1 files changed, 18 insertions, 14 deletions

diff --git a/src/unify.cpp b/src/unify.cpp
index 38f2583..5284bea 100644
--- a/src/unify.cpp
+++ b/src/unify.cpp
@@ -31,7 +31,7 @@ TEnv::buildSubst(AType* genericT, const AType& argsT)
 	Subst subst;
 
 	// Build substitution to apply to generic type
-	const ATuple* genericProtT = genericT->at(1)->as<const ATuple*>();
+	const ATuple* genericProtT = (*(genericT->begin() + 1))->as<const ATuple*>();
 	assert(argsT.size() == genericProtT->size());
 	ATuple::const_iterator g = genericProtT->begin();
 	AType::const_iterator  a = argsT.begin();
@@ -41,9 +41,11 @@ TEnv::buildSubst(AType* genericT, const AType& argsT)
 		if (callArgT->kind == AType::EXPR) {
 			assert(genericArgT->kind == AType::EXPR);
 			assert(callArgT->size() == genericArgT->size());
-			for (size_t i = 0; i < callArgT->size(); ++i) {
-				const AType* gT = genericArgT->at(i)->to<const AType*>();
-				AType*       aT = callArgT->at(i)->to<AType*>();
+			ATuple::const_iterator gi = genericArgT->begin();
+			ATuple::const_iterator ci = callArgT->begin();
+			for (; gi != genericArgT->end(); ++gi, ++ci) {
+				const AType* gT = (*gi)->to<const AType*>();
+				AType*       aT = (*ci)->to<AType*>();
 				if (gT && aT)
 					subst.add(gT, aT);
 			}
@@ -68,11 +70,11 @@ 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);
+	FOREACHP(ATuple::iterator, i, tup)
+		if (**i == *from)
+			*i = to;
+		else if (*i != to)
+			substitute((*i)->to<ATuple*>(), from, to);
 }
 
 /// Compose two substitutions (TAPL 22.1.1)
@@ -124,11 +126,13 @@ unify(const Constraints& constraints)
 		cp.replace(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 = 1; i < s->size(); ++i) {
-			AType* si = s->at(i)->to<AType*>();
-			AType* ti = t->at(i)->to<AType*>();
-			assert(si && ti);
-			cp.push_back(Constraint(si, ti, si->loc));
+		AType::iterator si = s->begin() + 1;
+		AType::iterator ti = t->begin() + 1;
+		for (; si != s->end(); ++si, ++ti) {
+			AType* st = (*si)->to<AType*>();
+			AType* tt = (*ti)->to<AType*>();
+			assert(st && tt);
+			cp.push_back(Constraint(st, tt, st->loc));
 		}
 		return unify(cp);
 	} else {