REPL: Fix for multiline input when using custom eval function

Multiline input doesn't work if user overrides "eval" in
REPL.start. Overriding default eval will stop multiline
inputs on syntax errors because of the current error checking
in the finish callback.

This fixes that issue and allows for a custom recoverableError
check function to be passed the the REPL server for more
customisable use.

fixes nodejs#8640

Author: Michael Edwards

doc/api/repl.markdown

@@ -49,6 +49,8 @@ the following values:
 
  - `eval` - function that will be used to eval each given line. Defaults to
    an async wrapper for `eval()`. See below for an example of a custom `eval`.
+ 
+ - `recoverable` - function that will return a `bool` when passed an error and report if it is recoverable. Use if your `eval` returns none standard errors but you still want the benefits of multiline input.
 
  - `useColors` - a boolean which specifies whether or not the `writer` function
    should output colors. If a different `writer` function is set then this does

lib/repl.js

@@ -82,7 +82,7 @@ function REPLServer(prompt, stream, eval_, useGlobal, ignoreUndefined) {
     return new REPLServer(prompt, stream, eval_, useGlobal, ignoreUndefined);
   }
 
-  var options, input, output, dom;
+  var options, input, output, dom, recoverableCheck;
   if (util.isObject(prompt)) {
     // an options object was given
     options = prompt;
@@ -94,6 +94,7 @@ function REPLServer(prompt, stream, eval_, useGlobal, ignoreUndefined) {
     ignoreUndefined = options.ignoreUndefined;
     prompt = options.prompt;
     dom = options.domain;
+    recoverableCheck = options.recoverable || isRecoverableError;
   } else if (!util.isString(prompt)) {
     throw new Error('An options Object, or a prompt String are required');
   } else {
@@ -298,7 +299,7 @@ function REPLServer(prompt, stream, eval_, useGlobal, ignoreUndefined) {
 
       // If error was SyntaxError and not JSON.parse error
       if (e) {
-        if (e instanceof Recoverable) {
+        if (recoverableCheck(e)) {
           // Start buffering data like that:
           // {
           // ...  x: 1
@@ -952,9 +953,4 @@ function isRecoverableError(e) {
   return e &&
       e.name === 'SyntaxError' &&
       /^(Unexpected end of input|Unexpected token)/.test(e.message);
-}
-
-function Recoverable(err) {
-  this.err = err;
-}
-inherits(Recoverable, SyntaxError);
+}

test/simple/test-repl-options.js

@@ -58,6 +58,7 @@ assert.equal(r1.useColors, r1.rli.terminal);
 // 2
 function writer() {}
 function evaler() {}
+function recoverTester() {}
 var r2 = repl.start({
   input: stream,
   output: stream,
@@ -66,6 +67,7 @@ var r2 = repl.start({
   useGlobal: true,
   ignoreUndefined: true,
   eval: evaler,
+  recover: recoverTester,
   writer: writer
 });
 assert.equal(r2.input, stream);