Remove need for prompt sync

package.json

@@ -24,17 +24,12 @@
   "devDependencies": {
     "@ava/typescript": "^1.1.1",
     "@types/node": "^15.6.2",
-    "@types/prompt-sync": "^4.1.0",
-    "@types/prompt-sync-history": "^1.0.1",
     "ava": "^3.15.0",
     "prettier": "^2.3.0",
     "ts-node": "^10.0.0",
     "typescript": "^4.3.2"
   },
-  "dependencies": {
-    "prompt-sync": "^4.2.0",
-    "prompt-sync-history": "^1.0.1"
-  },
+  "dependencies": {},
   "ava": {
     "extensions": {
       "ts": "module"

src/index.ts

@@ -1,6 +1,5 @@
 #!/usr/bin/env node
-import PromptSync from "prompt-sync";
-import History from "prompt-sync-history";
+import { createInterface, ReadLine } from "readline";
 
 import { handleError, redText } from "./libzug/builtins/imports";
 // @ts-ignore
@@ -12,42 +11,53 @@ import { LErr, lvalRead } from "./libzug/lval";
 main();
 
 function main() {
-  const history = History(".zug-history", 1000);
-  const promptSync = PromptSync({
-    sigint: false,
-    // @ts-ignore  (seems to be misisng from typing)
-    eot: true,
-    history: history,
+  // Set up line reader
+  const readline = createInterface({
+    input: process.stdin,
+    output: process.stdout,
+    terminal: true,
   });
+  readline.setPrompt("zug> ");
+
   const interpreter = new Interpreter();
+
   let res = loadFile(interpreter.env, "prelude", true);
   if (res instanceof LErr) {
     throw new Error("Failed to load prelude: " + res.s);
   }
 
   console.log("zug version 0.2.0");
   console.log("press ctrl+d to exit");
-
-  while (true) {
-    const line = promptSync("zug> ");
-    if (!line) {
-      continue;
-    }
-
-    try {
-      var tree = parser.parse(line);
-    } catch (err) {
-      handleError(err, line);
-      continue;
+  readline.prompt();
+
+  readline.on("line", (line) => {
+    if (line) {
+      try {
+        var tree = parser.parse(line);
+      } catch (err) {
+        handleError(err, line);
+        readline.prompt();
+        return;
+      }
+
+      let result = interpreter.interpret(lvalRead(tree));
+      if (result.type === "ERROR") {
+        console.log(redText(result.print()));
+      } else {
+        console.log(result.print());
+      }
     }
+    readline.prompt();
+  });
 
-    let result = interpreter.interpret(lvalRead(tree));
-    if (result.type === "ERROR") {
-      console.log(redText(result.print()));
-    } else {
-      console.log(result.print());
-    }
-  }
+  readline.on("SIGINT", () => {
+    // @ts-ignore
+    readline.clearLine();
+    readline.prompt();
+  });
 
-  history.save();
+  readline.on("close", () => {
+    console.log("goodbye!");
+    process.exit(0);
+  });
 }

src/libzug/builtins/index.ts

@@ -4,7 +4,7 @@ import { def, doc, lambda, let_, set } from "./defn";
 import { import_ } from "./imports";
 import { Builtin, LCallable, LObject } from "../lval";
 import { getattr, keys, object, values } from "./object";
-import { env as getenv, exit, input, print } from "./sys";
+import { env as getenv, exit, print } from "./sys";
 import { list, head, tail, join, evaluate } from "./array";
 
 export default function seedEnv(env?: LObject): LObject {
@@ -165,12 +165,12 @@ export default function seedEnv(env?: LObject): LObject {
     print,
     "print [..strings]\n" + "Print the strings to stdout."
   );
-  newBuiltin(
-    env,
-    "input",
-    input,
-    "input [string?]\n" + "Receive input from stdin, possibly with a prompt string."
-  );
+  // newBuiltin(
+  //   env,
+  //   "input",
+  //   input,
+  //   "input [string?]\n" + "Receive input from stdin, possibly with a prompt string."
+  // );
   newBuiltin(
     env,
     "import",

src/libzug/builtins/sys.ts

@@ -1,28 +1,27 @@
-import PromptSync from "prompt-sync";
 import { LVal, LObject, LErr, LNum, NIL, LNil, LString } from "../lval";
 
 export function print(env: LObject, args: Array<LVal>): LNil {
   console.log(args.map((a) => a.print()).join(" "));
   return NIL;
 }
 
-export function input(env: LObject, args: Array<LVal>): LVal {
-
-  let prompt: string;
-  if (args.length === 0) {
-    prompt = "";
-  } else if (args.length === 1) {
-    const arg = args[0];
-    if (!(arg instanceof LString)) {
-      return new LErr(`TypeError: input takes STRING, not ${arg.type}`);
-    }
-    prompt = arg.s;
-  } else {
-    return new LErr(`TypeError: input takes at most one argument. Received ${args.length}`)
-  }
-
-  return new LString(PromptSync()(prompt))
-}
+// export function input(env: LObject, args: Array<LVal>): LVal {
+//
+//   let prompt: string;
+//   if (args.length === 0) {
+//     prompt = "";
+//   } else if (args.length === 1) {
+//     const arg = args[0];
+//     if (!(arg instanceof LString)) {
+//       return new LErr(`TypeError: input takes STRING, not ${arg.type}`);
+//     }
+//     prompt = arg.s;
+//   } else {
+//     return new LErr(`TypeError: input takes at most one argument. Received ${args.length}`)
+//   }
+//
+//   return new LString(PromptSync()(prompt))
+// }
 
 
 export function env(env: LObject, args: Array<LVal>) {