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Comment by johndoe0815

4 years ago

Steve Bourne used a set of macros to enable ALGOL-like programming in C and used it to implement his Unix shell - https://research.swtch.com/shmacro

18 comments

johndoe0815

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OskarS  4 years ago

This is obviously terrible, but my favorite part of this whole thing is the fact that he included the parentheses in the IF/THEN macros, so you didn't have to do it for the condition in the if statement. So, like, this line doesn't need parentheses around the condition:

    IF (n=to-from)<=1 THEN return FI

All modern languages that try and do a refresh on the C style (Rust and Swift notably) do this, it's clearly the right idea. They should just update the C and C++ syntax to make those parentheses optional at this point.

(PS. some people would also recoil at the assignment-as-expression used in that line, but that's just good clean fun!)

  • josefx  4 years ago

    They already make them optional for single nested statements, which causes a gigantic mess when you extend code and forget to add them.

       if (a)
       doThis();
       andThat();

    is interpreted as

        if(a){
      doThis();
    }
    andThat();

    Some compilers are nice enough to throw around misleading indentation warnings, but without an explicit block termination like FI this just causes issues all over the place.

agumonkey  4 years ago

ha, I was googling FORTRAN C macros and went nowhere, that was the page I was looking for :)