From bf757dcc9b66ebb3bf7e2df8e8c7d3a011ddd6dc Mon Sep 17 00:00:00 2001
From: David Robillard <d@drobilla.net>
Date: Tue, 25 Dec 2012 00:09:34 +0000
Subject: Preliminary syntax-rules macro implementation.

git-svn-id: http://svn.drobilla.net/resp/trunk@443 ad02d1e2-f140-0410-9f75-f8b11f17cedd
---
 src/resp.hpp | 33 +++++++++++++++++++++++++++++++--
 1 file changed, 31 insertions(+), 2 deletions(-)

(limited to 'src/resp.hpp')

diff --git a/src/resp.hpp b/src/resp.hpp
index e572473..fd861aa 100644
--- a/src/resp.hpp
+++ b/src/resp.hpp
@@ -490,6 +490,17 @@ ostream& operator<<(ostream& out, const Env<V>& env) {
  * Parser: S-Expressions (SExp) -> AST Nodes (AST)                         *
  ***************************************************************************/
 
+struct Macro {
+	struct Rule {
+		Rule(const ATuple* p, const ATuple* t) : pattern(p), templ(t) {}
+		const ATuple* pattern;
+		const ATuple* templ;
+	};
+
+	std::set<std::string> keywords;
+	std::list<Rule>       rules;
+};
+
 /// Parse Time Environment (really just a symbol table)
 struct PEnv : private map<const string, const char*> {
 	PEnv() : symID(0) {}
@@ -514,6 +525,9 @@ struct PEnv : private map<const string, const char*> {
 	typedef std::set<std::string> Primitives;
 	Primitives primitives;
 
+	typedef std::map<const std::string, Macro> Macros;
+	Macros macros;
+
 	unsigned symID;
 };
 
@@ -528,6 +542,11 @@ struct Constraint : public pair<const AST*,const AST*> {
 		: pair<const AST*, const AST*>(a, b) {}
 };
 
+static inline bool
+is_dots(const AST* exp) {
+	return (exp->to_symbol() && exp->as_symbol()->str() == "...");
+}
+
 /// Type substitution
 struct Subst : public list<Constraint> {
 	Subst(const AST* s=0, const AST* t=0) {
@@ -550,8 +569,18 @@ struct Subst : public list<Constraint> {
 			if (in->as_tuple()->empty())
 				return in;
 			List out;
-			for (ATuple::const_iterator i = in->as_tuple()->begin(); i != in->as_tuple()->end(); ++i)
-				out.push_back(apply(*i));
+			for (auto i : *in->as_tuple()) {
+				if (is_dots(i)) {
+					const_iterator o = find(i);
+					if (o != end()) {
+						for (auto j : *o->second->as_tuple()) {
+							out.push_back(apply(j));
+						}
+					}
+				} else {
+					out.push_back(apply(i));
+				}
+			}
 			if (out.head)
 				out.head->loc = in->loc;
 			return out.head;
-- 
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