REGEX ENGINE

I've thought for a while it would be fun and interesting to write my
own regular expression engine using Thompson's construction algorithm,
so here we are.


                               Grammar

The engine does not support any specific standard's syntax, unless by
coincidence.  The grammar I've implemented for expressions is:

	regex ::= sequence ( '|' sequence )*
	sequence ::= term+
	term ::= ( '.' | class | literal | '(' regex ')' ) quantifier?
	class ::= '[' '^'? literal+ ']'
	literal ::= non-special | '\' special
	quantifier ::= '*' | '+' | '?'
	special ::= quantifier | '|' | '(' | ')' | '[' | ']' | '^' | '\'


                      Building and Running Tests

The build uses CMake.  There are two scripts, build.sh and test.sh,
which will (much to everybody's shock) build the project and run the
tests.  I use Clang but the code is ISO C11 so it should compile just
fine with GCC.  You might need to faff with CMakeLists.txt to get it
to work with another compiler due to command-line flag nonsense.

	scripts/build.sh  # Compile library, demo and tests
	scripts/test.sh   # Run tests

There is also an entr.sh script which will watch all the project's
files and rebuild then rerun the tests on any changes (uses entr --
hence the name of the script).