1 files changed, 35 insertions, 9 deletions

@@ -48,17 +48,43 @@ function m.procedure (params, body, env)
         return setmetatable(t, mt)
 end
 
-local specials = {
 m.specials = {
         -- each of these takes R (a list of args) and E (an environment)
-        quote =
-                function (r, e) return r[1] end,
-        define =
-                function (r, e) rawset(e, r[1], m.eval(r[2][1], e)) end,
-        lambda =
-                function (r, e) return m.procedure(r[1], r[2], e) end,
-        ["set!"] =
-                function (r, e) e[r[1]] = m.eval(r[2][1], e) end,
+        quote = function (r, e) return r[1] end,
+        quasiquote =
+                function (r, e)
+                        local x = r[1]
+                        if not type.islist(x) or x == type.null then
+                                return x
+                        end
+                        local QQ, fin = {}, nil
+                        local car, cdr = x[1], x[2]
+                        while cdr do
+                                if type.islist(car) then
+                                        if car[1] == "unquote" then
+                                                table.insert(QQ,
+                                                        m.eval(car[2][1], e))
+                                        elseif car[1] == "unquote-splicing" then
+                                                local usl = m.eval(car[2][1], e)
+                                                if not type.islist(usl) then
+                                                        fin = usl
+                                                        break
+                                                end
+                                                while usl[2] do
+                                                        table.insert(QQ, usl[1])
+                                                        usl = usl[2]
+                                                end
+                                        end
+                                else
+                                        table.insert(QQ, car)
+                                end
+                                car, cdr = cdr[1], cdr[2]
+                        end
+                        return type.list(QQ, fin)
+                end,
+        define = function (r, e) rawset(e, r[1], m.eval(r[2][1], e)) end,
+        lambda = function (r, e) return m.procedure(r[1], r[2], e) end,
+        ["set!"] = function (r, e) e[r[1]] = m.eval(r[2][1], e) end,
         ["if"] =
                 function (r, e)
                         local test, conseq, alt =