Convert match form to if at lift stage (remove knowledge of match from compile stage and backends).

git-svn-id: http://svn.drobilla.net/resp/resp@342 ad02d1e2-f140-0410-9f75-f8b11f17cedd

1 files changed, 11 insertions, 22 deletions

diff --git a/src/compile.cpp b/src/compile.cpp
index b5d7222..123b403 100644
--- a/src/compile.cpp
+++ b/src/compile.cpp
@@ -57,7 +57,7 @@ compile_dot(CEnv& cenv, const ATuple* dot) throw()
 	const ALiteral<int32_t>* index = (ALiteral<int32_t>*)(*++i);
 	assert(index->tag() == T_INT32);
 	CVal tupVal = resp_compile(cenv, tup);
-	return cenv.engine()->compileDot(cenv, tupVal, index->val + 1); // + 1 to skip RTTI
+	return cenv.engine()->compileDot(cenv, tupVal, index->val);
 }
 
 static CVal
@@ -120,7 +120,10 @@ compile_if(CEnv& cenv, const ATuple* aif) throw()
 		i = next; // jump 2 each iteration (to the next predicate)
 	}
 
-	CVal elseV = resp_compile(cenv, aif->list_last());
+	CVal elseV = NULL;
+	if (*aif->list_last() != *cenv.penv.sym("__unreachable"))
+		elseV = resp_compile(cenv, aif->list_last());
+
 	return cenv.engine()->compileIfEnd(cenv, state, elseV, cenv.type(aif));
 }
 
@@ -147,25 +150,11 @@ compile_let(CEnv& cenv, const ATuple* let) throw()
 }
 
 static CVal
-compile_match(CEnv& cenv, const ATuple* match) throw()
+compile_tag_is(CEnv& cenv, const ATuple* call) throw()
 {
-	IfState     state   = cenv.engine()->compileIfStart(cenv);
-	CVal        matchee = resp_compile(cenv, match->list_ref(1));
-	CVal        rtti    = cenv.engine()->compileDot(cenv, matchee, 0);
-
-	size_t idx = 1;
-	for (ATuple::const_iterator i = match->iter_at(2); i != match->end(); ++idx) {
-		const AST*     pat  = *i++;
-		const AST*     body = *i++;
-		const ASymbol* sym  = pat->as_tuple()->head()->as_symbol();
-
-		CVal condV = cenv.engine()->compileIsA(cenv, rtti, sym);
-
-		cenv.engine()->compileIfBranch(cenv, state, condV, body);
-	}
-
-	const AType* type  = cenv.type(match);
-	return cenv.engine()->compileIfEnd(cenv, state, NULL, type);
+	const AST*     lhs = call->list_ref(1);
+	const ASymbol* rhs = call->list_ref(2)->as_symbol();
+	return cenv.engine()->compileIsA(cenv, resp_compile(cenv, lhs), rhs);
 }
 
 static CVal
@@ -235,8 +224,8 @@ resp_compile(CEnv& cenv, const AST* ast) throw()
 			return compile_if(cenv, call);
 		else if (form == "let")
 			return compile_let(cenv, call);
-		else if (form == "match")
-			return compile_match(cenv, call);
+		else if (form == "__tag_is")
+			return compile_tag_is(cenv, call);
 		else
 			return compile_call(cenv, call);
 	}