Antlr Calc Build $ cd src/app $ antlr4 LibExpr.g4 -no-listener -visitor $ mkdir bin $ javac *.java -d bin Usage $ cd bin $ echo "a = 3\nb = 4\nc = a + 5\n2 * (1 + 3)\n(a - b) * 2\n" > calc.expr $ java app.App calc.expr