diff options
| -rw-r--r-- | coverage/templite.py | 147 | ||||
| -rw-r--r-- | test/test_templite.py | 59 |
2 files changed, 144 insertions, 62 deletions
diff --git a/coverage/templite.py b/coverage/templite.py index 3b2efebd..c0c1b1da 100644 --- a/coverage/templite.py +++ b/coverage/templite.py @@ -1,10 +1,5 @@ """A simple Python template renderer, for a nano-subset of Django syntax.""" -# Started from http://blog.ianbicking.org/templating-via-dict-wrappers.html -# and http://jtauber.com/2006/05/templates.html -# and http://code.activestate.com/recipes/496730/ -# Coincidentally named the same as http://code.activestate.com/recipes/496702/ - import re class Templite(object): @@ -14,10 +9,14 @@ class Templite(object): {{var.modifer.modifier|filter|filter}} - and loops:: + loops:: {% for var in list %}...{% endfor %} + and ifs:: + + {% if var %}...{% endif %} + Comments are within curly-hash markers:: {# This will be ignored #} @@ -33,11 +32,47 @@ class Templite(object): These are good for filters and global values. """ - self.loops = [] - self.text = self._prepare(text) + self.text = text self.context = {} for context in contexts: self.context.update(context) + + # Split the text to form a list of tokens. + toks = re.split( + r"(?s)({{.*?}}|{%.*?%}|{#.*?#})", text + ) + + # Parse the tokens into a nested list of operations. + stack = [] + ops = [] + for tok in toks: + if tok.startswith('{{'): + ops.append(('var', tok[2:-2].strip())) + elif tok.startswith('{#'): + continue + elif tok.startswith('{%'): + words = tok[2:-2].strip().split() + if words[0] == 'if': + if_ops = [] + assert len(words) == 2 + ops.append(('if', (words[1], if_ops))) + stack.append(ops) + ops = if_ops + elif words[0] == 'for': + assert len(words) == 4 and words[2] == 'in' + for_ops = [] + ops.append(('for', (words[1], words[3], for_ops))) + stack.append(ops) + ops = for_ops + elif words[0].startswith('end'): + ops = stack.pop() + assert ops[-1][0] == words[0][3:] + else: + ops.append(('lit', tok)) + + assert not stack + + self.ops = ops def render(self, context=None): """Render this template by applying it to `context`. @@ -50,63 +85,55 @@ class Templite(object): if context: ctx.update(context) - ctxaccess = _ContextAccess(ctx) - - # Render the loops. - for iloop, (loopvar, listvar, loopbody) in enumerate(self.loops): - result = "" - for listval in ctxaccess[listvar]: - ctx[loopvar] = listval - result += loopbody % ctxaccess - ctx["loop:%d" % iloop] = result - - # Render the final template. - return self.text % ctxaccess - - def _prepare(self, text): - """Convert Django-style data references into Python-native ones.""" - # Remove comments. - text = re.sub(r"(?s){#.*?#}", "", text) - # Pull out loops. - text = re.sub( - r"(?s){% for ([a-z0-9_]+) in ([a-z0-9_.|]+) %}(.*?){% endfor %}", - self._loop_prepare, text - ) - # Protect actual percent signs in the text. - text = text.replace("%", "%%") - # Convert {{foo}} into %(foo)s - text = re.sub(r"{{(.+?)}}", r"%(\1)s", text) - return text + engine = _TempliteEngine(ctx) + engine.execute(self.ops) + return engine.result - def _loop_prepare(self, match): - """Prepare a loop body for `_prepare`.""" - nloop = len(self.loops) - # Append (loopvar, listvar, loopbody) to self.loops - loopvar, listvar, loopbody = match.groups() - loopbody = self._prepare(loopbody) - self.loops.append((loopvar, listvar, loopbody)) - return "{{loop:%d}}" % nloop - -class _ContextAccess(object): - """A mediator for a context. - - Implements __getitem__ on a context for Templite, so that string formatting - references can pull data from the context. - - """ +class _TempliteEngine(object): + """Executes Templite objects to produce strings.""" def __init__(self, context): self.context = context + self.result = "" - def __getitem__(self, key): - if "|" in key: - pipes = key.split("|") - value = self[pipes[0]] + def execute(self, ops): + """Execute `ops` in the engine. + + Called recursively for the bodies of if's and loops. + + """ + for op, args in ops: + if op == 'lit': + self.result += args + elif op == 'var': + self.result += str(self.evaluate(args)) + elif op == 'if': + expr, body = args + if self.evaluate(expr): + self.execute(body) + elif op == 'for': + var, lis, body = args + vals = self.evaluate(lis) + for val in vals: + self.context[var] = val + self.execute(body) + else: + self.result += "???" + + def evaluate(self, expr): + """Evaluate an expression. + + `expr` can have pipes and dots to indicate data access and filtering. + + """ + if "|" in expr: + pipes = expr.split("|") + value = self.evaluate(pipes[0]) for func in pipes[1:]: - value = self[func](value) - elif "." in key: - dots = key.split('.') - value = self[dots[0]] + value = self.evaluate(func)(value) + elif "." in expr: + dots = expr.split('.') + value = self.evaluate(dots[0]) for dot in dots[1:]: try: value = getattr(value, dot) @@ -115,5 +142,5 @@ class _ContextAccess(object): if hasattr(value, '__call__'): value = value() else: - value = self.context[key] + value = self.context[expr] return value diff --git a/test/test_templite.py b/test/test_templite.py index 4c7545bf..8cb25865 100644 --- a/test/test_templite.py +++ b/test/test_templite.py @@ -130,12 +130,67 @@ class TempliteTest(unittest.TestCase): # Single-line comments work: self.try_render( "Hello, {# Name goes here: #}{{name}}!", - {'name':'Ned'}, "Hello, Ned!") + {'name':'Ned'}, "Hello, Ned!" + ) # and so do multi-line comments: self.try_render( "Hello, {# Name\ngoes\nhere: #}{{name}}!", - {'name':'Ned'}, "Hello, Ned!") + {'name':'Ned'}, "Hello, Ned!" + ) + def test_if(self): + self.try_render( + "Hi, {% if ned %}NED{% endif %}{% if ben %}BEN{% endif %}!", + {'ned': 1, 'ben': 0}, + "Hi, NED!" + ) + self.try_render( + "Hi, {% if ned %}NED{% endif %}{% if ben %}BEN{% endif %}!", + {'ned': 0, 'ben': 1}, + "Hi, BEN!" + ) + self.try_render( + "Hi, {% if ned %}NED{% if ben %}BEN{% endif %}{% endif %}!", + {'ned': 0, 'ben': 0}, + "Hi, !" + ) + self.try_render( + "Hi, {% if ned %}NED{% if ben %}BEN{% endif %}{% endif %}!", + {'ned': 1, 'ben': 0}, + "Hi, NED!" + ) + self.try_render( + "Hi, {% if ned %}NED{% if ben %}BEN{% endif %}{% endif %}!", + {'ned': 1, 'ben': 1}, + "Hi, NEDBEN!" + ) + def test_loop_if(self): + self.try_render( + "@{% for n in nums %}{% if n %}Z{% endif %}{{n}}{% endfor %}!", + {'nums': [0,1,2]}, + "@0Z1Z2!" + ) + self.try_render( + "X{%if nums%}@{% for n in nums %}{{n}}{% endfor %}{%endif%}!", + {'nums': [0,1,2]}, + "X@012!" + ) + self.try_render( + "X{%if nums%}@{% for n in nums %}{{n}}{% endfor %}{%endif%}!", + {'nums': []}, + "X!" + ) + + def test_nested_loops(self): + self.try_render( + "@{% for n in nums %}" + "{% for a in abc %}{{a}}{{n}}{% endfor %}" + "{% endfor %}!", + {'nums': [0,1,2], 'abc': ['a', 'b', 'c']}, + "@a0b0c0a1b1c1a2b2c2!" + ) + + if __name__ == '__main__': unittest.main() |