Template Strings (T-Strings)¶

Template strings (t-strings) provide structured string interpolation, producing a Template object instead of a plain string. Inspired by Python PEP 750.

Syntax¶

T-strings use the t prefix, analogous to f-strings:

name = "Alice"
greeting = t"Hello {name}"
print(greeting)  # Hello Alice

T-strings support the same interpolation syntax as f-strings — any expression can appear inside {}:

x = 10
result = t"Value: {x * 2}"

Template Type¶

T-strings produce a value of type Template. You can annotate variables explicitly:

name = "Alice"
greeting: Template = t"Hi {name}"
print(greeting)

Triple-Quoted T-Strings¶

Multi-line t-strings use triple quotes:

name = "World"
msg = t"""
Hello {name}
Welcome!
"""

T-String Concatenation¶

T-strings can be concatenated with the + operator:

first = t"Hello "
second = t"World"
combined = first + second

Relationship to F-Strings¶

Feature	F-String (`f"..."`)	T-String (`t"..."`)
Prefix	`f`	`t`
Result type	`str`	`Template`
Interpolation	`{expr}`	`{expr}`
Use case	String formatting	Structured interpolation

Both f-strings and t-strings share the same interpolation part structure internally (FStringPart), but t-strings preserve interpolation structure in the resulting Template object rather than eagerly producing a string.

Generated C¶

T-strings are lowered similarly to f-strings, producing a Template value:

name = "world"
result = t"Hello {name}"

Implementation - ✅ Implemented — TStringLiteral AST node, lexer support for t"..." / t'...' / t"""...""" prefixes - Produces Template type (not str) - Shares interpolation infrastructure with f-strings