tstring-util 0.3

Utilities for tstring

tstring-util

Utlities for Python 3.14 t-string.

Python 3.14 supports creating objects of type string.templatelib.Template by prefixing with a "t".

lazy rendering

render(string.templatelib.Template)->str

Provides ability to write t-string with function calls with deferred evaluation. Any callable marked !fn will consume as many following interpolations as its positional args, be invoked, and its stdout captured inline. Everything else is rendered in order.

Example

from tstring import render


def hello(name):
    print(f"hello {name}")

def test_lazy():
    who = 'bob'
    flavor = 'spicy'
    embedx = t'Call function {hello:!fn} {who} {flavor}'
    who = 'jane'
    r = render(embedx)
    assert r ==  "Call function hello jane spicy"

safe paths

path(string.templatelib.Template)->Path

Converts t-string to a path. If any interpolations have a NUL or path separator in them, ValueError is raised. A special case of the first character of the first element being a separator is permitted to make paths absolute.

Example

from tstring import path
config = '/etc'
p = path(t'{config}/systemd')
assert p.as_posix() ==  '/etc/systemd'

Invalid path:

 no_good = 'bob/carol'
 path(t'{no_good}')

raises ValueError Invalid character '/' in interpolation 'no_good'