Type and const correct Subst::apply.

git-svn-id: http://svn.drobilla.net/resp/tuplr@232 ad02d1e2-f140-0410-9f75-f8b11f17cedd

3 files changed, 20 insertions, 19 deletions

diff --git a/src/compile.cpp b/src/compile.cpp
index 3918617..d525f57 100644
--- a/src/compile.cpp
+++ b/src/compile.cpp
@@ -55,7 +55,7 @@ ACall::compile(CEnv& cenv)
 		protT.push_back(cenv.type(*i));
 
 	AType fnT(loc);
-	fnT.push_back(cenv.penv.sym("Fn"));
+	fnT.push_back(cenv.tenv.Fn);
 	fnT.push_back(&protT);
 	fnT.push_back(cenv.type(this));
 
diff --git a/src/constrain.cpp b/src/constrain.cpp
index 982f195..0c9951c 100644
--- a/src/constrain.cpp
+++ b/src/constrain.cpp
@@ -101,7 +101,7 @@ AFn::constrain(TEnv& tenv, Constraints& c) const
 		(exp = *i)->constrain(tenv, c);
 
 	AType* bodyT = tenv.var(exp);
-	AType* fnT = tup<AType>(loc, tenv.penv.sym("Fn"), protT, bodyT, 0);
+	AType* fnT = tup<AType>(loc, tenv.Fn, protT, bodyT, 0);
 	Object::pool.addRoot(fnT);
 
 	tenv.pop();
@@ -119,8 +119,7 @@ ACall::constrain(TEnv& tenv, Constraints& c) const
 	if (fnType->kind != AType::VAR) {
 		if (fnType->kind == AType::PRIM
 				|| fnType->size() < 2
-				|| !fnType->head()->to<const ASymbol*>()
-				|| fnType->head()->to<const ASymbol*>()->cppstr != "Fn")
+				|| fnType->head()->str() != "Fn")
 			throw Error(loc, (format("call to non-function `%1%'") % head()->str()).str());
 
 		size_t numArgs = fnType->prot()->size();
@@ -133,7 +132,7 @@ ACall::constrain(TEnv& tenv, Constraints& c) const
 	for (const_iterator i = begin() + 1; i != end(); ++i)
 		argsT->push_back(tenv.var(*i));
 
-	c.constrain(tenv, head(), tup<AType>(head()->loc, tenv.penv.sym("Fn"), argsT, retT, 0));
+	c.constrain(tenv, head(), tup<AType>(head()->loc, tenv.Fn, argsT, retT, 0));
 	c.constrain(tenv, this, retT);
 }
 
diff --git a/src/tuplr.hpp b/src/tuplr.hpp
index 61e3f41..0390435 100644
--- a/src/tuplr.hpp
+++ b/src/tuplr.hpp
@@ -289,6 +289,7 @@ struct AType : public ATuple {
 	AType(Cursor c, unsigned i) : ATuple(c), kind(VAR), id(i) {}
 	AType(Cursor c) : ATuple(c), kind(EXPR), id(0) {}
 	AType(Cursor c, AST* ast, va_list args) : ATuple(c, ast, args), kind(EXPR), id(0) {}
+	AType(const AType& copy) : ATuple(copy), kind(copy.kind), id(copy.id) {}
 	CVal compile(CEnv& cenv) { return NULL; }
 	const ATuple* prot() const { assert(kind == EXPR); return (*(begin() + 1))->to<const ATuple*>(); }
 	ATuple*       prot()       { assert(kind == EXPR); return (*(begin() + 1))->to<ATuple*>(); }
@@ -332,24 +333,21 @@ struct Subst : public list< pair<const AType*,AType*> > {
 				return j;
 		return end();
 	}
-	AST* apply(AST* ast) const {
-		AType* in = ast->to<AType*>();
-		if (!in) return ast;
+	AType* apply(const AType* in) const {
 		if (in->kind == AType::EXPR) {
 			AType* out = tup<AType>(in->loc, NULL);
-			for (ATuple::iterator i = in->begin(); i != in->end(); ++i)
-				out->push_back(apply(*i));
+			for (ATuple::const_iterator i = in->begin(); i != in->end(); ++i)
+				out->push_back(apply((*i)->as<AType*>()));
 			return out;
 		} else {
 			const_iterator i = find(in);
 			if (i != end()) {
-				AST*   out  = i->second;
-				AType* outT = out->to<AType*>();
-				if (outT && outT->kind == AType::EXPR && !outT->concrete())
-					out = apply(out);
+				AType* out = i->second->as<AType*>();
+				if (out->kind == AType::EXPR && !out->concrete())
+					out = apply(out->as<AType*>());
 				return out;
 			} else {
-				return in;
+				return new AType(*in);
 			}
 		}
 	}
@@ -547,7 +545,9 @@ inline ostream& operator<<(ostream& out, const Constraints& c) {
 
 /// Type-Time Environment
 struct TEnv : public Env<const ASymbol*, AType*> {
-	TEnv(PEnv& p) : penv(p), varID(1) {}
+	TEnv(PEnv& p) : penv(p), varID(1), Fn(new AType(penv.sym("Fn"))) {
+		Object::pool.addRoot(Fn);
+	}
 	AType* fresh(const ASymbol* sym) {
 		return def(sym, new AType(sym->loc, varID++));
 	}
@@ -573,9 +573,11 @@ struct TEnv : public Env<const ASymbol*, AType*> {
 
 	typedef map<const AST*, AType*> Vars;
 
-	Vars         vars;
-	PEnv&        penv;
-	unsigned     varID;
+	Vars     vars;
+	PEnv&    penv;
+	unsigned varID;
+
+	AType* Fn;
 };
 
 Subst unify(const Constraints& c);