forth: String word set COMPARE/SEARCH/SLITERAL (+9)

lib/forth/compiler.sx

@@ -793,6 +793,53 @@
         (let
           ((w (forth-pop s)))
           (forth-push s (or (get w "body-addr") 0)))))
+    (forth-def-prim-imm!
+      state
+      "SLITERAL"
+      (fn
+        (s)
+        (let
+          ((u (forth-pop s)) (c-addr (forth-pop s)))
+          (let
+            ((content (forth-mem-read-string s c-addr u)))
+            (let
+              ((new-addr (forth-alloc-bytes! s u)))
+              (forth-mem-write-string! s new-addr content)
+              (forth-def-append! s (fn (ss) (forth-push ss new-addr)))
+              (forth-def-append! s (fn (ss) (forth-push ss u))))))))
+    (forth-def-prim!
+      state
+      "COMPARE"
+      (fn
+        (s)
+        (let
+          ((u2 (forth-pop s))
+            (a2 (forth-pop s))
+            (u1 (forth-pop s))
+            (a1 (forth-pop s)))
+          (forth-push s (forth-compare-bytes-loop s a1 u1 a2 u2 0)))))
+    (forth-def-prim!
+      state
+      "SEARCH"
+      (fn
+        (s)
+        (let
+          ((u2 (forth-pop s))
+            (a2 (forth-pop s))
+            (u1 (forth-pop s))
+            (a1 (forth-pop s)))
+          (let
+            ((idx (forth-search-bytes s a1 u1 a2 u2 0)))
+            (if
+              (< idx 0)
+              (begin
+                (forth-push s a1)
+                (forth-push s u1)
+                (forth-push s 0))
+              (begin
+                (forth-push s (+ a1 idx))
+                (forth-push s (- u1 idx))
+                (forth-push s -1)))))))
     (forth-def-prim! state "R/O" (fn (s) (forth-push s 0)))
     (forth-def-prim! state "W/O" (fn (s) (forth-push s 1)))
     (forth-def-prim! state "R/W" (fn (s) (forth-push s 2)))

lib/forth/runtime.sx

@@ -381,6 +381,46 @@
             (dict-set! state "hold" (cons ch (get state "hold")))
             (forth-double-push-u state rest)))))))
 
+(define
+  forth-compare-bytes-loop
+  (fn
+    (state a1 u1 a2 u2 i)
+    (cond
+      ((and (= i u1) (= i u2)) 0)
+      ((= i u1) -1)
+      ((= i u2) 1)
+      (else
+        (let
+          ((b1 (forth-mem-read state (+ a1 i)))
+            (b2 (forth-mem-read state (+ a2 i))))
+          (cond
+            ((< b1 b2) -1)
+            ((> b1 b2) 1)
+            (else (forth-compare-bytes-loop state a1 u1 a2 u2 (+ i 1)))))))))
+
+(define
+  forth-match-at
+  (fn
+    (state a1 start a2 u2 j)
+    (cond
+      ((= j u2) true)
+      ((not
+        (=
+          (forth-mem-read state (+ a1 (+ start j)))
+          (forth-mem-read state (+ a2 j))))
+        false)
+      (else (forth-match-at state a1 start a2 u2 (+ j 1))))))
+
+(define
+  forth-search-bytes
+  (fn
+    (state a1 u1 a2 u2 i)
+    (cond
+      ((= u2 0) 0)
+      ((> (+ i u2) u1) -1)
+      ((forth-match-at state a1 i a2 u2 0) i)
+      (else (forth-search-bytes state a1 u1 a2 u2 (+ i 1))))))
+
 (define
   forth-pic-S-loop
   (fn

lib/forth/scoreboard.json

@@ -1,6 +1,6 @@
 {
   "source": "gerryjackson/forth2012-test-suite src/core.fr",
-  "generated_at": "2026-04-25T02:24:33Z",
+  "generated_at": "2026-04-25T02:53:26Z",
   "chunks_available": 638,
   "chunks_fed": 638,
   "total": 638,

lib/forth/scoreboard.md

@@ -11,7 +11,7 @@
 | percent           | 76% |
 
 - **Source**: `gerryjackson/forth2012-test-suite` `src/core.fr`
-- **Generated**: 2026-04-25T02:24:33Z
+- **Generated**: 2026-04-25T02:53:26Z
 - **Note**: completed
 
 A "chunk" is any preprocessed segment ending at a `}T` (every Hayes test

lib/forth/tests/test-phase5.sx

@@ -268,6 +268,38 @@
       "S\" /tmp/nope.fxf\" R/O OPEN-FILE SWAP DROP 0 ="
       0)))
 
+(define
+  forth-p5-string-tests
+  (fn
+    ()
+    (forth-p5-check-top "COMPARE equal" "S\" ABC\" S\" ABC\" COMPARE" 0)
+    (forth-p5-check-top "COMPARE less" "S\" ABC\" S\" ABD\" COMPARE" -1)
+    (forth-p5-check-top "COMPARE greater" "S\" ABD\" S\" ABC\" COMPARE" 1)
+    (forth-p5-check-top
+      "COMPARE prefix less"
+      "S\" AB\" S\" ABC\" COMPARE"
+      -1)
+    (forth-p5-check-top
+      "COMPARE prefix greater"
+      "S\" ABC\" S\" AB\" COMPARE"
+      1)
+    (forth-p5-check-top
+      "SEARCH found flag"
+      "S\" HELLO WORLD\" S\" WORLD\" SEARCH"
+      -1)
+    (forth-p5-check-top
+      "SEARCH not found flag"
+      "S\" HELLO\" S\" XYZ\" SEARCH"
+      0)
+    (forth-p5-check-top
+      "SEARCH empty needle flag"
+      "S\" HELLO\" S\" \" SEARCH"
+      -1)
+    (forth-p5-check-top
+      "SLITERAL via [ S\" ... \" ]"
+      ": A [ S\" HI\" ] SLITERAL ; A SWAP DROP"
+      2)))
+
 (define
   forth-p4-check-output-passthrough
   (fn
@@ -291,6 +323,7 @@
     (forth-p5-state-tests)
     (forth-p5-misc-tests)
     (forth-p5-fa-tests)
+    (forth-p5-string-tests)
     (dict
       "passed"
       forth-p5-passed

plans/forth-on-sx.md

@@ -94,7 +94,7 @@ Representation:
 - [x] Source/state: `EVALUATE`, `STATE`, `[`, `]` (`SOURCE`/`>IN` stubbed; tokenized input means the exact byte/offset semantics aren't useful here)
 - [x] Misc Core: `WITHIN`, `MAX`/`MIN` (already), `ABORT`, `ABORT"`, `EXIT`, `UNLOOP`
 - [x] File Access word set (in-memory — `read-file` is not reachable from the epoch eval env)
-- [ ] String word set (`SLITERAL`, `COMPARE`, `SEARCH`)
+- [x] String word set (`SLITERAL`, `COMPARE`, `SEARCH`)
 - [ ] Target: 100% Hayes Core
 
 ### Phase 6 — speed
@@ -106,6 +106,17 @@ Representation:
 
 _Newest first._
 
+- **Phase 5 — String word set `COMPARE`/`SEARCH`/`SLITERAL` (+9).**
+  `COMPARE` walks bytes via the new `forth-compare-bytes-loop`,
+  returning -1/0/1 with standard prefix semantics (shorter string
+  compares less than its extension). `SEARCH` scans the haystack
+  with a helper `forth-search-bytes` and `forth-match-at`, returning
+  the tail after the first match or the original string with flag=0.
+  Empty needle returns at offset 0 with flag=-1 per ANS. `SLITERAL`
+  is IMMEDIATE: pops `(c-addr u)` at compile time, copies the bytes
+  into a fresh allocation, and emits the two pushes so the compiled
+  word yields the interned string at runtime.
+
 - **Phase 5 — File Access word set (in-memory backing; +4).**
   `OPEN-FILE`/`CREATE-FILE`/`CLOSE-FILE`/`READ-FILE`/`WRITE-FILE`/
   `FILE-POSITION`/`FILE-SIZE`/`REPOSITION-FILE`/`DELETE-FILE` plus