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README.md

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+# 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.