Tag: lexer

ANTLR4: How to match extra spaces at the beginning of a line?

I tried to match the extra space at the beginning of the line, but it didn’t work. How to modify the lexer rule to match? TestParser.g4: TestLexer.g4: Text: Java code: The output is as follows: The idea is that when a non-option line is encountered in OPTION_MODE, the mode will pop up, and now when there is an extra space

Do I scan twice if I call scanner.hasNext and then scanner.next

java lexer parsing tokenize

Do I scan twice if I call scanner.hasNext(pattern) and then scanner.next(pattern) with the same pattern on java.util.Scanner Let’s say i have this code with a lots of cases (trying to make a lexer): …

Java and regex lexer

java lexer regex

I am trying to make some sort of Lexer in Java using regex for a custom markdown “language” I’m making, it’s my first time working with this stuff so a little lost on a few things. An …

Coding a propositional logic parser by hand

finite-automata grammar java lexer parsing

I need to do a parser for propositional logic. I pretend to do it by hand implemented like a recursive descent parser in java. My question is about the lexer, is it really needed for this job? I mean …