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Diffstat (limited to 'docs/api.rst')
| -rw-r--r-- | docs/api.rst | 19 |
1 files changed, 11 insertions, 8 deletions
diff --git a/docs/api.rst b/docs/api.rst index 8b80749..b2db537 100644 --- a/docs/api.rst +++ b/docs/api.rst @@ -410,16 +410,19 @@ The Context .. automethod:: jinja2.runtime.Context.call(callable, \*args, \**kwargs) -.. admonition:: Implementation +The context is immutable, it prevents modifications, and if it is +modified somehow despite that those changes may not show up. For +performance, Jinja does not use the context as data storage for, only as +a primary data source. Variables that the template does not define are +looked up in the context, but variables the template does define are +stored locally. + +Instead of modifying the context directly, a function should return +a value that can be assigned to a variable within the template itself. - Context is immutable for the same reason Python's frame locals are - immutable inside functions. Both Jinja and Python are not using the - context / frame locals as data storage for variables but only as primary - data source. +.. code-block:: jinja - When a template accesses a variable the template does not define, Jinja - looks up the variable in the context, after that the variable is treated - as if it was defined in the template. + {% set comments = get_latest_comments() %} .. _loaders: |