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https://issues.apache.org/jira/browse/JEXL-367?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17539002#comment-17539002
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Dmitri Blinov commented on JEXL-367:
------------------------------------
There are a couple of notes on current named function implementation, if you
don't mind...
It seems Jexl treats named functions like expressions, not statments. This
allows a little weird syntax like
{code:java}
@Test
public void testNamedFuncIsExpr() {
String src = "var i = function foo(x) { x + x }; i(6)";
JexlEngine jexl = createEngine();
JexlScript script = jexl.createScript(src);
Object result = script.execute(null);
Assert.assertEquals(12, result);
}
{code}
Also, since declaring a named function means to implicitly declare a variable,
then logically, local variable declaration feature should be checked, to see if
we are allowed to do so in our context, for example if we are evaluating a
simple expression.
Moreover, since we are declaring a lexical variable with named function, then I
think, in analogy with `var` we should restrict conditional single-statement
declarations to avoid strange errors like in example
{code:java}
@Test
public void testNamedFuncConditional() {
String src = "if (false) function foo(x) { x + x }; var foo = 1";
JexlEngine jexl = createEngine();
JexlScript script = jexl.createScript(src);
Object result = script.execute(null);
Assert.assertEquals(1, result);
}
{code}
> Named function and fat-arrow (=>) lambda syntax
> -----------------------------------------------
>
> Key: JEXL-367
> URL: https://issues.apache.org/jira/browse/JEXL-367
> Project: Commons JEXL
> Issue Type: Wish
> Affects Versions: 3.2.1
> Reporter: Hussachai Puripunpinyo
> Assignee: Henri Biestro
> Priority: Major
>
> The JEXL code surprisingly looks a lot like Javascript. I think this change
> is a good transition for folks to update the code, and it's pretty fine if
> they can tolerate using the deprecate syntax and don't mind seeing a warning
> log pop up every time.
> I'd like to propose supporting => and deprecate ->.
> The reasons are
> - JavaScript becomes very popular and many people are familiar with it.
> - JEXL is more like for a quick short script. In many scenarios, the target
> audiences are not a programer. They often mistake a language as a JavaScript
> (from my experience).
> - JEXL syntax already looks a lot like JavaScript
> -- var for variable declaration (Java added in Java 10, but JavaScript
> supports this from the beginning)
> -- The function keyword
> -- Implicit type coercion
> -- Ternary operator
> The proposed change.
> * Support => in addition to ->
> * Deprecate -> and show a warning log when it's used.
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