ARROW_FUNCTION position set error

[nabice]

JS Code:
setTimeout(() => {}, 0);

In org.mozilla.javascript.Parser.java, line 887,
params.position is -1, this will make a wrong FunctionNode position.

[clearw5]

Rhino supports arrow function? I try your code but only get a syntax error.

[nabice]

支持的。可能你没有用到最新的版本？

[clearw5]

I am using the latest release 1.7.7.1 but cannot run any code with arrow function. How to enable this feature?
怎么支持呀 我设置语言版本为1.8和ES6也不行耶

[nabice]

不太清楚你怎么弄的，直接编译最新的是可以的。没有进行什么设置。

[clearw5]

I finally found it was supported in the latest SNAPSHOT.

[Yidadaa]

@hyb1996 活捉autoJS作者2333

[gbrail]

Since this seems to be fixed in master I'm closing this.

[nabice]

@gbrail, I found it still not fixed. FunctionNode has wrong position.

[gbrail]

OK. I must be misunderstanding the problem then. Perhaps if you can give us some code to reproduce it and describe what's incorrect then we can take a look.

…

On Tue, Nov 14, 2017 at 9:07 PM, nabice ***@***.***> wrote: @gbrail <https://github.com/gbrail>, I found it still not fixed. FunctionNode has wrong position. — You are receiving this because you were mentioned. Reply to this email directly, view it on GitHub <#303 (comment)>, or mute the thread <https://github.com/notifications/unsubscribe-auth/AAf0aypJeI-Sp4c7QDjwEat048qy7_9Dks5s2nGcgaJpZM4NF5a5> .

[nabice]

file: a.js
setTimeout(() => {}, 0);

When a.js is parsed, setTimeout's first argument is a FucntionNode instance. Property position of the instance should be 12, but 0 we get.
It can be fixed like this, probably not correct:

diff --git a/src/org/mozilla/javascript/Parser.java b/src/org/mozilla/javascript/Parser.java
index da03f0c7..787e8bc3 100644
--- a/src/org/mozilla/javascript/Parser.java
+++ b/src/org/mozilla/javascript/Parser.java
@@ -3106,7 +3106,7 @@ public class Parser
             Comment jsdocNode = getAndResetJsDoc();
             int lineno = ts.lineno;
             int begin = ts.tokenBeg;
-            AstNode e = (peekToken() == Token.RP ? new EmptyExpression() : expr());
+            AstNode e = (peekToken() == Token.RP ? new EmptyExpression(ts.tokenBeg) : expr());
             if (peekToken() == Token.FOR) {
                 return generatorExpression(e, begin);
             }

[sainaen]

@nabice
For what it's worth, I don't see how to fix this differently. I even went ahead and create a pull request. 🙂

Well, there's one minor thing: I noticed that this way position will point at the opening parenthesis, while in case of parameters present (e.g. (a, b) => a+b) it will be one character further (ParenthesisedExpression copies its child position) — is it ok? (See the test in my PR for example of this.)

[gbrail]

Can you please take a look at @sainaen 's PR and see if it fixes this for you?

#363

Thanks!

[nabice]

Yes, it does.