### Put transformations "subst" and "subst_all" in a separate file

Incidentally, move the local "fold" function of apply.ml into the general module Trans

Showing

**src/transform/subst.ml**0 → 100644

Incidentally, move the local "fold" function of apply.ml into the general module Trans

Showing
with
**333 additions**
and
**310 deletions**
**+333**
**-310**