apl: tokenizer + 46 tests (Phase 1, step 1)

Unicode-aware byte scanner using starts-with?/consume! for multi-byte
APL glyphs. Handles numbers (¯-negative), string literals, identifiers
(⎕ system names), all APL function/operator glyphs, :Keywords,
comments ⍝, diamond ⋄, assignment ←.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

lib/apl/tokenizer.sx

@@ -0,0 +1,168 @@
+(define apl-glyph-set
+  (list "+" "-" "×" "÷" "*" "⍟" "⌈" "⌊" "|" "!" "?" "○" "~" "<" "≤" "=" "≥" ">" "≠"
+        "∊" "∧" "∨" "⍱" "⍲" "," "⍪" "⍴" "⌽" "⊖" "⍉" "↑" "↓" "⊂" "⊃" "⊆"
+        "∪" "∩" "⍳" "⍸" "⌷" "⍋" "⍒" "⊥" "⊤" "⊣" "⊢" "⍎" "⍕"
+        "⍺" "⍵" "∇" "/" "\\" "¨" "⍨" "∘" "." "⍣" "⍤" "⍥" "@" "¯"))
+
+(define apl-glyph?
+  (fn (ch)
+    (some (fn (g) (= g ch)) apl-glyph-set)))
+
+(define apl-digit?
+  (fn (ch)
+    (and (string? ch) (>= ch "0") (<= ch "9"))))
+
+(define apl-alpha?
+  (fn (ch)
+    (and (string? ch)
+         (or (and (>= ch "a") (<= ch "z"))
+             (and (>= ch "A") (<= ch "Z"))
+             (= ch "_")))))
+
+(define apl-tokenize
+  (fn (source)
+    (let ((pos 0)
+          (src-len (len source))
+          (tokens (list)))
+
+      (define tok-push!
+        (fn (type value)
+          (append! tokens {:type type :value value})))
+
+      (define cur-sw?
+        (fn (ch)
+          (and (< pos src-len) (starts-with? (slice source pos) ch))))
+
+      (define cur-byte
+        (fn ()
+          (if (< pos src-len) (nth source pos) nil)))
+
+      (define advance!
+        (fn ()
+          (set! pos (+ pos 1))))
+
+      (define consume!
+        (fn (ch)
+          (set! pos (+ pos (len ch)))))
+
+      (define find-glyph
+        (fn ()
+          (let ((rem (slice source pos)))
+            (let ((matches (filter (fn (g) (starts-with? rem g)) apl-glyph-set)))
+              (if (> (len matches) 0) (first matches) nil)))))
+
+      (define read-digits!
+        (fn (acc)
+          (if (and (< pos src-len) (apl-digit? (cur-byte)))
+            (let ((ch (cur-byte)))
+              (begin
+                (advance!)
+                (read-digits! (str acc ch))))
+            acc)))
+
+      (define read-ident-cont!
+        (fn ()
+          (when (and (< pos src-len)
+                     (let ((ch (cur-byte)))
+                       (or (apl-alpha? ch) (apl-digit? ch))))
+            (begin
+              (advance!)
+              (read-ident-cont!)))))
+
+      (define read-string!
+        (fn (acc)
+          (cond
+            ((>= pos src-len) acc)
+            ((cur-sw? "'")
+             (if (and (< (+ pos 1) src-len) (cur-sw? "'"))
+               (begin
+                 (advance!)
+                 (advance!)
+                 (read-string! (str acc "'")))
+               (begin (advance!) acc)))
+            (true
+             (let ((ch (cur-byte)))
+               (begin
+                 (advance!)
+                 (read-string! (str acc ch))))))))
+
+      (define skip-line!
+        (fn ()
+          (when (and (< pos src-len) (not (cur-sw? "\n")))
+            (begin
+              (advance!)
+              (skip-line!)))))
+
+      (define scan!
+        (fn ()
+          (when (< pos src-len)
+            (let ((ch (cur-byte)))
+              (cond
+                ((or (= ch " ") (= ch "\t") (= ch "\r"))
+                 (begin (advance!) (scan!)))
+                ((= ch "\n")
+                 (begin (advance!) (tok-push! :newline nil) (scan!)))
+                ((cur-sw? "⍝")
+                 (begin (skip-line!) (scan!)))
+                ((cur-sw? "⋄")
+                 (begin (consume! "⋄") (tok-push! :diamond nil) (scan!)))
+                ((= ch "(")
+                 (begin (advance!) (tok-push! :lparen nil) (scan!)))
+                ((= ch ")")
+                 (begin (advance!) (tok-push! :rparen nil) (scan!)))
+                ((= ch "[")
+                 (begin (advance!) (tok-push! :lbracket nil) (scan!)))
+                ((= ch "]")
+                 (begin (advance!) (tok-push! :rbracket nil) (scan!)))
+                ((= ch "{")
+                 (begin (advance!) (tok-push! :lbrace nil) (scan!)))
+                ((= ch "}")
+                 (begin (advance!) (tok-push! :rbrace nil) (scan!)))
+                ((= ch ";")
+                 (begin (advance!) (tok-push! :semi nil) (scan!)))
+                ((cur-sw? "←")
+                 (begin (consume! "←") (tok-push! :assign nil) (scan!)))
+                ((= ch ":")
+                 (let ((start pos))
+                   (begin
+                     (advance!)
+                     (if (and (< pos src-len) (apl-alpha? (cur-byte)))
+                       (begin
+                         (read-ident-cont!)
+                         (tok-push! :keyword (slice source start pos)))
+                       (tok-push! :colon nil))
+                     (scan!))))
+                ((and (cur-sw? "¯")
+                      (< (+ pos (len "¯")) src-len)
+                      (apl-digit? (nth source (+ pos (len "¯")))))
+                 (begin
+                   (consume! "¯")
+                   (let ((digits (read-digits! "")))
+                     (tok-push! :num (- 0 (parse-int digits 0))))
+                   (scan!)))
+                ((apl-digit? ch)
+                 (begin
+                   (let ((digits (read-digits! "")))
+                     (tok-push! :num (parse-int digits 0)))
+                   (scan!)))
+                ((= ch "'")
+                 (begin
+                   (advance!)
+                   (let ((s (read-string! "")))
+                     (tok-push! :str s))
+                   (scan!)))
+                ((or (apl-alpha? ch) (cur-sw? "⎕"))
+                 (let ((start pos))
+                   (begin
+                     (if (cur-sw? "⎕") (consume! "⎕") (advance!))
+                     (read-ident-cont!)
+                     (tok-push! :name (slice source start pos))
+                     (scan!))))
+                (true
+                 (let ((g (find-glyph)))
+                   (if g
+                     (begin (consume! g) (tok-push! :glyph g) (scan!))
+                     (begin (advance!) (scan!))))))))))
+
+      (scan!)
+      tokens)))