Level
From Gallium
Levels take parts of Camlp4 Grammar Extensions, expressed with the EXTEND syntax.
Merely an entry is a list of levels.
And a level is an optional name, an optional associativity (left by default) and a list of rules.
Example:
EXTEND Gram expression: [ "top" [ ... ] | "+" [ ... ] | "*" [ ... ] | "**" RIGHTA [ ... ] ... | "simple" [ ... ] ] ; END;;
Here "top", "+", "*", "**", and "simple" are level names.