Evoque – managed eval-based freeform templating

Evoque is a full-featured generic text templating system for python using
a simple $-substitution syntax and providing support for flow control, nested
templates, overlays, inter-template addressing and invocation, cache management,
arbitrary python expressions, all python % operator formatting,
restricted execution, automatic cross-site scripting protection, advanced
encoding guessing algorithm, and more.

Allowing only python expressions and a managed evaluation namespace, Evoque
offers a surprising level of simplicity, versatility and performance.

Buzz

• Full-featured pure python templating engine / 992 SLOC
• Python 2.4, 2.5, 2.6 and 3.0
• Unicode
• Simplicity
• Restrictable execution / sandbox
• Data-driven template inheritance / runtime base template selection
• Open-ended source or target file formats
• Templates are managed via Collections in a Domain / cascading defaults
• Domain-wide template names / addressing
• Automatic input quoting / XSS protection
• Speed

Snapshot

$overlay{name=site_base}

$begin{table_row}
    $for{ col in row }
        <td>${col}</td>\
    $else
        <td class="empty" colspan="7">empty row</td>
    $rof
$end{table_row}

<table>
    $for{ i, row in enumerate(rows) }
        <tr$if{i%2} class="odd"$fi> #[ "odd" rows get a special style ]#
            $evoque{#table_row}
        </tr>
    $rof
</table>

$evoque{disclaimer, collection="legals"}

$test{% site_base="site.html", 
        rows=[("a", "b", 3.0, {"one":1}, "<escape-me/>", "i", "j")] %}

Usage from within a Python application

Templates are always part of a Collection in a Domain —
a Domain and a default Collection instance are always created,
be it explicitly or implicitly.

The preferred way to load/retrieve a Template is via a Domain instance;
the following code implicitly creates the default Collection instance:

domain = Domain("/home/user/templates")
t = domain.get_template("snap.html")
print t.evoque(vars())

It may sometimes be more convenient to instantiate directly;
the following code implicitly creates the Domain and the default
Collection instances:

t = Template("/home/user/templates", "snap.html")
print t.evoque(vars())

Basic benchmark

A basic benchmark, consisting of a small template
that does a variety of standard templating tasks such as looping,
calling nested and external sub-templates, escaping of data, etc.
For each run, time is averaged over 2000 renderings, and the
best time of 4 runs is retained.
All times are in ms.
What you should want is automatic quoting and less time.

(a) Restricted —
qpy 1.7 /
mako 0.2.4 /
genshi 0.5.1
offer no support for restricted execution or sandboxing
(b) manual quoting implies no qpy
(c) xml mode