Mercurial > genshi > mirror
changeset 388:31dc3d18b39e stable-0.3.x
0.3.x branch: add unit test for `Undefined` checks in template expressions.
author | cmlenz |
---|---|
date | Mon, 11 Dec 2006 12:06:28 +0000 |
parents | a52452a65cd7 |
children | ccf00b09972c |
files | genshi/eval.py |
diffstat | 1 files changed, 9 insertions(+), 0 deletions(-) [+] |
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--- a/genshi/eval.py +++ b/genshi/eval.py @@ -61,6 +61,15 @@ >>> data = dict(items=[1, 2, 3]) >>> Expression('len(items)').evaluate(data) 3 + + Undefined variables can be accessed in expressions, and evaluate to a + non-truth value for tests. To check whether a particular variable is + defined, its type can be compared to the special builtin class `Undefined`: + + >>> Expression('foo').evaluate({}) + undefined + >>> Expression('type(foo) is Undefined').evaluate({}) + True """ __slots__ = ['source', 'code']