MyTreeVisitor.py

from TreeVisitor import TreeVisitor


class MyTreeVisitor(TreeVisitor):

    def visitLeaf(self, ctx):
        return True  # une feuille est un A.B.

    def visitNode(self, ctx):
        children = ctx.int_tree()
        if not (len(children) == 2):
            return False
        else:
            for tree in children:
                if not self.visit(tree):
                    return False
            return True

    def visitTop(self, ctx):
        thetree = ctx.int_tree()
        return self.visit(thetree)

Tree.g4

grammar Tree;


int_tree_top : int_tree EOF #top
    ;

int_tree:  INT    #leaf
    | '(' INT int_tree+ ')'  #node
    ;


INT: [0-9]+;
WS  :   (' '|'\t'|'\n')+  -> skip;

tree_main.py

from TreeLexer import TreeLexer
from TreeParser import TreeParser

from MyTreeVisitor import MyTreeVisitor

from antlr4 import InputStream, CommonTokenStream
import sys


def main():
    lexer = TreeLexer(InputStream(sys.stdin.read()))
    stream = CommonTokenStream(lexer)
    parser = TreeParser(stream)
    tree = parser.int_tree_top()
    print(tree)
    visitor = MyTreeVisitor()
    b = visitor.visit(tree)
    print("Is it a binary tree ? "+str(b))


if __name__ == '__main__':
    main()