Print line number of 1 instead of 0 if buf.ls or buf.rs is not set.

Author: Lethja

demo/xtra/DIFF.LUA

@@ -1,4 +1,4 @@
-#!/usr/bin/env lua
+#!/usr/bin/env lua
 
 local function diff_u(fn1,fn2)
 	local function open(fn) local f, e = io.open(fn) if not f then print(e) os.exit(1) end return f end
@@ -17,8 +17,8 @@ local function diff_u(fn1,fn2)
 	local function flush_buf()
 		if #buf.line > 0 then
 			buf.del, buf.add = #buf.line - buf.add - p1, #buf.line - buf.del - p2
-			local header = "@@ -" .. (buf.ls or "0") .. (buf.del == 1 and "" or "," .. buf.del) ..
-					" +" .. (buf.rs or "0") .. (buf.add == 1 and "" or "," .. buf.add) .. " @@"
+			local header = "@@ -" .. (buf.ls or "1") .. (buf.del == 1 and "" or "," .. buf.del) ..
+					" +" .. (buf.rs or "1") .. (buf.add == 1 and "" or "," .. buf.add) .. " @@"
 			table.insert(buf.line, 1, header)
 			for _, v in ipairs(buf.line) do print(v) end
 		end