Antlr v4 : can't set any kind of error monitoring on parser. How to throw exceptions

[Emiel Steerneman]

All I want from Antlr is to throw an exception when it encouters something like "mismatched input" or "extraneous input" etc.

I tried

    parser.setErrorHandler(BailErrorStrategy)                  ERROR: 'parser' object has no attribute 'setErrorHandler'

    parser.addErrorListener(BaseErrorListener)               ERROR: 'BaseErrorListener' is not defined

CODE

from grammar_paidLexer import grammar_paidLexer

from grammar_paidParser import grammar_paidParser

from grammar_paidListener import grammar_paidListener

input  = FileStream(file)

lexer = grammar_paidLexer(input)

stream = CommonTokenStream(lexer)

parser = grammar_paidParser(stream)

parser.setErrorHandler(BailErrorStrategy)

parser.addErrorListener(BaseErrorListener)

try:

tree = parser.receipt()

except Exception as e:

print e

sys.exit()

listener = grammar_paidListener()

walker = ParseTreeWalker()

walker.walk(listener, tree)

[Emiel Steerneman]

I fixed it myself:

from antlr4.error.ErrorStrategy import ErrorStrategy

class MyErrorListener( ErrorListener ):

def __init__(self):

super(MyErrorListener, self).__init__()

def syntaxError(self, recognizer, offendingSymbol, line, column, msg, e):

raise Exception("syntaxError!")

def reportAmbiguity(self, recognizer, dfa, startIndex, stopIndex, exact, ambigAlts, configs):

raise Exception("reportAmbiguity!")

def reportAttemptingFullContext(self, recognizer, dfa, startIndex, stopIndex, conflictingAlts, configs):

raise Exception("reportAttemptingFullContext!")

def reportContextSensitivity(self, recognizer, dfa, startIndex, stopIndex, prediction, configs):

raise Exception("reportContextSensitivity!")

parser._listeners = [ MyErrorListener() ]

try:

tree = parser.receipt()

except Exception as e:

print e

return

Op woensdag 26 augustus 2015 15:55:48 UTC+2 schreef Emiel Steerneman:

[Eric Vergnaud]

Hi,

_listeners is private, you should write:

parser.addErrorListener(MyErrorListener()]

Eric