SmartFormat for Python

SmartFormat is a powerful string formatter which was introduced on the .NET community. Especially the formatter is helpful for making an internationalization system. You can make a text template for multiple pluralizable words for the whole of the natural languages.

This library provides a Python string formatter which imitates SmartFormat.NET based on string.Formatter in the standard library and Babel for internationalization.

Currently, this library doesn't implement the full specification yet. Because the localization models in Babel and .NET have some differences with each other.

Usage

Install via PyPI first:

$ pip install smartformat

Then use like a string.Formatter:

>>> from smartformat import SmartFormatter
>>> smart = SmartFormatter('en_US')
>>> text = u'{gender:c(male|female):He|She} got {num_items:an item|{} items}.'
>>> smart.format(text, gender=Gender.male, num_items=1)
He got an item.
>>> smart.format(text, gender=Gender.female, num_items=42)
She got 42 items.

.NET String.Format Specs

• {:n} - Number
• {:n3} - Number with specific fractional precision
• {:p} - Percent
• {:p3} - Percent with specific fractional precision
• {:c} - Currency (JPY symbol is different with .NET)
• {:c3} - Currency with specific fractional precision
• {:-c} - Negative currency
• {:d}
• {:e}
• {:f}
• {:g}
• {:r}
• {:x}

SmartFormat Specs

• Nested Placeholder
• Getting value by attribute
• Plural Extension: {:an item|{} items}
• Choose Extension: {:choose(male|female):He|She}
• Conditional Extension - Originally deprecated, we won't implement it.
• List Extension: {:{}|, |, and }
• Time Extension

Custom Extension

To make your own extension, define a function which takes (formatter, value, name, option, format) parameters and decorate with @smartformat.extension:

import smartformat

@smartformat.extension(['hello'])
def hello(formatter, value, name, option, format):
    return 'HELLO ' + (option if value else format)

Register any extension to a SmartFormatter instance:

>>> smart = SmartFormatter('en_US', [hello])
>>> smart.format(u'{:hello(world):earth}', True)
HELLO world
>>> smart.format(u'{:hello(world):earth}', False)
HELLO earth

An extension can be dispatched without name implicitly. If you want to do so, set '' as a one of the extension names. Implicit extension may skip to format some inputs by returning None:

@smartformat.extension(['foo', ''])
def foo(formatter, value, name, option, format):
    if value:
        return 'foo'
    else:
        return
@smartformat.extension(['bar', ''])
def bar(formatter, value, name, option, format):
    return 'bar'

>>> smart = SmartFormatter('en_US', [foo, bar])
>>> smart.format(u'{:}', True)
foo
>>> smart.format(u'{:}', False)
bar

The name of a module for SmartFormat extensions should starts with smartformat_. They can be imported under smartformat.ext. For example, import smartformat.ext.hello will import the smartformat_hello module actually. Just like flask.ext!

Licensing

Written or designed by Heungsub Lee at What! Studio in Nexon, and distributed under the BSD 3-Clause license.