From acf13b1df559c6187d270ef7e31890201c191b12 Mon Sep 17 00:00:00 2001
From: David Robillard <d@drobilla.net>
Date: Thu, 9 Dec 2010 17:58:43 +0000
Subject: Add let form.

git-svn-id: http://svn.drobilla.net/resp/resp@328 ad02d1e2-f140-0410-9f75-f8b11f17cedd
---
 src/lift.cpp | 34 +++++++++++++++++++++++++++++++++-
 1 file changed, 33 insertions(+), 1 deletion(-)

(limited to 'src/lift.cpp')

diff --git a/src/lift.cpp b/src/lift.cpp
index ad377d7..e3a741b 100644
--- a/src/lift.cpp
+++ b/src/lift.cpp
@@ -32,7 +32,7 @@ lift_symbol(CEnv& cenv, Code& code, const ASymbol* sym) throw()
 {
 	if (!cenv.liftStack.empty() && cenv.name(cenv.liftStack.top().fn) == sym->sym()) {
 		return cenv.penv.sym("_me"); // Reference to innermost function
-	} else if (!cenv.code.innermost(sym)) {
+	} else if (!cenv.liftStack.empty() && !cenv.code.innermost(sym)) {
 		// Replace symbol with code to access free variable from closure
 		const int32_t index = cenv.liftStack.top().index(sym);
 		return tup<ATuple>(sym->loc, cenv.penv.sym("."),
@@ -157,6 +157,36 @@ lift_fn(CEnv& cenv, Code& code, const ATuple* fn) throw()
 	return cons;
 }
 
+static const AST*
+lift_let(CEnv& cenv, Code& code, const ATuple* let) throw()
+{
+	const ATuple* vars = let->list_ref(1)->to_tuple();
+	
+	List<ATuple, const AST> copy(let->loc, let->head(), NULL);
+	List<ATuple, const AST> copyVars;
+	
+	cenv.push();
+	
+	for (ATuple::const_iterator i = vars->begin(); i != vars->end();) {
+		const ASymbol* sym = (*i++)->to_symbol();
+		const AST*     val = (*i++);
+		cenv.def(sym, val, cenv.type(val), NULL);
+		copyVars.push_back(sym);
+		copyVars.push_back(val);
+		resp_lift(cenv, code, val);
+	}
+	copy.push_back(copyVars);
+
+	for (ATuple::const_iterator i = let->iter_at(2); i != let->end(); ++i)
+		copy.push_back(resp_lift(cenv, code, *i));
+
+	cenv.pop();
+	
+	cenv.setTypeSameAs(copy, let);
+	
+	return copy;
+}
+
 static const AST*
 lift_call(CEnv& cenv, Code& code, const ATuple* call) throw()
 {
@@ -246,6 +276,8 @@ resp_lift(CEnv& cenv, Code& code, const AST* ast) throw()
 			return lift_fn(cenv, code, call);
 		else if (form == "if")
 			return lift_args(cenv, code, call);
+		else if (form == "let")
+			return lift_let(cenv, code, call);
 		else if (form == "match")
 			return call; // FIXME
 		else
-- 
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