@Override
protected final Expr unLambda(final Name n) {
final Map<Name, Expr> map = defs.unLambda().getMap();
final LinkedList<Set<Name>> sorted = topoSort(map);
Expr ex = getBody();
for (final Set<Name> names : sorted) {
if (names.size() == 1) {
final Name nm = names.iterator().next();
final Expr def = map.get(nm);
final int uses = ex.numOfUses(nm);
if (uses == 0) {
// name unused, ignore it
log.info("removing unused definition " + nm + ": " + def);
} else if (uses == 1 || def instanceof Value) {
// can be inlined
log.info("inlining " + nm + ": " + def);
ex = ex.inline(nm, def);
} else {
ex = App.create(new Lambda(nm.toString(), ex), map.get(nm));
}
} else {
final Name[] na = names.toArray(new Name[names.size()]);
Expr funs = NIL, res = K.app(ex);
for (final Name element : na) {
funs = CONS.app(map.get(element), funs);
}
funs = K.app(funs);
for (final Name element : na) {
funs = U.app(new Lambda(element.toString(), funs));
if (res.hasFree(element)) {
res = U.app(new Lambda(element.toString(), res));
} else {
// name unused, ignore it
log.info("rewriting unused name: U { " + element + " -> f } ==> (f . tl)");
final Name nm = Name.createName();
res = new Lambda(nm.toString(), App.create(res, TL.app(nm)));
}
}
ex = App.create(res, Y.app(funs));
}
}
return ex.unLambda(n);
}
