Added extended if tag, until the migration to Django 1.2. Now only shows the options that are available

hr/templatetags/if_extra.py

@@ -0,0 +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()

templates/hr/applications/view.html

@@ -1,6 +1,7 @@
 {% extends "base.html" %}
 
 {% load humanize %}
+{% load if_extra %}
 
 {% block title %}View Application{% endblock %}
 
@@ -13,15 +14,26 @@
 <li>Application Status: <b>{{ app.status_description }}</b></li>
 </ul>
 
+{% ifnotequal app.status 5 %}
 <h3>Actions</h3>
 <p>
-{% ifequal app.status 0 %}
-<a href="{% url hr.views.update_application app.id 1 %}">Submit Application</a>
-{% endifequal %}
-
-{% if hrstaff %}
-<a href="{% url hr.views.add_note app.id %}">Add Note</a>, <a href="{% url hr.views.reject_application app.id %}">Reject Application</a>,  <a href="{% url hr.views.accept_application app.id %}">Accept Application</a>
+{% if app.status < 1 %}
+<a href="{% url hr.views.update_application app.id 1 %}">Submit Application</a>,&nbsp;
 {% endif %}
+{% if hrstaff %}
+<a href="{% url hr.views.add_note app.id %}">Add Note</a>,
+{% if app.status < 2 or app.status = 4 %}
+<a href="{% url hr.views.reject_application app.id %}">Reject Application</a>,&nbsp; 
+<a href="{% url hr.views.accept_application app.id %}">Accept Application</a>,&nbsp;
+{% ifnotequal app.status 4 %}
+<a href="{% url hr.views.update_application app.id 4 %}">Mark as In Query</a>,&nbsp;
+{% endifnotequal %}
+{% endif %}
+{% ifequal app.status 3 %}
+<a href="{% url hr.views.update_application app.id 5 %}">Mark as Complete</a>,&nbsp;
+{% endifequal %}
+{% endif %}
+{% endifnotequal %}
 </p>
 
 {% if audit %}