Implement grammar parser

This implements the grammar struct together with
some other helpful structures like char-set and character.

The grammar struct parses a grammar file and also generates
the FIRST and FOLLOWS tables.

1 files changed, 1 insertions, 0 deletions

diff --git a/.envrc b/.envrc
new file mode 100644
index 0000000..1d953f4
--- /dev/null
+++ b/.envrc
@@ -0,0 +1 @@
+use nix