From 84274ac380968df9fb49bcbf6f3d494536d7a548 Mon Sep 17 00:00:00 2001
From: David Robillard <d@drobilla.net>
Date: Sun, 28 Jun 2009 23:21:30 +0000
Subject: Split unification into a separate file than type constraints.

git-svn-id: http://svn.drobilla.net/resp/tuplr@159 ad02d1e2-f140-0410-9f75-f8b11f17cedd
---
 typing.cpp | 75 --------------------------------------------------------------
 1 file changed, 75 deletions(-)

(limited to 'typing.cpp')

diff --git a/typing.cpp b/typing.cpp
index 0e63f26..5791fdc 100644
--- a/typing.cpp
+++ b/typing.cpp
@@ -230,78 +230,3 @@ APrimitive::constrain(TEnv& tenv, Constraints& c) const
 	}
 }
 
-
-/***************************************************************************
- * Type Inference/Substitution                                             *
- ***************************************************************************/
-
-static void
-substitute(ATuple* tup, const AST* from, AST* to)
-{
-	if (!tup) return;
-	for (size_t i = 0; i < tup->size(); ++i)
-		if (*tup->at(i) == *from)
-			tup->at(i) = to;
-		else if (tup->at(i) != to)
-			substitute(tup->at(i)->to<ATuple*>(), from, to);
-}
-
-Subst
-Subst::compose(const Subst& delta, const Subst& gamma) // TAPL 22.1.1
-{
-	Subst r;
-	for (Subst::const_iterator g = gamma.begin(); g != gamma.end(); ++g) {
-		Subst::const_iterator d = delta.find(g->second);
-		r.add(g->first, ((d != delta.end()) ? d : g)->second);
-	}
-	for (Subst::const_iterator d = delta.begin(); d != delta.end(); ++d) {
-		if (gamma.find(d->first) == gamma.end())
-			r.add(d->first, d->second);
-	}
-	return r;
-}
-
-void
-substConstraints(Constraints& constraints, AType* s, AType* t)
-{
-	for (Constraints::iterator c = constraints.begin(); c != constraints.end();) {
-		Constraints::iterator next = c; ++next;
-		if (*c->first  == *s) c->first  = t;
-		if (*c->second == *s) c->second = t;
-		substitute(c->first, s, t);
-		substitute(c->second, s, t);
-		c = next;
-	}
-}
-
-Subst
-TEnv::unify(const Constraints& constraints) // TAPL 22.4
-{
-	if (constraints.empty()) return Subst();
-	AType*      s  = constraints.begin()->first;
-	AType*      t  = constraints.begin()->second;
-	Constraints cp = constraints;
-	cp.erase(cp.begin());
-
-	if (*s == *t) {
-		return unify(cp);
-	} else if (s->var() && !t->contains(s)) {
-		substConstraints(cp, s, t);
-		return Subst::compose(unify(cp), Subst(s, t));
-	} else if (t->var() && !s->contains(t)) {
-		substConstraints(cp, t, s);
-		return Subst::compose(unify(cp), Subst(t, s));
-	} else if (s->kind == AType::EXPR && s->kind == t->kind && s->size() == t->size()) {
-		for (size_t i = 0; i < s->size(); ++i) {
-			AType* si = s->at(i)->to<AType*>();
-			AType* ti = t->at(i)->to<AType*>();
-			if (si && ti)
-				cp.push_back(Constraint(si, ti, si->loc));
-		}
-		return unify(cp);
-	} else {
-		throw Error(s->loc ? s->loc : t->loc,
-				(format("type is `%1%' but should be `%2%'") % s->str() % t->str()).str());
-	}
-}
-
-- 
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