Clean up production::to_string
Simplify sample grammars a little.
Clean up grammar::to_string
Merge branch 'master' into simple_productions
Make symbols orderable.
Merge branch 'master' into simple_productions
Rework production_list PP to merge duplicate left-hand sides
Clean up test grammar.
Clean up test_number grammars
More cleanup
Add apply() for production_list
More test cleanup
Improve YAML assertions
More test cleanup
Assume one RHS per production.
Return a sequence from production::rhs
Add test for empty RHS
Store a sequence in production
Update first production ctor
Update second ctor