python类Undefined()的实例源码

def do_default(value, default_value=u'', boolean=False):
    """If the value is undefined it will return the passed default value,
    otherwise the value of the variable:

    .. sourcecode:: jinja

        {{ my_variable|default('my_variable is not defined') }}

    This will output the value of ``my_variable`` if the variable was
    defined, otherwise ``'my_variable is not defined'``. If you want
    to use default with variables that evaluate to false you have to
    set the second parameter to `true`:

    .. sourcecode:: jinja

        {{ ''|default('the string was empty', true) }}
    """
    if isinstance(value, Undefined) or (boolean and not value):
        return default_value
    return value

def do_default(value, default_value=u'', boolean=False):
    """If the value is undefined it will return the passed default value,
    otherwise the value of the variable:

    .. sourcecode:: jinja

        {{ my_variable|default('my_variable is not defined') }}

    This will output the value of ``my_variable`` if the variable was
    defined, otherwise ``'my_variable is not defined'``. If you want
    to use default with variables that evaluate to false you have to
    set the second parameter to `true`:

    .. sourcecode:: jinja

        {{ ''|default('the string was empty', true) }}
    """
    if isinstance(value, Undefined) or (boolean and not value):
        return default_value
    return value

def do_default(value, default_value=u'', boolean=False):
    """If the value is undefined it will return the passed default value,
    otherwise the value of the variable:

    .. sourcecode:: jinja

        {{ my_variable|default('my_variable is not defined') }}

    This will output the value of ``my_variable`` if the variable was
    defined, otherwise ``'my_variable is not defined'``. If you want
    to use default with variables that evaluate to false you have to
    set the second parameter to `true`:

    .. sourcecode:: jinja

        {{ ''|default('the string was empty', true) }}
    """
    if isinstance(value, Undefined) or (boolean and not value):
        return default_value
    return value

def do_default(value, default_value=u'', boolean=False):
    """If the value is undefined it will return the passed default value,
    otherwise the value of the variable:

    .. sourcecode:: jinja

        {{ my_variable|default('my_variable is not defined') }}

    This will output the value of ``my_variable`` if the variable was
    defined, otherwise ``'my_variable is not defined'``. If you want
    to use default with variables that evaluate to false you have to
    set the second parameter to `true`:

    .. sourcecode:: jinja

        {{ ''|default('the string was empty', true) }}
    """
    if isinstance(value, Undefined) or (boolean and not value):
        return default_value
    return value

def do_default(value, default_value=u'', boolean=False):
    """If the value is undefined it will return the passed default value,
    otherwise the value of the variable:

    .. sourcecode:: jinja

        {{ my_variable|default('my_variable is not defined') }}

    This will output the value of ``my_variable`` if the variable was
    defined, otherwise ``'my_variable is not defined'``. If you want
    to use default with variables that evaluate to false you have to
    set the second parameter to `true`:

    .. sourcecode:: jinja

        {{ ''|default('the string was empty', true) }}
    """
    if isinstance(value, Undefined) or (boolean and not value):
        return default_value
    return value

def do_default(value, default_value=u'', boolean=False):
    """If the value is undefined it will return the passed default value,
    otherwise the value of the variable:

    .. sourcecode:: jinja

        {{ my_variable|default('my_variable is not defined') }}

    This will output the value of ``my_variable`` if the variable was
    defined, otherwise ``'my_variable is not defined'``. If you want
    to use default with variables that evaluate to false you have to
    set the second parameter to `true`:

    .. sourcecode:: jinja

        {{ ''|default('the string was empty', true) }}
    """
    if isinstance(value, Undefined) or (boolean and not value):
        return default_value
    return value

def do_default(value, default_value=u'', boolean=False):
    """If the value is undefined it will return the passed default value,
    otherwise the value of the variable:

    .. sourcecode:: jinja

        {{ my_variable|default('my_variable is not defined') }}

    This will output the value of ``my_variable`` if the variable was
    defined, otherwise ``'my_variable is not defined'``. If you want
    to use default with variables that evaluate to false you have to
    set the second parameter to `true`:

    .. sourcecode:: jinja

        {{ ''|default('the string was empty', true) }}
    """
    if isinstance(value, Undefined) or (boolean and not value):
        return default_value
    return value

def do_default(value, default_value=u'', boolean=False):
    """If the value is undefined it will return the passed default value,
    otherwise the value of the variable:

    .. sourcecode:: jinja

        {{ my_variable|default('my_variable is not defined') }}

    This will output the value of ``my_variable`` if the variable was
    defined, otherwise ``'my_variable is not defined'``. If you want
    to use default with variables that evaluate to false you have to
    set the second parameter to `true`:

    .. sourcecode:: jinja

        {{ ''|default('the string was empty', true) }}
    """
    if isinstance(value, Undefined) or (boolean and not value):
        return default_value
    return value

def do_default(value, default_value=u'', boolean=False):
    """If the value is undefined it will return the passed default value,
    otherwise the value of the variable:

    .. sourcecode:: jinja

        {{ my_variable|default('my_variable is not defined') }}

    This will output the value of ``my_variable`` if the variable was
    defined, otherwise ``'my_variable is not defined'``. If you want
    to use default with variables that evaluate to false you have to
    set the second parameter to `true`:

    .. sourcecode:: jinja

        {{ ''|default('the string was empty', true) }}
    """
    if isinstance(value, Undefined) or (boolean and not value):
        return default_value
    return value

def _environment_sanity_check(environment):
    """Perform a sanity check on the environment."""
    assert issubclass(environment.undefined, Undefined), 'undefined must ' \
        'be a subclass of undefined because filters depend on it.'
    assert environment.block_start_string != \
        environment.variable_start_string != \
        environment.comment_start_string, 'block, variable and comment ' \
        'start strings must be different'
    assert environment.newline_sequence in ('\r', '\r\n', '\n'), \
        'newline_sequence set to unknown line ending string.'
    return environment

def __new__(cls, source,
                block_start_string=BLOCK_START_STRING,
                block_end_string=BLOCK_END_STRING,
                variable_start_string=VARIABLE_START_STRING,
                variable_end_string=VARIABLE_END_STRING,
                comment_start_string=COMMENT_START_STRING,
                comment_end_string=COMMENT_END_STRING,
                line_statement_prefix=LINE_STATEMENT_PREFIX,
                line_comment_prefix=LINE_COMMENT_PREFIX,
                trim_blocks=TRIM_BLOCKS,
                lstrip_blocks=LSTRIP_BLOCKS,
                newline_sequence=NEWLINE_SEQUENCE,
                keep_trailing_newline=KEEP_TRAILING_NEWLINE,
                extensions=(),
                optimized=True,
                undefined=Undefined,
                finalize=None,
                autoescape=False):
        env = get_spontaneous_environment(
            block_start_string, block_end_string, variable_start_string,
            variable_end_string, comment_start_string, comment_end_string,
            line_statement_prefix, line_comment_prefix, trim_blocks,
            lstrip_blocks, newline_sequence, keep_trailing_newline,
            frozenset(extensions), optimized, undefined, finalize, autoescape,
            None, 0, False, None)
        return env.from_string(source, template_class=cls)

def __call__(self, *args, **kwargs):
        context = self._template.new_context(dict(*args, **kwargs))
        consume(self._template.root_render_func(context))
        rv = context.vars['result']
        if self._undefined_to_none and isinstance(rv, Undefined):
            rv = None
        return rv

def do_xmlattr(_eval_ctx, d, autospace=True):
    """Create an SGML/XML attribute string based on the items in a dict.
    All values that are neither `none` nor `undefined` are automatically
    escaped:

    .. sourcecode:: html+jinja

        <ul{{ {'class': 'my_list', 'missing': none,
                'id': 'list-%d'|format(variable)}|xmlattr }}>
        ...
        </ul>

    Results in something like this:

    .. sourcecode:: html

        <ul class="my_list" id="list-42">
        ...
        </ul>

    As you can see it automatically prepends a space in front of the item
    if the filter returned something unless the second parameter is false.
    """
    rv = u' '.join(
        u'%s="%s"' % (escape(key), escape(value))
        for key, value in iteritems(d)
        if value is not None and not isinstance(value, Undefined)
    )
    if autospace and rv:
        rv = u' ' + rv
    if _eval_ctx.autoescape:
        rv = Markup(rv)
    return rv

def test_defined(value):
    """Return true if the variable is defined:

    .. sourcecode:: jinja

        {% if variable is defined %}
            value of variable: {{ variable }}
        {% else %}
            variable is not defined
        {% endif %}

    See the :func:`default` filter for a simple way to set undefined
    variables.
    """
    return not isinstance(value, Undefined)

def test_undefined(value):
    """Like :func:`defined` but the other way round."""
    return isinstance(value, Undefined)

def is_undefined(obj):
    """Check if the object passed is undefined.  This does nothing more than
    performing an instance check against :class:`Undefined` but looks nicer.
    This can be used for custom filters or tests that want to react to
    undefined variables.  For example a custom default filter can look like
    this::

        def default(var, default=''):
            if is_undefined(var):
                return default
            return var
    """
    from jinja2.runtime import Undefined
    return isinstance(obj, Undefined)

def _environment_sanity_check(environment):
    """Perform a sanity check on the environment."""
    assert issubclass(environment.undefined, Undefined), 'undefined must ' \
        'be a subclass of undefined because filters depend on it.'
    assert environment.block_start_string != \
        environment.variable_start_string != \
        environment.comment_start_string, 'block, variable and comment ' \
        'start strings must be different'
    assert environment.newline_sequence in ('\r', '\r\n', '\n'), \
        'newline_sequence set to unknown line ending string.'
    return environment

def __new__(cls, source,
                block_start_string=BLOCK_START_STRING,
                block_end_string=BLOCK_END_STRING,
                variable_start_string=VARIABLE_START_STRING,
                variable_end_string=VARIABLE_END_STRING,
                comment_start_string=COMMENT_START_STRING,
                comment_end_string=COMMENT_END_STRING,
                line_statement_prefix=LINE_STATEMENT_PREFIX,
                line_comment_prefix=LINE_COMMENT_PREFIX,
                trim_blocks=TRIM_BLOCKS,
                lstrip_blocks=LSTRIP_BLOCKS,
                newline_sequence=NEWLINE_SEQUENCE,
                keep_trailing_newline=KEEP_TRAILING_NEWLINE,
                extensions=(),
                optimized=True,
                undefined=Undefined,
                finalize=None,
                autoescape=False):
        env = get_spontaneous_environment(
            block_start_string, block_end_string, variable_start_string,
            variable_end_string, comment_start_string, comment_end_string,
            line_statement_prefix, line_comment_prefix, trim_blocks,
            lstrip_blocks, newline_sequence, keep_trailing_newline,
            frozenset(extensions), optimized, undefined, finalize, autoescape,
            None, 0, False, None)
        return env.from_string(source, template_class=cls)

def __call__(self, *args, **kwargs):
        context = self._template.new_context(dict(*args, **kwargs))
        consume(self._template.root_render_func(context))
        rv = context.vars['result']
        if self._undefined_to_none and isinstance(rv, Undefined):
            rv = None
        return rv

def do_xmlattr(_eval_ctx, d, autospace=True):
    """Create an SGML/XML attribute string based on the items in a dict.
    All values that are neither `none` nor `undefined` are automatically
    escaped:

    .. sourcecode:: html+jinja

        <ul{{ {'class': 'my_list', 'missing': none,
                'id': 'list-%d'|format(variable)}|xmlattr }}>
        ...
        </ul>

    Results in something like this:

    .. sourcecode:: html

        <ul class="my_list" id="list-42">
        ...
        </ul>

    As you can see it automatically prepends a space in front of the item
    if the filter returned something unless the second parameter is false.
    """
    rv = u' '.join(
        u'%s="%s"' % (escape(key), escape(value))
        for key, value in iteritems(d)
        if value is not None and not isinstance(value, Undefined)
    )
    if autospace and rv:
        rv = u' ' + rv
    if _eval_ctx.autoescape:
        rv = Markup(rv)
    return rv

def test_defined(value):
    """Return true if the variable is defined:

    .. sourcecode:: jinja

        {% if variable is defined %}
            value of variable: {{ variable }}
        {% else %}
            variable is not defined
        {% endif %}

    See the :func:`default` filter for a simple way to set undefined
    variables.
    """
    return not isinstance(value, Undefined)

def test_undefined(value):
    """Like :func:`defined` but the other way round."""
    return isinstance(value, Undefined)

def is_undefined(obj):
    """Check if the object passed is undefined.  This does nothing more than
    performing an instance check against :class:`Undefined` but looks nicer.
    This can be used for custom filters or tests that want to react to
    undefined variables.  For example a custom default filter can look like
    this::

        def default(var, default=''):
            if is_undefined(var):
                return default
            return var
    """
    from jinja2.runtime import Undefined
    return isinstance(obj, Undefined)

def _environment_sanity_check(environment):
    """Perform a sanity check on the environment."""
    assert issubclass(environment.undefined, Undefined), 'undefined must ' \
        'be a subclass of undefined because filters depend on it.'
    assert environment.block_start_string != \
        environment.variable_start_string != \
        environment.comment_start_string, 'block, variable and comment ' \
        'start strings must be different'
    assert environment.newline_sequence in ('\r', '\r\n', '\n'), \
        'newline_sequence set to unknown line ending string.'
    return environment

def __new__(cls, source,
                block_start_string=BLOCK_START_STRING,
                block_end_string=BLOCK_END_STRING,
                variable_start_string=VARIABLE_START_STRING,
                variable_end_string=VARIABLE_END_STRING,
                comment_start_string=COMMENT_START_STRING,
                comment_end_string=COMMENT_END_STRING,
                line_statement_prefix=LINE_STATEMENT_PREFIX,
                line_comment_prefix=LINE_COMMENT_PREFIX,
                trim_blocks=TRIM_BLOCKS,
                lstrip_blocks=LSTRIP_BLOCKS,
                newline_sequence=NEWLINE_SEQUENCE,
                keep_trailing_newline=KEEP_TRAILING_NEWLINE,
                extensions=(),
                optimized=True,
                undefined=Undefined,
                finalize=None,
                autoescape=False):
        env = get_spontaneous_environment(
            block_start_string, block_end_string, variable_start_string,
            variable_end_string, comment_start_string, comment_end_string,
            line_statement_prefix, line_comment_prefix, trim_blocks,
            lstrip_blocks, newline_sequence, keep_trailing_newline,
            frozenset(extensions), optimized, undefined, finalize, autoescape,
            None, 0, False, None)
        return env.from_string(source, template_class=cls)

def __call__(self, *args, **kwargs):
        context = self._template.new_context(dict(*args, **kwargs))
        consume(self._template.root_render_func(context))
        rv = context.vars['result']
        if self._undefined_to_none and isinstance(rv, Undefined):
            rv = None
        return rv

def do_xmlattr(_eval_ctx, d, autospace=True):
    """Create an SGML/XML attribute string based on the items in a dict.
    All values that are neither `none` nor `undefined` are automatically
    escaped:

    .. sourcecode:: html+jinja

        <ul{{ {'class': 'my_list', 'missing': none,
                'id': 'list-%d'|format(variable)}|xmlattr }}>
        ...
        </ul>

    Results in something like this:

    .. sourcecode:: html

        <ul class="my_list" id="list-42">
        ...
        </ul>

    As you can see it automatically prepends a space in front of the item
    if the filter returned something unless the second parameter is false.
    """
    rv = u' '.join(
        u'%s="%s"' % (escape(key), escape(value))
        for key, value in iteritems(d)
        if value is not None and not isinstance(value, Undefined)
    )
    if autospace and rv:
        rv = u' ' + rv
    if _eval_ctx.autoescape:
        rv = Markup(rv)
    return rv

def test_defined(value):
    """Return true if the variable is defined:

    .. sourcecode:: jinja

        {% if variable is defined %}
            value of variable: {{ variable }}
        {% else %}
            variable is not defined
        {% endif %}

    See the :func:`default` filter for a simple way to set undefined
    variables.
    """
    return not isinstance(value, Undefined)

def test_undefined(value):
    """Like :func:`defined` but the other way round."""
    return isinstance(value, Undefined)

def is_undefined(obj):
    """Check if the object passed is undefined.  This does nothing more than
    performing an instance check against :class:`Undefined` but looks nicer.
    This can be used for custom filters or tests that want to react to
    undefined variables.  For example a custom default filter can look like
    this::

        def default(var, default=''):
            if is_undefined(var):
                return default
            return var
    """
    from jinja2.runtime import Undefined
    return isinstance(obj, Undefined)