From 000cbb0c810ad213fa70310d81fdc9afcb9643ee Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Marc=20Andr=C3=A9=20Tanner?= <mat@brain-dump.org>
Date: Sun, 19 Mar 2017 14:47:38 +0100
Subject: vis-lua: allow operators to be defined as lua functions

---
 vis-lua.c | 62 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 62 insertions(+)

(limited to 'vis-lua.c')

diff --git a/vis-lua.c b/vis-lua.c
index e76693c..4810d7f 100644
--- a/vis-lua.c
+++ b/vis-lua.c
@@ -267,6 +267,8 @@ static const void *func_ref_new(lua_State *L, int narg) {
 
 /* retrieve function from registry and place it at the top of the stack */
 static bool func_ref_get(lua_State *L, const void *addr) {
+	if (!addr)
+		return false;
 	lua_getfield(L, LUA_REGISTRYINDEX, "vis.functions");
 	lua_pushlightuserdata(L, (void*)addr);
 	lua_gettable(L, -2);
@@ -934,6 +936,64 @@ static int motion_register(lua_State *L) {
 	return 1;
 }
 
+/***
+ * Execute an operator.
+ *
+ * @function operator
+ * @tparam int id the id of the operator to execute
+ * @treturn bool whether the id was valid
+ * @local
+ */
+static int operator(lua_State *L) {
+	Vis *vis = obj_ref_check(L, 1, "vis");
+	enum VisOperator id = luaL_checkunsigned(L, 2);
+	// TODO handle var args?
+	lua_pushboolean(L, vis && vis_operator(vis, id));
+	return 1;
+}
+
+static size_t operator_lua(Vis *vis, Text *text, OperatorContext *c) {
+	lua_State *L = vis->lua;
+	if (!func_ref_get(L, c->context))
+		return EPOS;
+	File *file = vis->files;
+	while (file && (file->internal || file->text != text))
+		file = file->next;
+	if (!file || !obj_ref_new(L, file, VIS_LUA_TYPE_FILE))
+		return EPOS;
+	pushrange(L, &c->range);
+	pushpos(L, c->pos);
+	if (pcall(vis, L, 3, 1) != 0)
+		return EPOS;
+	return checkpos(L, -1);
+}
+
+/***
+ * Register a custom operator.
+ *
+ * @function operator_register
+ * @tparam function operator the Lua function implementing the operator
+ * @treturn int the associated operator id, or `-1` on failure
+ * @see operator, operator_new
+ * @local
+ * @usage
+ * -- custom operator replacing every 'a' with 'b'
+ * local id = vis:operator_register(function(file, range, pos)
+ * 	local data = file:content(range)
+ * 	data = data:gsub("a", "b")
+ * 	file:delete(range)
+ * 	file:insert(range.start, data)
+ * 	return range.start -- new cursor location
+ * end)
+ */
+static int operator_register(lua_State *L) {
+	Vis *vis = obj_ref_check(L, 1, "vis");
+	const void *func = func_ref_new(L, 2);
+	int id = vis_operator_register(vis, operator_lua, (void*)func);
+	lua_pushinteger(L, id);
+	return 1;
+}
+
 /***
  * Execute a text object.
  *
@@ -1297,6 +1357,8 @@ static const struct luaL_Reg vis_lua[] = {
 	{ "info", info },
 	{ "message", message },
 	{ "map", map },
+	{ "operator", operator },
+	{ "operator_register", operator_register },
 	{ "motion", motion },
 	{ "motion_register", motion_register },
 	{ "textobject", textobject },
-- 
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