vis-lua: expose register names as vis:register_names()

1 files changed, 38 insertions, 1 deletions

diff --git a/vis-lua.c b/vis-lua.c
index 7e03c65..9936219 100644
--- a/vis-lua.c
+++ b/vis-lua.c
@@ -632,6 +632,42 @@ static int mark_names_iter(lua_State *L) {
 }
 
 /***
+ * Create an iterator over all register names.
+ * @function register_names
+ * @return the new iterator
+ * @usage
+ * for reg in vis:register_names() do
+ * 	local value = vis.registers[reg]
+ * 	if value then
+ * 		-- do something with register value
+ * 	end
+ * end
+ */
+static int register_names_iter(lua_State *L);
+static int register_names(lua_State *L) {
+	enum VisRegister *handle = lua_newuserdata(L, sizeof *handle);
+	*handle = 0;
+	lua_pushcclosure(L, register_names_iter, 1);
+	return 1;
+}
+
+static int register_names_iter(lua_State *L) {
+	char reg = '\0';
+	enum VisRegister *handle = lua_touserdata(L, lua_upvalueindex(1));
+	if (*handle < LENGTH(vis_registers))
+		reg = vis_registers[*handle].name;
+	else if (VIS_REG_a <= *handle && *handle <= VIS_REG_z)
+		reg = 'a' + *handle - VIS_REG_a;
+	if (reg) {
+		char name[2] = { reg, '\0' };
+		lua_pushstring(L, name);
+		(*handle)++;
+		return 1;
+	}
+	return 0;
+}
+
+/***
  * Execute a `:`-command.
  * @function command
  * @tparam string command the command to execute
@@ -1022,6 +1058,7 @@ static const struct luaL_Reg vis_lua[] = {
 	{ "files", files },
 	{ "windows", windows },
 	{ "mark_names", mark_names },
+	{ "register_names", register_names },
 	{ "command", command },
 	{ "info", info },
 	{ "message", message },
@@ -1054,7 +1091,7 @@ static int registers_index(lua_State *L) {
 		goto err;
 	size_t len;
 	const char *value = vis_register_get(vis, reg, &len);
-	lua_pushlstring(L, value, len);
+	lua_pushlstring(L, value ? value : "" , len);
 	return 1;
 err:
 	lua_pushnil(L);