Safe Haskell | Safe |
---|---|
Language | Haskell2010 |
TAG conversion into flat production rules.
Factorized grammar
A production rule, responsible for recognizing a specific
(unique) non-trivial (of height > 0
) subtree of an elementary
grammar tree. Due to potential subtree sharing, a single rule can
be responsible for recognizing a subtree common to many different
elementary trees.
Invariants:
A label is a data type over which flat production rules are constructed. In particular, it describes what information is stored in the heads of rules, as well as in the elements of the their bodies.
NonT | A non-terminal symbol originating from a branching,
non-spine node, optionally marked with a |
Term t | A terminal symbol |
AuxRoot | A non-terminal originating from a root of an auxiliary tree |
| |
AuxFoot | A non-terminal originating from a foot of an auxiliary tree |
| |
AuxVert | A non-terminal originating from a spine of an auxiliary tree (unless root or foot) |