The readable way to build strings, as you noted `{a} {b}` beats `a + " " + b`.
A backtick string embeds any expression in `{…}` and desugars to the Phase-7c
`+` chain, wrapping each hole in `str(...)`:
`hello {name}, n={count + 1}`
== "hello " + name + ", n=" + str(count + 1)
- Lexer: a backtick captures its content raw as TK_INTERP.
- Parser: parse_interp splits literal runs from `{…}` holes (brace-depth aware,
`{{`/`}}` escape to literal braces), re-lexes each hole as a full expression
(save/restore toks/pi like an import), and folds it all into E_BIN(+) nodes —
so no new AST or runtime beyond the existing concat.
- str(x): a string passes through; int/bool/fixed convert via a small emitted
@fn_int_str prelude (digits from the end of a buffer, '-' for negatives),
emitted once into any program that uses it.
examples/strings.ludic gains interpolation cases (now prints 1..7); the smoke
covers it. Grammar + ludic_syntax.h tokenize backtick strings (holes highlighted
as embedded code). LANGUAGE.md documents it as the preferred form.
Reseeded (22530 lines); C-free fixpoint holds; goldens identical; 18/18; vocab +
doc-fences clean.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Orkuncakilkaya
ad63f09d53