From 594370a2a381545aea8d0631a86f422f84ee2792 Mon Sep 17 00:00:00 2001
From: David Robillard <d@drobilla.net>
Date: Thu, 19 Aug 2010 22:34:22 +0000
Subject: Generalise `cons': a call to any symbol beginning with an uppercase
 character (i.e. a type symbol), e.g. (Thing 2), is a call to a type
 constructor which creates a Tup containing the arguments, with the symbol as
 the first element in the type expression, e.g. (Thing 2) has type (Thing Int)
 and compiles to a tuple containing a single Int.

The type constructor `Tup' can be used as a `cons' replacement to construct
generic tuples.


git-svn-id: http://svn.drobilla.net/resp/resp@264 ad02d1e2-f140-0410-9f75-f8b11f17cedd
---
 src/parse.cpp | 33 +++++++++++++++++++++++----------
 1 file changed, 23 insertions(+), 10 deletions(-)

(limited to 'src/parse.cpp')

diff --git a/src/parse.cpp b/src/parse.cpp
index 3184f8a..7482039 100644
--- a/src/parse.cpp
+++ b/src/parse.cpp
@@ -37,18 +37,32 @@ PEnv::parse(const AST* exp)
 {
 	const ATuple* tup = exp->to<const ATuple*>();
 	if (tup) {
-		if (tup->empty()) throw Error(exp->loc, "call to empty list");
-		if (!tup->head()->to<const ATuple*>()) {
-			MF mf = mac(*tup->head()->to<const ALexeme*>());
-			const AST*    expanded     = (mf ? mf(*this, exp) : exp);
-			const ATuple* expanded_tup = expanded->to<const ATuple*>();
-			const PEnv::Handler* h = handler(true, *expanded_tup->head()->to<const ALexeme*>());
+		THROW_IF(tup->empty(), exp->loc, "Call to empty list");
+		const ALexeme* form = tup->head()->to<const ALexeme*>();
+		if (form) {
+			MF mf = mac(*form);
+			if (mf) {
+				exp = mf(*this, exp)->as<ATuple*>(); // Apply macro
+				tup = exp->to<const ATuple*>();
+			}
+		}
+	}
+	
+	if (tup) {
+		THROW_IF(tup->empty(), exp->loc, "Call to empty list");
+		const ALexeme* form = tup->head()->to<const ALexeme*>();
+		if (form) {
+			const PEnv::Handler* h = handler(true, *form);
 			if (h)
-				return h->func(*this, expanded, h->arg);
+				return h->func(*this, exp, h->arg); // Parse special form
+
+			if (isupper(form->c_str()[0])) // Call constructor (any uppercase symbol)
+				return new ACons(parseTuple(*this, tup));
 		}
-		ATuple* parsed_tup = parseTuple(*this, tup);
-		return new ACall(parsed_tup); // Parse as regular call
+			
+		return new ACall(parseTuple(*this, tup)); // Parse regular call
 	}
+
 	const ALexeme* lex = exp->to<const ALexeme*>();
 	assert(lex);
 	if (isdigit((*lex)[0])) {
@@ -177,7 +191,6 @@ initLang(PEnv& penv, TEnv& tenv)
 	penv.reg(true, "fn",    PEnv::Handler(parseFn));
 	penv.reg(true, "quote", PEnv::Handler(parseQuote));
 	penv.reg(true, "if",    PEnv::Handler(parseCall<AIf>));
-	penv.reg(true, "cons",  PEnv::Handler(parseCall<ACons>));
 	penv.reg(true, ".",     PEnv::Handler(parseCall<ADot>));
 	penv.reg(true, "def",   PEnv::Handler(parseCall<ADef>));
 
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