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https://issues.apache.org/jira/browse/JEXL-303?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16846530#comment-16846530
]
Dmitri Blinov commented on JEXL-303:
------------------------------------
Sorry, but it has turned out the solution I proposed does not take into account
nested blocks in {{StatementLookahead()}}. Now I think I understand the real
reason for the initial issue. The problem is with {{ExpressionStatement()}}
grammar which may have trailing semicolon. In the failing case {{if (0) 1 else
2;}} that last semicolon was treated as part of {{ExpressionStatement()}} of
{{else}} part, not the statement separator, thats why the {{LOOKAHEAD(<LCURLY>
Statement() <SEMICOL>) Block()}} didn't work.
Anyway, I think I have more robust grammar proposal for this. First, we need to
change {{SetLiteral}} lookahead from
{code:java}
void PrimaryExpression() #void : {}
{
...
LOOKAHEAD( <LCURLY> Expression()) SetLiteral()
...
}
{code}
to
{code:java}
void PrimaryExpression() #void : {}
{
...
LOOKAHEAD( <LCURLY> Expression() (<COMMA> | <RCURLY>)) SetLiteral()
...
}
{code}
Second, we can change the Statement() grammar to this
{code:java}
void Statement() #void : {}
{
<SEMICOL>
| LOOKAHEAD(<ANNOTATION>) AnnotatedStatement()
| LOOKAHEAD(Expression()) ExpressionStatement()
| Block()
| IfStatement()
| ForeachStatement()
| WhileStatement()
| DoWhileStatement()
| ReturnStatement()
| Continue()
| Break()
| Var()
| Pragma()
}
{code}
So that we don't need {{StatementLookahead()}} anymore...
> Block syntax is broken
> ----------------------
>
> Key: JEXL-303
> URL: https://issues.apache.org/jira/browse/JEXL-303
> Project: Commons JEXL
> Issue Type: Bug
> Affects Versions: 3.1
> Reporter: Dmitri Blinov
> Assignee: Henri Biestro
> Priority: Major
> Fix For: 3.2
>
>
> The following script fails to parse correctly
> {code}
> {if (0) 1 else 2; var x = 1;}
> {code}
> while the following script parses perfectly
> {code}
> {var x = 1; if (0) 1 else 2;}
> {code}
> Tested with
> {code}
> @Test
> public void testOuterBlock() throws Exception {
> JexlScript e = JEXL.createScript("{if (0) 1 else 2; var x = 1;}");
> JexlContext jc = new MapContext();
> Object o = e.execute(jc);
> Assert.assertEquals("Block result is wrong", 1, o);
> }
> {code}
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