datawinners/home/templatetags/evaluate_tag.py
from django import template
register = template.Library()
@register.tag(name="evaluate")
def do_evaluate(parser, token):
"""
tag usage {% evaluate object.textfield %}
"""
try:
tag_name, variable = token.split_contents()
except ValueError:
raise template.TemplateSyntaxError, "%r tag requires a single argument" % token.contents.split()[0]
return EvaluateNode(variable)
class EvaluateNode(template.Node):
def __init__(self, variable):
self.variable = template.Variable(variable)
def render(self, context):
try:
content = self.variable.resolve(context)
t = template.Template(content)
return t.render(context)
except template.VariableDoesNotExist, template.TemplateSyntaxError:
return 'Error rendering', self.variable