Protect syntaxes es inside syntaxes in let_impl
Add is_same
Adding apply
Make bad_match lazy
Remove unnecessary usage of lazy
Stop building docs in ci
Merge remote-tracking branch 'upstream/master'
Make nullary lambdas template metaprogramming values
Testing let and currying
Merge remote-tracking branch 'upstream/master'
Implemented unary_item and seq grammar elements.
Increased the MPLLIBS_SEQUENCE_MAX_ARGUMENT macro to 7 in sequence.hpp for the unary_item implementation.
Added new test cases in regress.txt for the new elements.
The tester.cpp is for debugging purpose.