self.newline(extra=1)
        self.decorators(node)
        self.newline(node)
        self.write('def %s(' % node.name)
        self.signature(node.args)
        self.write('):')
        self.body(node.body)

    def visit_ClassDef(self, node):
        have_args = []
        def paren_or_comma():
            if have_args:
                self.write(', ')
            else:
                have_args.append(True)
                self.write('(')

        self.newline(extra=2)
        self.decorators(node)
        self.newline(node)
        self.write('class %s' % node.name)
        for base in node.bases:
            paren_or_comma()
            self.visit(base)
        # XXX: the if here is used to keep this module compatible
        #      with python 2.6.
        if hasattr(node, 'keywords'):
            for keyword in node.keywords:
                paren_or_comma()
                self.write(keyword.arg + '=')
                self.visit(keyword.value)
            if hasattr(node, 'starargs') and node.starargs is not None:
                paren_or_comma()
                self.write('*')
                self.visit(node.starargs)
            if hasattr(node, 'kwargs') and node.kwargs is not None:
                paren_or_comma()
                self.write('**')
                self.visit(node.kwargs)
        self.write(have_args and '):' or ':')
        self.body(node.body)

    def visit_If(self, node):
        self.newline(node)
        self.write('if ')
        self.visit(node.test)
        self.write(':')
        self.body(node.body)
        while True:
            else_ = node.orelse
            if len(else_) == 1 and isinstance(else_[0], If):
                node = else_[0]
                self.newline()
                self.write('elif ')
                self.visit(node.test)
                self.write(':')
                self.body(node.body)
            else:
                self.newline()
                self.write('else:')
                self.body(else_)
                break

    def visit_For(self, node):
        self.newline(node)
        self.write('for ')
        self.visit(node.target)
        self.write(' in ')
        self.visit(node.iter)
        self.write(':')
        self.body_or_else(node)

    def visit_While(self, node):
        self.newline(node)
        self.write('while ')
        self.visit(node.test)
        self.write(':')
        self.body_or_else(node)

    def visit_With(self, node):
        self.newline(node)
        self.write('with ')
        self.visit(node.context_expr)
        if node.optional_vars is not None:
            self.write(' as ')
            self.visit(node.optional_vars)
        self.write(':')
        self.body(node.body)

    def visit_Pass(self, node):
        self.newline(node)
        self.write('pass')

    def visit_Print(self, node):
        # XXX: python 2.6 only
        self.newline(node)
        self.write('print ')
        want_comma = False
        if node.dest is not None:
            self.write(' >> ')
            self.visit(node.dest)
            want_comma = True
        for value in node.values:
            if want_comma:
                self.write(', ')
            self.visit(value)
            want_comma = True
        if not node.nl:
            self.write(',')

    def visit_Delete(self, node):
        self.newline(node)
        self.write('del ')
        for idx, target in enumerate(node):
            if idx:
                self.write(', ')
            self.visit(target)

    def visit_TryExcept(self, node):
        self.newline(node)
        self.write('try:')
        self.body(node.body)
        for handler in node.handlers:
            self.visit(handler)

    def visit_TryFinally(self, node):
        self.newline(node)
        self.write('try:')
        self.body(node.body)
        self.newline(node)
        self.write('finally:')
        self.body(node.finalbody)

    def visit_Global(self, node):
        self.newline(node)
        self.write('global ' + ', '.join(node.names))

    def visit_Nonlocal(self, node):
        self.newline(node)
        self.write('nonlocal ' + ', '.join(node.names))

    def visit_Return(self, node):
        self.newline(node)
        self.write('return ')
        self.visit(node.value)

    def visit_Break(self, node):
        self.newline(node)
        self.write('break')

    def visit_Continue(self, node):
        self.newline(node)
        self.write('continue')

    def visit_Raise(self, node):
        # XXX: Python 2.6 / 3.0 compatibility
        self.newline(node)
        self.write('raise')
        if hasattr(node, 'exc') and node.exc is not None:
            self.write(' ')
            self.visit(node.exc)
            if node.cause is not None:
                self.write(' from ')
                self.visit(node.cause)
        elif hasattr(node, 'type') and node.type is not None:
            self.visit(node.type)
            if node.inst is not None:
                self.write(', ')
                self.visit(node.inst)
            if node.tback is not None:
                self.write(', ')
                self.visit(node.tback)

    # Expressions

    def visit_Attribute(self, node):
        self.visit(node.value)
        self.write('.' + node.attr)

    def visit_Call(self, node):
        want_comma = []
        def write_comma():
            if want_comma:
                self.write(', ')
            else:
                want_comma.append(True)

        self.visit(node.func)
        self.write('(')
        for arg in node.args:
            write_comma()
            self.visit(arg)
        for keyword in node.keywords:
            write_comma()
            self.write(keyword.arg + '=')
            self.visit(keyword.value)
        if hasattr(node, 'starargs') and node.starargs is not None:
            write_comma()
            self.write('*')
            self.visit(node.starargs)
        if hasattr(node, 'kwargs') and node.kwargs is not None:
            write_comma()
            self.write('**')
            self.visit(node.kwargs)
        self.write(')')

    def visit_Name(self, node):
        self.write(node.id)

    def visit_Str(self, node):
        self.write(repr(node.s))

    def visit_Bytes(self, node):
        self.write(repr(node.s))

    def visit_Num(self, node):
        self.write(repr(node.n))

    def visit_Tuple(self, node):
        self.write('(')
        idx = -1
        for idx, item in enumerate(node.elts):
            if idx:
                self.write(', ')
            self.visit(item)
        self.write(idx and ')' or ',)')

    def sequence_visit(left, right):
        def visit(self, node):
            self.write(left)
            for idx, item in enumerate(node.elts):
                if idx:
                    self.write(', ')
                self.visit(item)
            self.write(right)
        return visit

    visit_List = sequence_visit('[', ']')
    visit_Set = sequence_visit('{', '}')
    del sequence_visit

    def visit_Dict(self, node):
        self.write('{')
        for idx, (key, value) in enumerate(zip(node.keys, node.values)):
            if idx:
                self.write(', ')
            self.visit(key)
            self.write(': ')
            self.visit(value)
        self.write('}')

    def visit_BinOp(self, node):
        self.visit(node.left)
        self.write(' %s ' % BINOP_SYMBOLS[type(node.op)])
        self.visit(node.right)

    def visit_BoolOp(self, node):
        self.write('(')
        for idx, value in enumerate(node.values):
            if idx:
                self.write(' %s ' % BOOLOP_SYMBOLS[type(node.op)])
            self.visit(value)
        self.write(')')

    def visit_Compare(self, node):
        self.write('(')
        self.write(node.left)
        for op, right in zip(node.ops, node.comparators):
            self.write(' %s %%' % CMPOP_SYMBOLS[type(op)])
            self.visit(right)
        self.write(')')

    def visit_UnaryOp(self, node):
        self.write('(')
        op = UNARYOP_SYMBOLS[type(node.op)]
        self.write(op)
        if op == 'not':
            self.write(' ')
        self.visit(node.operand)
        self.write(')')

    def visit_Subscript(self, node):
        self.visit(node.value)
        self.write('[')
        self.visit(node.slice)
        self.write(']')

    def visit_Slice(self, node):
        if node.lower is not None:
            self.visit(node.lower)
        self.write(':')
        if node.upper is not None:
            self.visit(node.upper)
        if node.step is not None:
            self.write(':')
            if not (isinstance(node.step, Name) and node.step.id == 'None'):
                self.visit(node.step)

    def visit_ExtSlice(self, node):
        for idx, item in node.dims:
            if idx:
                self.write(', ')
            self.visit(item)

    def visit_Yield(self, node):
        self.write('yield ')
        self.visit(node.value)

    def visit_Lambda(self, node):
        self.write('lambda ')
        self.signature(node.args)
        self.write(': ')
        self.visit(node.body)

    def visit_Ellipsis(self, node):
        self.write('Ellipsis')

    def generator_visit(left, right):
        def visit(self, node):
            self.write(left)
            self.visit(node.elt)
            for comprehension in node.generators:
                self.visit(comprehension)
            self.write(right)
        return visit

    visit_ListComp = generator_visit('[', ']')
    visit_GeneratorExp = generator_visit('(', ')')
    visit_SetComp = generator_visit('{', '}')
    del generator_visit

    def visit_DictComp(self, node):
        self.write('{')
        self.visit(node.key)
        self.write(': ')
        self.visit(node.value)
        for comprehension in node.generators:
            self.visit(comprehension)
        self.write('}')

    def visit_IfExp(self, node):
        self.visit(node.body)
        self.write(' if ')
        self.visit(node.test)
        self.write(' else ')
        self.visit(node.orelse)

    def visit_Starred(self, node):
        self.write('*')
        self.visit(node.value)

    def visit_Repr(self, node):
        # XXX: python 2.6 only
        self.write('`')
        self.visit(node.value)
        self.write('`')

    # Helper Nodes

    def visit_alias(self, node):
        self.write(node.name)
        if node.asname is not None:
            self.write(' as ' + node.asname)

    def visit_comprehension(self, node):
        self.write(' for ')
        self.visit(node.target)
        self.write(' in ')
        self.visit(node.iter)
        if node.ifs:
            for if_ in node.ifs:
                self.write(' if ')
                self.visit(if_)

    def visit_excepthandler(self, node):
        self.newline(node)
        self.write('except')
        if node.type is not None:
            self.write(' ')
            self.visit(node.type)
            if node.name is not None:
                self.write(' as ')
                self.visit(node.name)
        self.write(':')
        self.body(node.body)