added less severe failure conditions to shutil, luash should crash less now.

modules/lib/shutil.lua

@@ -10,17 +10,22 @@ function shutil.genenv()
 end
 function loadfile(fn)
  local f=io.open(fn,"rb")
+ if not f then return false, "cannot read file" end
  local S=f:read("*a")
  f:close()
  return load(S,"=("..fn..")","bt",os.genenv())
 end
 function run(fn,...)
- local r = {pcall(loadfile(fn),...)}
+ local lf = loadfile(fn)
+ if not lf then return false, "cannot load file" end
+ local r = {pcall(lf,...)}
  if r[1] == true then
   table.remove(r,1)
  end
  print(table.unpack(r))
 end
 function srun(fn,...)
- spawn(fn,print(pcall(loadfile(fn),...)))
+ local lf = loadfile(fn)
+ if not lf then return false, "cannot load file" end
+ spawn(fn,print(pcall(lf,...)))
 end