Fett

Overview

Example

import fett

fett.Template('''{{ for customer in customers }}
{{ if i even }}
Even: {{ customer.name }}
{{ else }}
Odd: {{ customer.name }}
{{ end }}
{{ else }}
No customers :(
{{ end }}''').render({'customers': [
    {'name': 'Bob'},
    {'name': 'Elvis'},
    {'name': 'Judy'}
]})

Syntax

Tag Format	Description
{{ <expression> }}	Substitutions
{{ `foo` <expression> }}	Substitutions
{{ format <name> }}	Metaformatting
{{ if <expression> }}	Conditionals
{{ for <name> in <expression> }}	Loops
{{ else }}
{{ end }}	Block termination
{{ # <comment> }}	Comments

Spaces between tag opening/closing delimiters are optional.

Expressions

An expression is given for Substitutions, Conditionals, and Loops.

Expressions take the following form:

<name>[.<subfield>...] [<filter> [<filter2>...]]

Instead of specifying a field path, you can start an expression using a string literal:

<literal> [<filter> [<filter2>...]]

You can use filters to modify a single value in simple ways. For example, the loop iteration counter i counts from 0, but users often wish to count from 1. You can obtain a count-from-1 value with the expression i inc.

The full list of filters:

Filter Name	Effect
car	Returns the first element of a list.
cdr	Returns all but the first element of a list.
dec	Decrements a value representable as an integer by one.
even	Returns true iff its input is representable as an even integer.
escape	Encodes &, <, >, ", and ' characters with HTML entities.
inc	Increments a value representable as an integer by one.
len	Returns the length of a list.
not	Returns the inverse of a boolean.
odd	Returns true iff its input is representable as an odd integer.
negative	Returns true iff its input is representable as an integer < 0.
positive	Returns true iff its input is representable as an integer > 0.
split	Splits a value into a list by whitespace.
strip	Returns the input string with surrounding whitespace removed.
striptags	Remove HTML tags from a value.
timesNegOne	Returns int(input) * -1
zero	Returns true iff the input is zero

Filter Name	Effect
upperCase	Returns a Unicode-aware uppercase version of the input.
lowerCase	Returns a Unicode-aware lowercase version of the input.

Filter Name	Effect
add(n)	Increments a value representable as an integer by n.
minus(n)	Decrements a value representable as an integer by n.
equal(value)	Returns true iff a value equals the given value.
lessThan(n)	Returns true iff n < the given value.
lessThanOrEqual(n)	Returns true iff n <= the given value.
greaterThan(n)	Returns true iff n > the given value.
greaterThanOrEqual(n)	Returns true iff n >= the given value.

Substitutions

Metaformatting

Conditionals

Loops

Comments