forth: CHAR/[CHAR]/KEY/ACCEPT (+7; Hayes 174/590)

plans/forth-on-sx.md

@@ -79,7 +79,7 @@ Representation:
 
 ### Phase 4 — strings + more Core
 - [x] `S"`, `C"`, `."`, `TYPE`, `COUNT`, `CMOVE`, `FILL`, `BLANK`
-- [ ] `CHAR`, `[CHAR]`, `KEY`, `ACCEPT`
+- [x] `CHAR`, `[CHAR]`, `KEY`, `ACCEPT`
 - [ ] `BASE` manipulation: `DECIMAL`, `HEX`
 - [ ] `DEPTH`, `SP@`, `SP!`
 - [ ] Drive Hayes Core pass-rate up
@@ -99,6 +99,15 @@ Representation:
 
 _Newest first._
 
+- **Phase 4 — `CHAR`/`[CHAR]`/`KEY`/`ACCEPT` (+7 / Hayes 168→174).**
+  `CHAR` parses the next token and pushes the first-char code. `[CHAR]`
+  is IMMEDIATE: in compile mode it embeds the code as a compiled push
+  op, in interpret mode it pushes inline. `KEY`/`ACCEPT` read from an
+  optional `state.keybuf` string — empty buffer makes `KEY` raise
+  `"no input available"` (matches ANS when stdin is closed) and
+  `ACCEPT` returns `0`. Enough for Hayes to get past CHAR-gated
+  clusters; real interactive IO lands later.
+
 - **Phase 4 — strings: `S"`/`C"`/`."`/`TYPE`/`COUNT`/`CMOVE`/`CMOVE>`/`MOVE`/`FILL`/`BLANK`/`C@`/`C!`/`CHAR+`/`CHARS` (+16 / Hayes 165→168).**
   Added a byte-addressable memory model to state: `mem` (dict keyed by
   stringified address → integer byte) and `here` (next-free integer