Ugh.

The evaluator is basically a yacc grammar with commands to evaluate a mathematical expression built-in to the
	grammar reductions. This is done using the special $ variables in YACC. Note that a special lexer had to 
	be written. This lexer can be found in lexer.c. eval() is actually found at the bottom of
	expression.y. For time and space efficiency only the mathematical operators that may be generated
	while calculating a summation have been included in the mathematical expression grammar found 
	within the expression.y file.

To remake the lexer, type 'make lexer.o' -- this should be done before typing 'make eval.o' when 
	integrating changes to the lexer.
To remake the eval() function, type 'make eval.o'.
