Python3 runtime raises AttributeError in Parser.py #3052
Description
I met an AttributeError when trying codes in the 'Actions and Attributes' section.
I used the following grammar which is translated into a Python3 version from the sample grammar shown in that section.
grammar DynScope;
prog: block ;
block
/* List of symbols defined within this block */
locals [
symbols = list()
]
: '{' decl* stat+ '}'
// print out all symbols found in block
// $block::symbols evaluates to a List as defined in scope
{print("symbols=%s" % ($symbols))}
;
/** Match a declaration and add identifier name to list of symbols */
decl: 'int' ID {$block::symbols.append($ID.text);} ';' ;
/** Match an assignment then test list of symbols to verify
* that it contains the variable on the left side of the assignment.
* Method contains() is List.contains() because $block::symbols
* is a List.
*/
stat: ID '=' INT ';'
{
if not $ID.text in $block::symbols:
print("Undefined variable: %s" % ($ID.text))
}
| block
;
ID : [a-z]+ ;
INT : [0-9]+ ;
WS : [ \t\r\n]+ -> skip ;
Executing the Python3 target generated from the above grammar leads to an AttributeError, saying that the Context object has no ruleIndex attribute.
Below is the last part of the traceback.
...
File "/usr/local/lib/python3.9/site-packages/antlr4/Parser.py", line 456, in getInvokingContext
if ctx.ruleIndex == ruleIndex:
AttributeError: 'DeclContext' object has no attribute 'ruleIndex'
There was a previous issue #2745 talking about this, however, it seems that this problem is still remaining unsolved.
Manually changing the line into below solves this problem.
if ctx.getRuleIndex() == ruleIndex: