Add a source module for whitespace checking

Author: n1tehawk

install.lua

@@ -117,7 +117,8 @@ for _, filename in ipairs {
       "fs.lua",
       "globbing.lua",
       "utils.lua",
-      "argparse.lua"} do
+      "argparse.lua",
+      "whitespace.lua"} do
    copy("src" .. dirsep .. "luacheck" .. dirsep .. filename, luacheck_lib_dir)
 end
 

luacheck-scm-1.rockspec

@@ -40,7 +40,8 @@ build = {
       ["luacheck.fs"] = "src/luacheck/fs.lua",
       ["luacheck.globbing"] = "src/luacheck/globbing.lua",
       ["luacheck.utils"] = "src/luacheck/utils.lua",
-      ["luacheck.argparse"] = "src/luacheck/argparse.lua"
+      ["luacheck.argparse"] = "src/luacheck/argparse.lua",
+      ["luacheck.whitespace"] = "src/luacheck/whitespace.lua"
    },
    install = {
       bin = {

src/luacheck/whitespace.lua

@@ -0,0 +1,41 @@
+local utils = require "luacheck.utils"
+
+local function check_whitespace(chstate, src --[[, code_lines]])
+   for lineno, line in ipairs(utils.split(src, "\n")) do
+      line = string.gsub(line, "\r$", "") -- strip any remaining CR line ending
+      if line ~= "" then
+         local from, to = line:find("%s+$")
+         if from then
+            if from == 1 then
+               -- line contains only whitespace (thus never considered "code")
+               chstate:warn({code = "611",
+                             line = lineno, column = from, end_column = to})
+            --[[ (This needs to be reworked.)
+            elseif code_lines[lineno] then
+               -- trailing whitespace on code line
+               chstate:warn({code = "612",
+                             line = lineno, column = from, end_column = to})
+            else
+               -- trailing whitespace on non-code line
+               chstate:warn({code = "613",
+                             line = lineno, column = from, end_column = to})
+            end
+            --]]
+            else
+               -- line contains trailing whitespace
+               chstate:warn({code = "612",
+                             line = lineno, column = from, end_column = to})
+            end
+         else
+            from, to = line:find("^%s+")
+            if from and string.find(line:sub(1, to), " \t", 1, true) then
+               -- inconsistent leading whitespace (SPACE followed by TAB)
+               chstate:warn({code = "621",
+                             line = lineno, column = from, end_column = to})
+            end
+         end
+      end
+   end
+end
+
+return check_whitespace