Add quote form, to allow expressions literal symbols and lists (lists not yet implemented).

Quoting is a thin lexical concept - a quote of a symbol/list compiles to a symbol/list,
rather than interpreted as code (i.e. a variable/call, respectively).  A quote of anything
else is equivalent to its quotee, e.g. a quote of a String is simply that string (the quote
is removed at an early stage by the compiler).  There is no Quote data type, or explicit
unquoting, or anything like that.


git-svn-id: http://svn.drobilla.net/resp/resp@365 ad02d1e2-f140-0410-9f75-f8b11f17cedd

1 files changed, 13 insertions, 0 deletions

diff --git a/src/constrain.cpp b/src/constrain.cpp
index 4bd6c08..f65ad8f 100644
--- a/src/constrain.cpp
+++ b/src/constrain.cpp
@@ -260,6 +260,17 @@ constrain_match(TEnv& tenv, Constraints& c, const ATuple* call) throw(Error)
 }
 
 static void
+constrain_quote(TEnv& tenv, Constraints& c, const ATuple* call) throw(Error)
+{
+	THROW_IF(call->list_len() != 2, call->loc, "`quote' requires exactly 1 argument");
+	switch (call->list_ref(1)->tag()) {
+	case T_TUPLE:  c.constrain(tenv, call, tenv.named("List"));   return;
+	case T_SYMBOL: c.constrain(tenv, call, tenv.named("Symbol")); return;
+	default: return;
+	}
+}
+
+static void
 constrain_call(TEnv& tenv, Constraints& c, const ATuple* call) throw(Error)
 {
 	const AST* const head = call->head();
@@ -370,6 +381,8 @@ constrain_list(TEnv& tenv, Constraints& c, const ATuple* tup) throw(Error)
 		constrain_let(tenv, c, tup);
 	else if (form == "match")
 		constrain_match(tenv, c, tup);
+	else if (form == "quote")
+		constrain_quote(tenv, c, tup);
 	else
 		constrain_call(tenv, c, tup);
 }