TCL字符串前置

Question

只是一个简单但经常需要的操作 - 如何将字符串添加到变量:

set s "world!!!"
prepend s "Hello " #how to accomplish this effectively?
puts $s
#should print "Hello world!!!"

Answer 1

你可以写一个程序prepend:

proc prepend {s_var txt} {
  upvar 1 $s_var s
  set s "${txt}${s}"
}

这正是你想要的.但我认为通常写起来更简单:

set s "Hello ${s}"