Support reading long strings

src/waforth.wat

@@ -2758,14 +2758,16 @@
     (local $result i32)
     (local $tos i32)
     (local.tee $tos (global.get $tos))
+    (block $endLoop (param i32) (result i32)
+      (loop $loop (param i32) (result i32)
         (call $REFILL)
-    (drop (call $pop))
+        (br_if $endLoop (i32.eqz (call $pop)))
         (local.set $result (call $interpret))
-    (global.set $tos)
+        (local.set $tos)
 
         ;; Check for stack underflow
-    (if (i32.lt_s (global.get $tos) (i32.const 0x10000 (; = STACK_BASE ;)))
-      (drop (call $fail (global.get $tos) (i32.const 0x200B2 (; stack empty ;)))))
+        (if (i32.lt_s (local.get $tos) (i32.const 0x10000 (; = STACK_BASE ;)))
+          (drop (call $fail (local.get $tos) (i32.const 0x200B2 (; stack empty ;)))))
             
         (if (i32.ge_s (local.get $result) (i32.const 0))
           (then
@@ -2780,6 +2782,9 @@
             (call $shell_emit (i32.const 111))
             (call $shell_emit (i32.const 114))))
         (call $shell_emit (i32.const 10))
+        (local.get $tos)
+        (br $loop)))
+      (global.set $tos)
       (local.get $result))
   
   (func (export "push") (param $v i32)

src/web/tests/suite.js

@@ -222,6 +222,15 @@ function loadTests() {
         expect(() => core.interpret()).to.throw();
         expect(output.trim()).to.eql("undefined word: 23FOO");
       });
+
+      it("should interpret a long string", () => {
+        const p = ["1"];
+        for (let i = 0; i < 1000; i++) {
+          p.push(`${1} +`);
+        }
+        forth.interpret(p.join("\n"));
+        expect(stackValues()).to.eql([1001]);
+      });
     });
 
     describe("DUP", () => {

src/web/waforth.ts

@@ -46,7 +46,7 @@ function saveString(s: string, memory: WebAssembly.Memory, addr: number) {
  * */
 class WAForth {
   core?: WebAssembly.Instance;
-  #buffer?: number[];
+  #buffer?: string;
   #fns: Record<string, (f: WAForth) => void>;
 
   /**
@@ -96,7 +96,7 @@ class WAForth {
   async load() {
     let table: WebAssembly.Table;
     let memory: WebAssembly.Memory;
-    this.#buffer = [];
+    this.#buffer = "";
 
     const instance = await WebAssembly.instantiate(wasmModule, {
       shell: {
@@ -111,17 +111,22 @@ class WAForth {
         },
 
         read: (addr: number, length: number): number => {
-          let data = new Uint8Array(
-            (this.core!.exports.memory as WebAssembly.Memory).buffer,
-            addr,
-            length
-          );
-          let n = 0;
-          while (this.#buffer!.length > 0 && n < length) {
-            data[n] = this.#buffer!.shift()!;
-            n += 1;
+          let input: string;
+          if (this.#buffer!.length <= length) {
+            input = this.#buffer!;
+            this.#buffer = "";
+          } else {
+            const i = this.#buffer!.lastIndexOf("\n", length - 1);
+            input = this.#buffer!.substring(0, i + 1);
+            this.#buffer = this.#buffer!.substring(i + 1);
           }
-          return n;
+          // console.log("read: %s (%d remaining)", input, this.#buffer!.length);
+          saveString(
+            input,
+            this.core!.exports.memory as WebAssembly.Memory,
+            addr
+          );
+          return input.length;
         },
 
         key: () => {
@@ -215,16 +220,16 @@ class WAForth {
    * Read data `s` into the input buffer without interpreting it.
    */
   read(s: string) {
-    const data = new TextEncoder().encode(s);
-    for (let i = 0, len = data.length; i < len; ++i) {
-      this.#buffer!.push(data[i]);
-    }
+    this.#buffer = this.#buffer + s;
   }
 
   /**
    * Read data `s` into the input buffer, and interpret.
    */
   interpret(s: string) {
+    if (!s.endsWith("\n")) {
+      s = s + "\n";
+    }
     this.read(s);
     try {
       return (this.core!.exports.interpret as any)();