M Makefile → Makefile

@@ -7,7 +7,8 @@ hex: hex.c
 	$(CC) $(CFLAGS) $(LDFLAGS) $< -o $@
 
 wasm: hex.c
-	 emcc hex.c -o web/assets/hex.js --pre-js web/assets/hex-playground.js
+	 emcc -sASYNCIFY -sEXPORTED_RUNTIME_METHODS=stringToUTF8 hex.c -o web/assets/hex.js --pre-js web/assets/hex-playground.js
+
 
 .PHONY: clean
 clean:

M hex.c → hex.c

@@ -1,5 +1,30 @@ 
 #include "hex.h"
 
+#ifdef EMSCRIPTEN
+#include <emscripten.h>
+
+EM_ASYNC_JS(char *, em_fgets, (const char* buf, size_t bufsize), {
+  return await new Promise((resolve, reject) => {
+      if (Module.pending_lines.length > 0) {
+        resolve(Module.pending_lines.shift());
+      } else {
+        Module.pending_fgets.push(resolve);
+      }
+  }).then((s) => {
+      // convert JS string to WASM string
+      let l = s.length + 1;
+      if (l >= bufsize) {
+        // truncate
+        l = bufsize - 1;
+      }
+      Module.stringToUTF8(s.slice(0, l), buf, l);
+      return buf;
+  });
+});
+
+#endif
+
+
 // Common operations
 #define POP(ctx, x) hex_item_t x = hex_pop(ctx)
 #define FREE(ctx, x) hex_free_item(ctx, x)
@@ -3814,26 +3839,25 @@ fclose(file);
     return content;
 }
 
-// REPL implementation
-void hex_repl(hex_context_t *ctx)
+static void do_repl(void *v_ctx) 
 {
-
-    char line[1024];
-
-    printf("   _*_ _\n");
-    printf("  / \\hex\\*\n");
-    printf(" *\\_/_/_/ v%s - Press Ctrl+C to exit.\n", HEX_VERSION);
-    printf("      *\n");
-
-    while (1)
-    {
+       hex_context_t *ctx = (hex_context_t *)v_ctx;
+        char line[1024];
+#ifdef EMSCRIPTEN
+        char *p = line;
+        p = em_fgets(line, 1024);
+        if (!p)
+        {
+            printf("Error reading output");
+        }
+#else
         printf("> "); // Prompt
         if (fgets(line, sizeof(line), stdin) == NULL)
         {
             printf("\n"); // Handle EOF (Ctrl+D)
-            break;
+            return;
         }
-
+#endif
         // Normalize line endings (remove trailing \r\n or \n)
         line[strcspn(line, "\r\n")] = '\0';
 
@@ -3846,7 +3870,32 @@ hex_print_item(stdout, ctx->stack.entries[ctx->stack.top]);
             // hex_print_item(stdout, HEX_STACK[HEX_TOP]);
             printf("\n");
         }
+        return;
+
+
+}
+
+// REPL implementation
+void hex_repl(hex_context_t *ctx)
+{
+
+
+    printf("   _*_ _\n");
+    printf("  / \\hex\\*\n");
+    printf(" *\\_/_/_/ v%s - Press Ctrl+C to exit.\n", HEX_VERSION);
+    printf("      *\n");
+
+#ifdef __EMSCRIPTEN__
+  int fps = 0;
+  int simulate_infinite_loop = 1;
+  emscripten_set_main_loop_arg(do_repl, ctx, fps, simulate_infinite_loop);
+#else
+
+    while (1)
+    {
+      do_repl(ctx);
     }
+#endif
 }
 
 void hex_handle_sigint(int sig)

M web/assets/hex-playground.js → web/assets/hex-playground.js

@@ -1,44 +1,27 @@ 
-Module.preRun = () => {
 
-    let stdinBuffer = [];
-    const inputBox = document.querySelector("article input")
-    const input = inputBox.value;
-    inputBox.addEventListener("keydown", (event) => {
-        if (event.key === "Enter" && !event.shiftKey) {
-            event.preventDefault();
-            inputBox.value = ""; // Clear the textarea
-            stdinBuffer.push(...input + "\n"); // Add input to the buffer
-          }
-    });
-    function stdin() {
-        if (i < input.length) {
-            var code = input.charCodeAt(i);
-            ++i;
-            return code;
-          } else {
-            return null;
-          }
-    };
 
-    let stdoutBuffer = "";
-    function stdout(code) {
-      if (code === "\n".charCodeAt(0) && stdoutBuffer !== "") {
-        document.querySelector("article section").textContent += stdoutBuffer + "\n";
-        stdoutBuffer = "";
-      } else {
-        stdoutBuffer += String.fromCharCode(code);
-      }
-    }
+
+Module.pending_fgets = [];
+Module.pending_chars = [];
+Module.pending_lines = [];
+Module.print = (text) => {
+  document.querySelector("article section").textContent += text + '\n';
+};
+
+const inputBox = document.querySelector("article input");
 
-    let stderrBuffer = "";
-    function stderr(code) {
-      if (code === "\n".charCodeAt(0) && stderrBuffer !== "") {
-        document.querySelector("article section").textContent += stderrBuffer + "\n";
-        stderrBuffer = "";
-      } else {
-        stderrBuffer += String.fromCharCode(code);
-      }
-    }
-    FS.init(stdin, stdout, stderr);
-}
+inputBox.addEventListener("keydown", (e) => {
+  if (e.key === 'Enter') {
+    e.preventDefault();
+    Module.pending_lines.push(Module.pending_chars.join(''));
+    Module.pending_chars = [];
+    inputBox.value = '';
+  } else {
+    Module.pending_chars.push(e.key);
+  }
+  if (Module.pending_fgets.length > 0 && Module.pending_lines.length > 0) {
+    let resolver = Module.pending_fgets.shift();
+    resolver(Module.pending_lines.shift());
+  }
+});