# Well-parenthesized language parser
This project is a JavaCC parser configuration which generates a parser for a language with well-balanced parentheses.
The features that this language has is:
- Each string accepted by the language consists of multiple lines (but at least 1 line).
- Lines must not be empty.
- Lines must contain well-balanced parentheses, e.g. `()`, `()()()`, `(()())`, `(((())))`.
- Only parentheses are allowed, so any other character makes the input invalid.
- (As an exception to the first rule) there must be a blank final line at the end of the input.

E.g. the following is a good input to the parser:
```
()(())
(())(((()())))
((((((((((()))))))))))
(())()()()()()
((()()())()()(()(())))()
<blank line here>
```

## How to run
To build the Java code and run:
`./run.sh`. This is an alias for:
```bash
javacc assignment.jj && javac *.java && java Assignment < test.txt > output.txt 2> err.txt
```

### Output
The standard output stream will contain the parser's decision as to whether the string is valid — the output will either be `PASS` or `FAIL`.
If it is `FAIL`, the standard error will also contain the line number of the first error that caused the invalidity.