//: Everything this project/binary supports. //: This should give you a sense for what to look forward to in later layers. :(before "End Commandline Parsing") if (argc <= 1 || is_equal(argv[1], "--help")) { // this is the functionality later layers will provide // currently no automated tests for commandline arg parsing cerr << "To load files and run 'main':\n" << " mu file1.mu file2.mu ...\n" << "To run all tests:\n" << " mu test\n" << "To load files and then run all tests:\n" << " mu test file1.mu file2.mu ...\n" << "To load all files with a numeric prefix in a directory:\n" << " mu directory1\n" << "You can test directories just like files.\n" << "To pass ingredients to a mu program, provide them after '--':\n" << " mu file_or_dir1 file_or_dir2 ... -- ingredient1 ingredient2 ...\n" ; return 0; } //:: Helper function used by the above fragment of code (and later layers too, //:: who knows?). //: The :(code) directive appends function definitions to the end of the //: project. Regardless of where functions are defined, we can call them //: anywhere we like as long as we format the function header in a specific //: way: put it all on a single line without indent, end the line with ') {' //: and no trailing whitespace. As long as functions uniformly start this //: way, our makefile contains a little command to automatically generate //: declarations for them. :(code) bool is_equal(char* s, const char* lit) { return strncmp(s, lit, strlen(lit)) == 0; } //: I'll throw some style conventions here for want of a better place for them. //: As a rule I hate style guides. Do what you want, that's my motto. But since //: we're dealing with C/C++, the one big thing we want to avoid is undefined //: behavior. If a compiler ever encounters undefined behavior it can make //: your program do anything it wants. //: //: For reference, my checklist of undefined behaviors to watch out for: //: out-of-bounds access //: uninitialized variables //: use after free //: dereferencing invalid pointers: null, a new of size 0, others //: //: casting a large number to a type too small to hold it //: //: integer overflow //: division by zero and other undefined expressions //: left-shift by negative count //: shifting values by more than or equal to the number of bits they contain //: bitwise operations on signed numbers //: //: Converting pointers to types of different alignment requirements //: T* -> void* -> T*: defined //: T* -> U* -> T*: defined if non-function pointers and alignment requirements are same //: function pointers may be cast to other function pointers //: //: Casting a numeric value into a value that can't be represented by the target type (either directly or via static_cast) //: //: To guard against these, some conventions: //: //: 0. Initialize all primitive variables in functions and constructors. //: //: 1. Minimize use of pointers and pointer arithmetic. Avoid 'new' and //: 'delete' as far as possible. Rely on STL to perform memory management to //: avoid use-after-free issues (and memory leaks). //: //: 2. Avoid naked arrays to avoid out-of-bounds access. Never use operator[] //: except with map. Use at() with STL vectors and so on. //: //: 3. Valgrind all the things. //: //: 4. Avoid unsigned numbers. Not strictly an undefined-behavior issue, but //: the extra range doesn't matter, and it's one less confusing category of //: interaction gotchas to worry about. //: //: Corollary: don't use the size() method on containers, since it returns an //: unsigned and that'll cause warnings about mixing signed and unsigned, //: yadda-yadda. Instead use this macro below to perform an unsafe cast to //: signed. We'll just give up immediately if a container's ever too large. :(before "End Includes") #define SIZE(X) (assert((X).size() < (1LL<<(sizeof(long long int)*8-2))), static_cast((X).size())) //: //: 5. Integer overflow is still impossible to guard against. Maybe after //: reading http://www.cs.utah.edu/~regehr/papers/overflow12.pdf :(before "End Includes") #include #include using std::istream; using std::ostream; using std::iostream; using std::cin; using std::cout; using std::cerr; #includ