E.g.

    /usr/src/cmd/sh/mac.h:
    #define IF      if(
    #define THEN    ){
    #define ELSE    } else {
    #define ELIF    } else if (
    #define FI      ;}
    
    #define BEGIN   {
    #define END     }
    #define SWITCH  switch(
    #define IN      ){
    #define ENDSW   }
    #define FOR     for(
    #define WHILE   while(