"""

Template strings (t-strings) introduced in Python 3.14 (PEP 750).

T-strings look like f-strings but prefixed with 't' or 'T'. Instead of

immediately evaluating to a string, they evaluate to a Template object from

the string.templatelib module. This allows for deferred evaluation and

custom processing of the template parts and interpolations.

"""

import string.templatelib

def process_template(template: string.templatelib.Template) -> str:

"""Simple processor to demonstrate how Template objects work."""

# A Template object has 'strings' (tuple of static parts)

# and 'interpolations' (tuple of evaluated expression results)

# The number of strings is always len(interpolations) + 1

result = []

for i, s in enumerate(template.strings):

result.append(s)

if i < len(template.interpolations):

# Each item in interpolations is an object with a 'value' attribute

result.append(str(template.interpolations[i].value))

return "".join(result)

def main() -> None:

name = "World"

year = 2026

# 1. Basic t-string creation

# It evaluates to a string.templatelib.Template object

tpl = t"Hello {name}, welcome to {year}!"

assert isinstance(tpl, string.templatelib.Template)

# 2. Inspecting the template parts

# Static parts of the string

assert tpl.strings == ("Hello ", ", welcome to ", "!")

# Values of the expressions

assert tpl.interpolations[0].value == "World"

assert tpl.interpolations[1].value == 2026

# 3. Processing the template

# We can join them together manually or with a processor

processed = process_template(tpl)

assert processed == "Hello World, welcome to 2026!"

# 4. T-strings are great for safe processing (e.g. SQL, HTML)

# because they keep the structure separate from the data

user_input = "'; DROP TABLE users; --"

query_template = t"SELECT * FROM users WHERE name = {user_input}"

# In a real scenario, a processor would escape the values in query_template.interpolations

assert query_template.strings == ("SELECT * FROM users WHERE name = ", "")

assert query_template.interpolations[0].value == user_input

if __name__ == "__main__":

main()