Static Foreach

[nazo]

I want to write like this code for optimize. The compiler cannot 
optimize code like this code. CGI needs more speeds!

char[] replace(char[][] before,char[][] after)(char[] str){
   static assert(before.length==after.length);
   compile char[][] t=before;
   compile char[][] u=after;
   /*sort*/
   static for(compile int i;i<t.length-1;i++)
     static for(compile int j=j+1;j<t.length;j++)
       static if(t[i]>t[j]){
         compile char[] tmp=t[i];
         t[i]=t[j];
         t[j]=tmp;
         compile char[] tmp=u[i];
         t[i]=u[j];
         u[j]=tmp;
       }
   /**/
   int len=str.length;
   compile before_len=0;
   for(int i;i<str.length-b[0].length;i++){
     static foreach(compile int j,compile char[] b;t){
       static if(before_len!=b.length){
         if(b.length>len)
           return str;
       }
       if(str[i..i+b.length]==b){
         str=str[0..i]~u[j]~str[i+b.length..$];
         i+=u[j].length-1;
         len-=u[j].length;
         break;/*for*/
       }
       before_len=b.length;
     }
     len--;
   }
   return str;
}

private import std.stdio;
void main(char[][] args){
   if(args.length<2)return -1;
   writefln(replace!(["aa","bb"],["cc","dd"])(args[1]));
}