vimscript 文件检测

func! CompileRunGpp()
exec "w"
let temp = "/home/darkdream/problem/exe/ "            "后面留一个空格以便替换
let outfilename=substitute(temp," ",expand("%<"),‘g‘)   “将空格替换成文件名去后缀
if filereadable(substitute("/home/darkdream/problem/exe/ "," ",expand("%<"),‘g‘))   ”检测文件是否存在
silent exec "! rm ".outfilename   “删除文件
endif
silent exec "!g++ % -o /home/darkdream/problem/exe/%<"  
exec "! /home/darkdream/problem/exe/%<"   ”编译运行文件
endfunc