From 47e82949164c23973dbad72d3982d9aef557d118 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Marc=20Andr=C3=A9=20Tanner?= <mat@brain-dump.org>
Date: Sat, 5 Nov 2016 16:28:59 +0100
Subject: vis: display Lua package.cpath in :help output

These paths are used to load the Lua LPeg module (lpeg.so)
and are thus helpful when diagnosing setup problems in case
syntax highlighting does not work.
---
 vis-cmds.c | 27 ++++++++++++++++-----------
 vis-lua.c  | 14 ++++++++++----
 vis-lua.h  |  6 ++++--
 3 files changed, 30 insertions(+), 17 deletions(-)

diff --git a/vis-cmds.c b/vis-cmds.c
index 87ebd67..ab4a4d2 100644
--- a/vis-cmds.c
+++ b/vis-cmds.c
@@ -653,18 +653,23 @@ static bool cmd_help(Vis *vis, Win *win, Command *cmd, const char *argv[], Curso
 		"(prefix with C-, S-, and M- for Ctrl, Shift and Alt respectively)\n\n");
 	print_symbolic_keys(vis, txt);
 
-	const char *paths = vis_lua_paths_get(vis);
-	if (paths) {
-		char *copy = strdup(paths);
-		text_appendf(txt, "\n Lua paths used to load runtime files "
-			"(? will be replaced by filename):\n\n");
-		for (char *elem = copy, *next; elem; elem = next) {
-			if ((next = strstr(elem, ";")))
-				*next++ = '\0';
-			if (*elem)
-				text_appendf(txt, "  %s\n", elem);
+	char *paths[] = { NULL, NULL };
+	char *paths_description[] = {
+		"Lua paths used to load runtime files (? will be replaced by filename):",
+		"Lua paths used to load C libraries (? will be replaced by filename):",
+	};
+
+	if (vis_lua_paths_get(vis, &paths[0], &paths[1])) {
+		for (size_t i = 0; i < LENGTH(paths); i++) {
+			text_appendf(txt, "\n %s\n\n", paths_description[i]);
+			for (char *elem = paths[i], *next; elem; elem = next) {
+				if ((next = strstr(elem, ";")))
+					*next++ = '\0';
+				if (*elem)
+					text_appendf(txt, "  %s\n", elem);
+			}
+			free(paths[i]);
 		}
-		free (copy);
 	}
 
 	text_save(txt, NULL);
diff --git a/vis-lua.c b/vis-lua.c
index 7f045fa..8431111 100644
--- a/vis-lua.c
+++ b/vis-lua.c
@@ -123,7 +123,7 @@ static void window_status_update(Vis *vis, Win *win) {
 #if !CONFIG_LUA
 
 bool vis_lua_path_add(Vis *vis, const char *path) { return true; }
-const char *vis_lua_paths_get(Vis *vis) { return NULL; }
+bool vis_lua_paths_get(Vis *vis, const char **lpath, const char **cpath) { return false; }
 void vis_lua_init(Vis *vis) { }
 void vis_lua_start(Vis *vis) { }
 void vis_lua_quit(Vis *vis) { }
@@ -1343,13 +1343,19 @@ bool vis_lua_path_add(Vis *vis, const char *path) {
 	return true;
 }
 
-const char *vis_lua_paths_get(Vis *vis) {
+bool vis_lua_paths_get(Vis *vis, char **lpath, char **cpath) {
 	lua_State *L = vis->lua;
 	if (!L)
-		return NULL;
+		return false;
+	const char *s;
 	lua_getglobal(L, "package");
 	lua_getfield(L, -1, "path");
-	return lua_tostring(L, -1);
+	s = lua_tostring(L, -1);
+	*lpath = s ? strdup(s) : NULL;
+	lua_getfield(L, -2, "cpath");
+	s = lua_tostring(L, -1);
+	*cpath = s ? strdup(s) : NULL;
+	return true;
 }
 
 static bool package_exist(Vis *vis, lua_State *L, const char *name) {
diff --git a/vis-lua.h b/vis-lua.h
index 644ce73..9732735 100644
--- a/vis-lua.h
+++ b/vis-lua.h
@@ -13,8 +13,10 @@ typedef struct lua_State lua_State;
 
 /* add a directory to consider when loading lua files */
 bool vis_lua_path_add(Vis*, const char *path);
-/* get semi colon separated list of paths to load lua files */
-const char *vis_lua_paths_get(Vis*);
+/* get semicolon separated list of paths to load lua files
+ * (*lpath = package.path) and Lua C modules (*cpath = package.cpath)
+ * both these pointers need to be free(3)-ed by the caller */
+bool vis_lua_paths_get(Vis*, char **lpath, char **cpath);
 
 /* various event handlers, triggered by the vis core */
 void vis_lua_init(Vis*);
-- 
cgit v1.2.3