From a726e45ec81e2cc8512f9e4c5b1459a86ab53098 Mon Sep 17 00:00:00 2001
From: Thijs Schreijer <thijs@thijsschreijer.nl>
Date: Tue, 12 Nov 2013 16:14:21 +0100
Subject: Several updates: 1) will search the system path for Lua interpreter
 if no location is found. Only then the ancient defaults will be checked. 2)
 if /LUA is provided, it will only look there, and fail if not found instead
 of falling back to the defaults 3) if no interpreter found, it is not
 automatically installed. Only with explicit /L switch the included
 interpreter is installed

---
 install.bat | 69 +++++++++++++++++++++++++++++++++++++++++++++++++++++--------
 1 file changed, 60 insertions(+), 9 deletions(-)

diff --git a/install.bat b/install.bat
index f6601aa8..c085de40 100644
--- a/install.bat
+++ b/install.bat
@@ -41,6 +41,32 @@ local function die(message)
 	os.exit(1)
 end
 
+function split_string(str, delim, maxNb)
+	-- Eliminate bad cases...
+	if string.find(str, delim) == nil then
+		return { str }
+	end
+	if maxNb == nil or maxNb < 1 then
+		maxNb = 0	 -- No limit
+	end
+	local result = {}
+	local pat = "(.-)" .. delim .. "()"
+	local nb = 0
+	local lastPos
+	for part, pos in string.gmatch(str, pat) do
+		nb = nb + 1
+		result[nb] = part
+		lastPos = pos
+		if nb == maxNb then break end
+	end
+	-- Handle the last field
+	if nb ~= maxNb then
+		result[nb + 1] = string.sub(str, lastPos)
+	end
+	return result
+end
+
+
 local function exec(cmd)
 	--print(cmd)
 	local status = os.execute(cmd)
@@ -180,6 +206,7 @@ end
 -- ***********************************************************
 local function look_for_interpreter (directory)
 	if vars.LUA_BINDIR then
+        -- if LUA_BINDIR is specified, it must be there, otherwise we fail
 		if exists( S"$LUA_BINDIR\\lua$LUA_VERSION.exe" ) then
 			vars.LUA_INTERPRETER = S"lua$LUA_VERSION.exe"
 			print(S"       Found $LUA_BINDIR\\$LUA_INTERPRETER")
@@ -309,9 +336,31 @@ end
 
 local function look_for_lua_install ()
 	print("Looking for Lua interpreter")
-	local directories = { [[c:\lua5.1.2]], [[c:\lua]], [[c:\kepler\1.1]] }
+	local directories
 	if vars.LUA_PREFIX then
-		table.insert(directories, 1, vars.LUA_PREFIX)
+		directories = { vars.LUA_PREFIX }
+	else
+		-- no prefix given, so use path
+		directories = (os.getenv("PATH",";") or "")
+		local i = 1
+        while i ~= 0 do directories, i = directories:gsub(";;",";") end  --remove all doubles
+		directories = split_string(directories,";")
+		-- if a path element ends with "\bin\" then remove it, as the searcher will check there anyway
+		for i, val in ipairs(directories) do
+			-- remove trailing backslash
+			while val:sub(-1,-1) == "\\" and val:sub(-2,-1) ~= ":\\" do 
+				val = val:sub(1,-2)
+			end
+			-- remove trailing 'bin'
+			if val:upper():sub(-4,-1) == "\\BIN" or val:upper():sub(-4,-1) == ":BIN" then
+				val = val:sub(1,-5)
+			end
+			directories[i] = val
+		end
+		-- finaly add some other default paths
+		table.insert(directories, [[c:\lua5.1.2]])
+		table.insert(directories, [[c:\lua]])
+		table.insert(directories, [[c:\kepler\1.1]])
 	end
 	if vars.LUA_BINDIR and vars.LUA_LIBDIR and vars.LUA_INCDIR then
 		if look_for_interpreter(vars.LUA_BINDIR) and 
@@ -397,13 +446,10 @@ vars.LUADIR = S"$FULL_PREFIX\\lua"
 vars.INCDIR = S"$FULL_PREFIX\\include"
 vars.LUA_SHORTV = vars.LUA_VERSION:gsub("%.", "")
 
-if not look_for_lua_install() then
-	print("Could not find Lua. Will install its own copy.")
-	print("See /? for options for specifying the location of Lua.")
+if INSTALL_LUA then
 	if vars.LUA_VERSION ~= "5.1" then
 		die("Cannot install own copy because no 5.2 version is bundled")
 	end
-	INSTALL_LUA = true
 	vars.LUA_INTERPRETER = "lua5.1"
 	vars.LUA_BINDIR = vars.BINDIR
 	vars.LUA_LIBDIR = vars.LIBDIR
@@ -412,8 +458,13 @@ if not look_for_lua_install() then
     vars.LUA_RUNTIME = "MSVCR80"
     vars.UNAME_M = "x86"
 else
-    vars.UNAME_M = get_architecture()
-	print(S[[
+	if not look_for_lua_install() then
+		die("Could not find Lua. See /? for options for specifying the location of Lua, or installing a bundled copy of Lua 5.1.")
+	end
+    vars.UNAME_M = get_architecture()  -- can only do when installation was found
+end
+
+print(S[[
 
 Will configure LuaRocks with the following paths:
 LuaRocks       : $FULL_PREFIX
@@ -425,7 +476,7 @@ Binaries will be linked against: $LUA_LIBNAME with runtime $LUA_RUNTIME
 System architecture detected as: $UNAME_M
 
 ]])
-end
+
 
 -- ***********************************************************
 -- Install LuaRocks files
-- 
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