Except it’s more if I have text following a variable.

Try this:

    STR.”x=\{x} y=\{y} z=\{z}.”

Compared to:

    “x=“ + x + “ y=“ + y + “ z=“ + z + “.”

A string template incurs an overhead of 3 characters per variable (“\“, “{“, and “}”) plus the leading “STR.”, which is 4 characters. Concatenation incurs an overhead of 4 non-whitespace characters per variable (`”+` and `+”`), and that’s ignoring whitespace. If you have more than 3-4 variables, string templates are shorter.

The concatenation example is less readable as well. Have I included whitespace to exactly match the string template example? It’s a little hard to tell at a glance because I have to distinguish what is code whitespace and what’s included in the string.

You may have a point for strings. But this is about guarantees for more convoluted expressions in other languages. If you include validating SQL being injection-free, this is waaay less verbose.

Also this is about enabling a _system_ of templating, and potentially letting the IDE treat it as such and warn you at compile-time. Small snippets tend to creep all over a codebase. Some use-case that this enables:

* HTML templating React-server-side-style: response.send(HTML_PART."""<div>\{name}</div>"""). Here both the HTML is validated, and the variable is escaped; at compile-time. How do you beat this?

* Query-building: businessFilterClause.add(WHERE_VALIDATE."""PRODUCT_MODEL IN \{authorizedModels}"""). And at compile-time or build-time having it validated against a database schema, and the compatibility of your types.