Phase 7h: string slicing s[a..b] (retire substr)

`s[a..b]` is a fresh substring of the bytes [a, b) — the modern, end-based form
of the C-style `substr(s, start, count)`:

  substr(src, start, i - start)   -> src[start..i]
  substr(t, 2, len(t) - 2)        -> t[2..len(t)]
  substr(src, i, 2)               -> src[i..i + 2]

Mechanics: a new E_SLICE postfix (`base[lo..hi]`, distinct from `base[i]`
indexing) lowers to a @fn_str_slice prelude (malloc + copy + terminate), emitted
once into any program that slices. Two reseeds: add the syntax + prelude, then
migrate the 22 substr calls and delete substr. The migrator recognises the
common `count == end - start` shape and emits the clean `s[start..end]` rather
than `s[start..start + (end - start)]`.

examples/strings.ludic gains slicing (now prints 1..9). Reseeded (22673 lines);
C-free fixpoint holds; goldens identical; 18/18; vocab + doc-fences clean.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
This commit is contained in:
Orkun ÇAKILKAYA 2026-08-28 01:35:24 +03:00
parent 0efa06dca2
commit 1b9789630a
14 changed files with 4049 additions and 3914 deletions

View file

@ -3,13 +3,6 @@
# byte buffers reached with peek8/poke8.
# a fresh NUL-terminated copy of src[start .. start+n]
fn substr(src: ptr, start: int, n: int) -> ptr {
let b = mem_alloc(n + 1)
var i = 0
while i < n { poke8(b, i, peek8(src, start + i)); i = i + 1 }
poke8(b, n, 0)
return b
}
fn char_is_digit(c: int) -> bool { return c >= 48 and c <= 57 }
fn char_is_alpha(c: int) -> bool {