3 ms·

> No, but calling a function with arguments of the wrong type is something tests would catch. Or the compiler.

• rbanffy 15y ago
  A compiler can only go so far. It'll happily compile: #include <stdio.h> int main(int argc, char *argv[]) { FILE *fp = fopen("outfile", "w"); fclose(fp); do_something(fp); return 0; } int do_something(FILE *f) { fprintf(f, "This should work if you know what you're doing"); } And it won't work.
  • maximilianburke 15y ago
    In C++, proper scoping with RAII (similar to CL's with-blah idioms) would alleviate that issue as do_something in the code below won't compile. struct WithOpenFile { FILE *fp; WithOpenFile(const char *fileName) : fp(fopen(fileName, "w")) {} ~WithOpenFile() { fclose(fp); } }; int do_something(FILE *f) { fprintf(f, "This should work if you know what you're doing"); } int main(int argc, char *argv[]) { { WithOpenFile file("outfile"); } do_something(file.fp); return 0; } But Lisps will happily accept this: (defun do-something (foo) (1+ foo)) (with-open-file (file "outfile") (do-something file))
    • rbanffy 15y ago
      Fine. But now you'll have to accept both files and network sockets. What do you do?
      • anonymoushn 15y ago
        Pass the int representing the FD instead of the FILE*?
        • rbanffy 15y ago
          And then you are back to dynamic typing again, except that, when the integer you send points to something fprintf doesn't like you'll get a segfault instead of a doesNotUnderstand.
  • eropple 15y ago
    The compiler will happily compile that because C's standard library thinks it's a fantastic idea to just throw type-safety out the window. Even C libraries can protect themselves from this via strong typing instead of overloading what FILE* effectively means.