gf-core/transfer/examples/reflexive/reflexive.tra

{-

$ ../../transferc -i../../lib reflexive.tra

$ gf English.gf reflexive.trc

> p -tr "John sees John" | at -tr reflexivize_S | l
PredV2 See John John
ReflV2 See John
John sees himself

> p -tr "John and Bill see John and Bill" | at -tr reflexivize_S | l
PredV2 See (ConjNP And John Bill) (ConjNP And John Bill)
ReflV2 See (ConjNP And John Bill)
John and Bill see themselves

> p -tr "John sees Mary" | at -tr reflexivize_S | l
PredV2 See John Mary
PredV2 See John Mary
John sees Mary

-}

import tree

reflexivize : (C : Cat) -> Tree C -> Tree C
reflexivize _ (PredV2 v s o) | eq ? (eq_Tree ?) s o = ReflV2 v s
reflexivize _ t = composOp ? ? compos_Tree ? reflexivize t

reflexivize_S : Tree S -> Tree S
reflexivize_S = reflexivize S

{-
With a type checker and hidden arguments we could write:

reflexivize : {C : Cat} -> Tree C -> Tree C
reflexivize (PredV2 v s o) | s == o = ReflV2 v s
reflexivize t = composOp reflexivize t

-}