Additionally, it will probably be confusing that it is called a t-string but it is actually a constructor for a Template object and not string at all. I would rather see a new special term `template` than this.

The single letter f or t does make it unnatural to read, but if it were sql"..." or html"...", I think that would help with that.

Should have been a keyword.

    a = template "foo {bar}"

As should raw and format.