diff options
Diffstat (limited to 'forum/templatetags/smart_if.py')
-rw-r--r-- | forum/templatetags/smart_if.py | 802 |
1 files changed, 401 insertions, 401 deletions
diff --git a/forum/templatetags/smart_if.py b/forum/templatetags/smart_if.py index a8fc1944..ca3b43fe 100644 --- a/forum/templatetags/smart_if.py +++ b/forum/templatetags/smart_if.py @@ -1,401 +1,401 @@ -"""
-A smarter {% if %} tag for django templates.
-
-While retaining current Django functionality, it also handles equality,
-greater than and less than operators. Some common case examples::
-
- {% if articles|length >= 5 %}...{% endif %}
- {% if "ifnotequal tag" != "beautiful" %}...{% endif %}
-"""
-import unittest
-from django import template
-
-
-register = template.Library()
-
-
-#==============================================================================
-# Calculation objects
-#==============================================================================
-
-class BaseCalc(object):
- def __init__(self, var1, var2=None, negate=False):
- self.var1 = var1
- self.var2 = var2
- self.negate = negate
-
- def resolve(self, context):
- try:
- var1, var2 = self.resolve_vars(context)
- outcome = self.calculate(var1, var2)
- except:
- outcome = False
- if self.negate:
- return not outcome
- return outcome
-
- def resolve_vars(self, context):
- var2 = self.var2 and self.var2.resolve(context)
- return self.var1.resolve(context), var2
-
- def calculate(self, var1, var2):
- raise NotImplementedError()
-
-
-class Or(BaseCalc):
- def calculate(self, var1, var2):
- return var1 or var2
-
-
-class And(BaseCalc):
- def calculate(self, var1, var2):
- return var1 and var2
-
-
-class Equals(BaseCalc):
- def calculate(self, var1, var2):
- return var1 == var2
-
-
-class Greater(BaseCalc):
- def calculate(self, var1, var2):
- return var1 > var2
-
-
-class GreaterOrEqual(BaseCalc):
- def calculate(self, var1, var2):
- return var1 >= var2
-
-
-class In(BaseCalc):
- def calculate(self, var1, var2):
- return var1 in var2
-
-
-#==============================================================================
-# Tests
-#==============================================================================
-
-class TestVar(object):
- """
- A basic self-resolvable object similar to a Django template variable. Used
- to assist with tests.
- """
- def __init__(self, value):
- self.value = value
-
- def resolve(self, context):
- return self.value
-
-
-class SmartIfTests(unittest.TestCase):
- def setUp(self):
- self.true = TestVar(True)
- self.false = TestVar(False)
- self.high = TestVar(9000)
- self.low = TestVar(1)
-
- def assertCalc(self, calc, context=None):
- """
- Test a calculation is True, also checking the inverse "negate" case.
- """
- context = context or {}
- self.assert_(calc.resolve(context))
- calc.negate = not calc.negate
- self.assertFalse(calc.resolve(context))
-
- def assertCalcFalse(self, calc, context=None):
- """
- Test a calculation is False, also checking the inverse "negate" case.
- """
- context = context or {}
- self.assertFalse(calc.resolve(context))
- calc.negate = not calc.negate
- self.assert_(calc.resolve(context))
-
- def test_or(self):
- self.assertCalc(Or(self.true))
- self.assertCalcFalse(Or(self.false))
- self.assertCalc(Or(self.true, self.true))
- self.assertCalc(Or(self.true, self.false))
- self.assertCalc(Or(self.false, self.true))
- self.assertCalcFalse(Or(self.false, self.false))
-
- def test_and(self):
- self.assertCalc(And(self.true, self.true))
- self.assertCalcFalse(And(self.true, self.false))
- self.assertCalcFalse(And(self.false, self.true))
- self.assertCalcFalse(And(self.false, self.false))
-
- def test_equals(self):
- self.assertCalc(Equals(self.low, self.low))
- self.assertCalcFalse(Equals(self.low, self.high))
-
- def test_greater(self):
- self.assertCalc(Greater(self.high, self.low))
- self.assertCalcFalse(Greater(self.low, self.low))
- self.assertCalcFalse(Greater(self.low, self.high))
-
- def test_greater_or_equal(self):
- self.assertCalc(GreaterOrEqual(self.high, self.low))
- self.assertCalc(GreaterOrEqual(self.low, self.low))
- self.assertCalcFalse(GreaterOrEqual(self.low, self.high))
-
- def test_in(self):
- list_ = TestVar([1,2,3])
- invalid_list = TestVar(None)
- self.assertCalc(In(self.low, list_))
- self.assertCalcFalse(In(self.low, invalid_list))
-
- def test_parse_bits(self):
- var = IfParser([True]).parse()
- self.assert_(var.resolve({}))
- var = IfParser([False]).parse()
- self.assertFalse(var.resolve({}))
-
- var = IfParser([False, 'or', True]).parse()
- self.assert_(var.resolve({}))
-
- var = IfParser([False, 'and', True]).parse()
- self.assertFalse(var.resolve({}))
-
- var = IfParser(['not', False, 'and', 'not', False]).parse()
- self.assert_(var.resolve({}))
-
- var = IfParser(['not', 'not', True]).parse()
- self.assert_(var.resolve({}))
-
- var = IfParser([1, '=', 1]).parse()
- self.assert_(var.resolve({}))
-
- var = IfParser([1, 'not', '=', 1]).parse()
- self.assertFalse(var.resolve({}))
-
- var = IfParser([1, 'not', 'not', '=', 1]).parse()
- self.assert_(var.resolve({}))
-
- var = IfParser([1, '!=', 1]).parse()
- self.assertFalse(var.resolve({}))
-
- var = IfParser([3, '>', 2]).parse()
- self.assert_(var.resolve({}))
-
- var = IfParser([1, '<', 2]).parse()
- self.assert_(var.resolve({}))
-
- var = IfParser([2, 'not', 'in', [2, 3]]).parse()
- self.assertFalse(var.resolve({}))
-
- var = IfParser([1, 'or', 1, '=', 2]).parse()
- self.assert_(var.resolve({}))
-
- def test_boolean(self):
- var = IfParser([True, 'and', True, 'and', True]).parse()
- self.assert_(var.resolve({}))
- var = IfParser([False, 'or', False, 'or', True]).parse()
- self.assert_(var.resolve({}))
- var = IfParser([True, 'and', False, 'or', True]).parse()
- self.assert_(var.resolve({}))
- var = IfParser([False, 'or', True, 'and', True]).parse()
- self.assert_(var.resolve({}))
-
- var = IfParser([True, 'and', True, 'and', False]).parse()
- self.assertFalse(var.resolve({}))
- var = IfParser([False, 'or', False, 'or', False]).parse()
- self.assertFalse(var.resolve({}))
- var = IfParser([False, 'or', True, 'and', False]).parse()
- self.assertFalse(var.resolve({}))
- var = IfParser([False, 'and', True, 'or', False]).parse()
- self.assertFalse(var.resolve({}))
-
- def test_invalid(self):
- self.assertRaises(ValueError, IfParser(['not']).parse)
- self.assertRaises(ValueError, IfParser(['==']).parse)
- self.assertRaises(ValueError, IfParser([1, 'in']).parse)
- self.assertRaises(ValueError, IfParser([1, '>', 'in']).parse)
- self.assertRaises(ValueError, IfParser([1, '==', 'not', 'not']).parse)
- self.assertRaises(ValueError, IfParser([1, 2]).parse)
-
-
-OPERATORS = {
- '=': (Equals, True),
- '==': (Equals, True),
- '!=': (Equals, False),
- '>': (Greater, True),
- '>=': (GreaterOrEqual, True),
- '<=': (Greater, False),
- '<': (GreaterOrEqual, False),
- 'or': (Or, True),
- 'and': (And, True),
- 'in': (In, True),
-}
-BOOL_OPERATORS = ('or', 'and')
-
-
-class IfParser(object):
- error_class = ValueError
-
- def __init__(self, tokens):
- self.tokens = tokens
-
- def _get_tokens(self):
- return self._tokens
-
- def _set_tokens(self, tokens):
- self._tokens = tokens
- self.len = len(tokens)
- self.pos = 0
-
- tokens = property(_get_tokens, _set_tokens)
-
- def parse(self):
- if self.at_end():
- raise self.error_class('No variables provided.')
- var1 = self.get_bool_var()
- while not self.at_end():
- op, negate = self.get_operator()
- var2 = self.get_bool_var()
- var1 = op(var1, var2, negate=negate)
- return var1
-
- def get_token(self, eof_message=None, lookahead=False):
- negate = True
- token = None
- pos = self.pos
- while token is None or token == 'not':
- if pos >= self.len:
- if eof_message is None:
- raise self.error_class()
- raise self.error_class(eof_message)
- token = self.tokens[pos]
- negate = not negate
- pos += 1
- if not lookahead:
- self.pos = pos
- return token, negate
-
- def at_end(self):
- return self.pos >= self.len
-
- def create_var(self, value):
- return TestVar(value)
-
- def get_bool_var(self):
- """
- Returns either a variable by itself or a non-boolean operation (such as
- ``x == 0`` or ``x < 0``).
-
- This is needed to keep correct precedence for boolean operations (i.e.
- ``x or x == 0`` should be ``x or (x == 0)``, not ``(x or x) == 0``).
- """
- var = self.get_var()
- if not self.at_end():
- op_token = self.get_token(lookahead=True)[0]
- if isinstance(op_token, basestring) and (op_token not in
- BOOL_OPERATORS):
- op, negate = self.get_operator()
- return op(var, self.get_var(), negate=negate)
- return var
-
- def get_var(self):
- token, negate = self.get_token('Reached end of statement, still '
- 'expecting a variable.')
- if isinstance(token, basestring) and token in OPERATORS:
- raise self.error_class('Expected variable, got operator (%s).' %
- token)
- var = self.create_var(token)
- if negate:
- return Or(var, negate=True)
- return var
-
- def get_operator(self):
- token, negate = self.get_token('Reached end of statement, still '
- 'expecting an operator.')
- if not isinstance(token, basestring) or token not in OPERATORS:
- raise self.error_class('%s is not a valid operator.' % token)
- if self.at_end():
- raise self.error_class('No variable provided after "%s".' % token)
- op, true = OPERATORS[token]
- if not true:
- negate = not negate
- return op, negate
-
-
-#==============================================================================
-# Actual templatetag code.
-#==============================================================================
-
-class TemplateIfParser(IfParser):
- error_class = template.TemplateSyntaxError
-
- def __init__(self, parser, *args, **kwargs):
- self.template_parser = parser
- return super(TemplateIfParser, self).__init__(*args, **kwargs)
-
- def create_var(self, value):
- return self.template_parser.compile_filter(value)
-
-
-class SmartIfNode(template.Node):
- def __init__(self, var, nodelist_true, nodelist_false=None):
- self.nodelist_true, self.nodelist_false = nodelist_true, nodelist_false
- self.var = var
-
- def render(self, context):
- if self.var.resolve(context):
- return self.nodelist_true.render(context)
- if self.nodelist_false:
- return self.nodelist_false.render(context)
- return ''
-
- def __repr__(self):
- return "<Smart If node>"
-
- def __iter__(self):
- for node in self.nodelist_true:
- yield node
- if self.nodelist_false:
- for node in self.nodelist_false:
- yield node
-
- def get_nodes_by_type(self, nodetype):
- nodes = []
- if isinstance(self, nodetype):
- nodes.append(self)
- nodes.extend(self.nodelist_true.get_nodes_by_type(nodetype))
- if self.nodelist_false:
- nodes.extend(self.nodelist_false.get_nodes_by_type(nodetype))
- return nodes
-
-
-@register.tag('if')
-def smart_if(parser, token):
- """
- A smarter {% if %} tag for django templates.
-
- While retaining current Django functionality, it also handles equality,
- greater than and less than operators. Some common case examples::
-
- {% if articles|length >= 5 %}...{% endif %}
- {% if "ifnotequal tag" != "beautiful" %}...{% endif %}
-
- Arguments and operators _must_ have a space between them, so
- ``{% if 1>2 %}`` is not a valid smart if tag.
-
- All supported operators are: ``or``, ``and``, ``in``, ``=`` (or ``==``),
- ``!=``, ``>``, ``>=``, ``<`` and ``<=``.
- """
- bits = token.split_contents()[1:]
- var = TemplateIfParser(parser, bits).parse()
- nodelist_true = parser.parse(('else', 'endif'))
- token = parser.next_token()
- if token.contents == 'else':
- nodelist_false = parser.parse(('endif',))
- parser.delete_first_token()
- else:
- nodelist_false = None
- return SmartIfNode(var, nodelist_true, nodelist_false)
-
-
-if __name__ == '__main__':
- unittest.main()
+""" +A smarter {% if %} tag for django templates. + +While retaining current Django functionality, it also handles equality, +greater than and less than operators. Some common case examples:: + + {% if articles|length >= 5 %}...{% endif %} + {% if "ifnotequal tag" != "beautiful" %}...{% endif %} +""" +import unittest +from django import template + + +register = template.Library() + + +#============================================================================== +# Calculation objects +#============================================================================== + +class BaseCalc(object): + def __init__(self, var1, var2=None, negate=False): + self.var1 = var1 + self.var2 = var2 + self.negate = negate + + def resolve(self, context): + try: + var1, var2 = self.resolve_vars(context) + outcome = self.calculate(var1, var2) + except: + outcome = False + if self.negate: + return not outcome + return outcome + + def resolve_vars(self, context): + var2 = self.var2 and self.var2.resolve(context) + return self.var1.resolve(context), var2 + + def calculate(self, var1, var2): + raise NotImplementedError() + + +class Or(BaseCalc): + def calculate(self, var1, var2): + return var1 or var2 + + +class And(BaseCalc): + def calculate(self, var1, var2): + return var1 and var2 + + +class Equals(BaseCalc): + def calculate(self, var1, var2): + return var1 == var2 + + +class Greater(BaseCalc): + def calculate(self, var1, var2): + return var1 > var2 + + +class GreaterOrEqual(BaseCalc): + def calculate(self, var1, var2): + return var1 >= var2 + + +class In(BaseCalc): + def calculate(self, var1, var2): + return var1 in var2 + + +#============================================================================== +# Tests +#============================================================================== + +class TestVar(object): + """ + A basic self-resolvable object similar to a Django template variable. Used + to assist with tests. + """ + def __init__(self, value): + self.value = value + + def resolve(self, context): + return self.value + + +class SmartIfTests(unittest.TestCase): + def setUp(self): + self.true = TestVar(True) + self.false = TestVar(False) + self.high = TestVar(9000) + self.low = TestVar(1) + + def assertCalc(self, calc, context=None): + """ + Test a calculation is True, also checking the inverse "negate" case. + """ + context = context or {} + self.assert_(calc.resolve(context)) + calc.negate = not calc.negate + self.assertFalse(calc.resolve(context)) + + def assertCalcFalse(self, calc, context=None): + """ + Test a calculation is False, also checking the inverse "negate" case. + """ + context = context or {} + self.assertFalse(calc.resolve(context)) + calc.negate = not calc.negate + self.assert_(calc.resolve(context)) + + def test_or(self): + self.assertCalc(Or(self.true)) + self.assertCalcFalse(Or(self.false)) + self.assertCalc(Or(self.true, self.true)) + self.assertCalc(Or(self.true, self.false)) + self.assertCalc(Or(self.false, self.true)) + self.assertCalcFalse(Or(self.false, self.false)) + + def test_and(self): + self.assertCalc(And(self.true, self.true)) + self.assertCalcFalse(And(self.true, self.false)) + self.assertCalcFalse(And(self.false, self.true)) + self.assertCalcFalse(And(self.false, self.false)) + + def test_equals(self): + self.assertCalc(Equals(self.low, self.low)) + self.assertCalcFalse(Equals(self.low, self.high)) + + def test_greater(self): + self.assertCalc(Greater(self.high, self.low)) + self.assertCalcFalse(Greater(self.low, self.low)) + self.assertCalcFalse(Greater(self.low, self.high)) + + def test_greater_or_equal(self): + self.assertCalc(GreaterOrEqual(self.high, self.low)) + self.assertCalc(GreaterOrEqual(self.low, self.low)) + self.assertCalcFalse(GreaterOrEqual(self.low, self.high)) + + def test_in(self): + list_ = TestVar([1,2,3]) + invalid_list = TestVar(None) + self.assertCalc(In(self.low, list_)) + self.assertCalcFalse(In(self.low, invalid_list)) + + def test_parse_bits(self): + var = IfParser([True]).parse() + self.assert_(var.resolve({})) + var = IfParser([False]).parse() + self.assertFalse(var.resolve({})) + + var = IfParser([False, 'or', True]).parse() + self.assert_(var.resolve({})) + + var = IfParser([False, 'and', True]).parse() + self.assertFalse(var.resolve({})) + + var = IfParser(['not', False, 'and', 'not', False]).parse() + self.assert_(var.resolve({})) + + var = IfParser(['not', 'not', True]).parse() + self.assert_(var.resolve({})) + + var = IfParser([1, '=', 1]).parse() + self.assert_(var.resolve({})) + + var = IfParser([1, 'not', '=', 1]).parse() + self.assertFalse(var.resolve({})) + + var = IfParser([1, 'not', 'not', '=', 1]).parse() + self.assert_(var.resolve({})) + + var = IfParser([1, '!=', 1]).parse() + self.assertFalse(var.resolve({})) + + var = IfParser([3, '>', 2]).parse() + self.assert_(var.resolve({})) + + var = IfParser([1, '<', 2]).parse() + self.assert_(var.resolve({})) + + var = IfParser([2, 'not', 'in', [2, 3]]).parse() + self.assertFalse(var.resolve({})) + + var = IfParser([1, 'or', 1, '=', 2]).parse() + self.assert_(var.resolve({})) + + def test_boolean(self): + var = IfParser([True, 'and', True, 'and', True]).parse() + self.assert_(var.resolve({})) + var = IfParser([False, 'or', False, 'or', True]).parse() + self.assert_(var.resolve({})) + var = IfParser([True, 'and', False, 'or', True]).parse() + self.assert_(var.resolve({})) + var = IfParser([False, 'or', True, 'and', True]).parse() + self.assert_(var.resolve({})) + + var = IfParser([True, 'and', True, 'and', False]).parse() + self.assertFalse(var.resolve({})) + var = IfParser([False, 'or', False, 'or', False]).parse() + self.assertFalse(var.resolve({})) + var = IfParser([False, 'or', True, 'and', False]).parse() + self.assertFalse(var.resolve({})) + var = IfParser([False, 'and', True, 'or', False]).parse() + self.assertFalse(var.resolve({})) + + def test_invalid(self): + self.assertRaises(ValueError, IfParser(['not']).parse) + self.assertRaises(ValueError, IfParser(['==']).parse) + self.assertRaises(ValueError, IfParser([1, 'in']).parse) + self.assertRaises(ValueError, IfParser([1, '>', 'in']).parse) + self.assertRaises(ValueError, IfParser([1, '==', 'not', 'not']).parse) + self.assertRaises(ValueError, IfParser([1, 2]).parse) + + +OPERATORS = { + '=': (Equals, True), + '==': (Equals, True), + '!=': (Equals, False), + '>': (Greater, True), + '>=': (GreaterOrEqual, True), + '<=': (Greater, False), + '<': (GreaterOrEqual, False), + 'or': (Or, True), + 'and': (And, True), + 'in': (In, True), +} +BOOL_OPERATORS = ('or', 'and') + + +class IfParser(object): + error_class = ValueError + + def __init__(self, tokens): + self.tokens = tokens + + def _get_tokens(self): + return self._tokens + + def _set_tokens(self, tokens): + self._tokens = tokens + self.len = len(tokens) + self.pos = 0 + + tokens = property(_get_tokens, _set_tokens) + + def parse(self): + if self.at_end(): + raise self.error_class('No variables provided.') + var1 = self.get_bool_var() + while not self.at_end(): + op, negate = self.get_operator() + var2 = self.get_bool_var() + var1 = op(var1, var2, negate=negate) + return var1 + + def get_token(self, eof_message=None, lookahead=False): + negate = True + token = None + pos = self.pos + while token is None or token == 'not': + if pos >= self.len: + if eof_message is None: + raise self.error_class() + raise self.error_class(eof_message) + token = self.tokens[pos] + negate = not negate + pos += 1 + if not lookahead: + self.pos = pos + return token, negate + + def at_end(self): + return self.pos >= self.len + + def create_var(self, value): + return TestVar(value) + + def get_bool_var(self): + """ + Returns either a variable by itself or a non-boolean operation (such as + ``x == 0`` or ``x < 0``). + + This is needed to keep correct precedence for boolean operations (i.e. + ``x or x == 0`` should be ``x or (x == 0)``, not ``(x or x) == 0``). + """ + var = self.get_var() + if not self.at_end(): + op_token = self.get_token(lookahead=True)[0] + if isinstance(op_token, basestring) and (op_token not in + BOOL_OPERATORS): + op, negate = self.get_operator() + return op(var, self.get_var(), negate=negate) + return var + + def get_var(self): + token, negate = self.get_token('Reached end of statement, still ' + 'expecting a variable.') + if isinstance(token, basestring) and token in OPERATORS: + raise self.error_class('Expected variable, got operator (%s).' % + token) + var = self.create_var(token) + if negate: + return Or(var, negate=True) + return var + + def get_operator(self): + token, negate = self.get_token('Reached end of statement, still ' + 'expecting an operator.') + if not isinstance(token, basestring) or token not in OPERATORS: + raise self.error_class('%s is not a valid operator.' % token) + if self.at_end(): + raise self.error_class('No variable provided after "%s".' % token) + op, true = OPERATORS[token] + if not true: + negate = not negate + return op, negate + + +#============================================================================== +# Actual templatetag code. +#============================================================================== + +class TemplateIfParser(IfParser): + error_class = template.TemplateSyntaxError + + def __init__(self, parser, *args, **kwargs): + self.template_parser = parser + return super(TemplateIfParser, self).__init__(*args, **kwargs) + + def create_var(self, value): + return self.template_parser.compile_filter(value) + + +class SmartIfNode(template.Node): + def __init__(self, var, nodelist_true, nodelist_false=None): + self.nodelist_true, self.nodelist_false = nodelist_true, nodelist_false + self.var = var + + def render(self, context): + if self.var.resolve(context): + return self.nodelist_true.render(context) + if self.nodelist_false: + return self.nodelist_false.render(context) + return '' + + def __repr__(self): + return "<Smart If node>" + + def __iter__(self): + for node in self.nodelist_true: + yield node + if self.nodelist_false: + for node in self.nodelist_false: + yield node + + def get_nodes_by_type(self, nodetype): + nodes = [] + if isinstance(self, nodetype): + nodes.append(self) + nodes.extend(self.nodelist_true.get_nodes_by_type(nodetype)) + if self.nodelist_false: + nodes.extend(self.nodelist_false.get_nodes_by_type(nodetype)) + return nodes + + +@register.tag('if') +def smart_if(parser, token): + """ + A smarter {% if %} tag for django templates. + + While retaining current Django functionality, it also handles equality, + greater than and less than operators. Some common case examples:: + + {% if articles|length >= 5 %}...{% endif %} + {% if "ifnotequal tag" != "beautiful" %}...{% endif %} + + Arguments and operators _must_ have a space between them, so + ``{% if 1>2 %}`` is not a valid smart if tag. + + All supported operators are: ``or``, ``and``, ``in``, ``=`` (or ``==``), + ``!=``, ``>``, ``>=``, ``<`` and ``<=``. + """ + bits = token.split_contents()[1:] + var = TemplateIfParser(parser, bits).parse() + nodelist_true = parser.parse(('else', 'endif')) + token = parser.next_token() + if token.contents == 'else': + nodelist_false = parser.parse(('endif',)) + parser.delete_first_token() + else: + nodelist_false = None + return SmartIfNode(var, nodelist_true, nodelist_false) + + +if __name__ == '__main__': + unittest.main() |