PEP 750 – Template Strings (peps.python.org)

Article summary

PEP 750 introduces template strings to Python, a generalization of f-strings that allows for more flexible string processing. Template strings are defined using the 't' prefix and evaluate to a new type, Template, which provides access to the string and its interpolated values. This feature enables safety checks, web templating, and domain-specific languages. The Template type has attributes such as 'strings' and 'interpolations' that can be used to process the template.

Main themes

• Template Strings
• String Processing
• Python Enhancement Proposals
• Security
• Web Templating
• Domain-Specific Languages

What commenters say

• The introduction of template strings is a game-changer for applications involving HTML, SQL, or other languages embedded in Python programs.
• Template strings do not address the issue of deferred evaluation, which is a significant limitation.
• The use of lambda functions can help delay the evaluation of interpolations in template strings.
• Some commenters argue that the design of template strings feels backwards and that the name 'template strings' is a misnomer due to the lack of deferred evaluation.
• Others believe that the feature is useful and can help with tasks such as HTML escaping and SQL parameterization.
• The use of template strings is seen as a way to improve developer ergonomics and reduce the risk of injection attacks.
• Some commenters think that the feature is not necessary and that existing workarounds, such as using the format method, are sufficient.