pyokagan/tempy

Simple Python templates

tempy - Simple Python templates

tempy is a tiny (~200 SLOC) python template engine for text processing tasks. It exposes the full functionality of Python in your templates by passing everything to compile() and eval() with minimal processing.

Requirements

• Python 2.6+ (2.6, 2.7, 3.2, 3.3, 3.4)

Usage

The function render compiles and renders a template. Any keyword arguments passed to it will be used as local variables:

>>> import tempy
>>> tempy.render('Hello {{name}}!', name='World')
'Hello World!'

The function compile compiles a template into a function for later use:

>>> import tempy
>>> func = tempy.compile('Hello {{name}}!', args=['name'],
...                      defaults=['Bill'])
>>> func('World')
'Hello World!'
>>> func()
'Hello Bill!'

The resulting function signature can be controlled using the arguments args, varargs, varkw and defaults. args is a list of argument names, varargs and varkw are the names of the * and ** arguments, and defaults is a list if default argument values. If defaults has n elements, they correspond to the last n elements listed in args.

Template Syntax

Inline Expressions

Inline expressions are of the form {{...}}. Any python expression that can be evaluated using eval is allowed:

>>> tempy.render('{{ 1 + 1 }}')
'2'

Control Structures

The syntax for inline expressions can also be used for control structures such as if, for, def and so forth. However, they have to be explictly closed using the special keyword end:

>>> tempy.render('{{for x in range(10):}}{{x}} {{end}}')
'0 1 2 3 4 5 6 7 8 9 '

Note, though, that special keywords like continue and pass are only valid in code blocks:

>>> tempy.render('''{{for x in range(10):-}}
... <%- if x == 2: continue -%>
... {{x}} {{end}}''')
'0 1 3 4 5 6 7 8 9 '

Code Blocks

Blocks of python code embedded within <%...%> will be executed:

>>> tempy.render('<% x = 42 %>x is {{x}}')
'x is 42'

Note that python indentation rules apply within code blocks:

>>> tempy.render('''<%
... out = []
... for x in range(10):
...   out.append(str(x))
... %>{{' '.join(out)}}''')
'0 1 2 3 4 5 6 7 8 9'

Escaping

To escape a code block or inline statement, place a backslash character (\) before the start of a code block or inline statement token. For example:

>>> tempy.render(r'\<%x = 42%>')
'<%x = 42%>'

Whitespace Control

Placing a minus sign (-) at the start or end of a code block or inline statement will remove all whitespace before or after that block respectively:

>>> tempy.render('{{if True:-}}  42  {{end}}')
'42  '
>>> tempy.render('{{if True:}}  42  {{-end}}')
'  42'
>>> tempy.render('{{if True:-}}  42  {{-end}}')
'42'

License

MIT License