5 ms·

Again, I'm not saying you should represent substrings, or strings in general for that matter, as zero terminated strings, and I'm not saying use zero terminated

Again, I'm not saying you should represent substrings, or strings in general for that matter, as zero terminated strings, and I'm not saying use zero terminated strings for anything longer than a couple bytes. No, I recommend everyone to use whatever fits the situation best. It might be a 2 byte start index and a 1 byte length fields that expresses the length as a multiple of 12 bytes. It might be rope data structure. Or it might be whatever. "String" is not a super well defined thing, and I don't understand why everybody is so super concerned about a canonical string data type. String data types are for scripting languages. 99% of my usage of string (literals) is just printf and opening files, and C does these just fine. Zero terminated strings are only a default thing for string literals that does indeed bring a little bit of simplicity and convenience (no need for a builtin string type and the associated bike shedding, and only need to pass a single pointer to functions like printf). > Meaning they become length-delineated programs, except it's done manually, tediously, and error-prone. Not sure when is the last time I found it "manually, tediously, and error-prone". There are very rare cases where I have to construct zero-terminated strings from code, or need to strlen() something because of an API. And even when these cases occur they don't bother me at all. Stuff just works for me generally and I'm moving on. I have probably 500 stupid bugs unrelated to string handling before I once forget a zero terminator, and when that one time happens I just fix it and move on. On the plus side, given that we're in C where there are no slice types, zero-terminated strings spare me to pass extra length values for format strings or filepaths. Sometimes I envision being able to use slices but I have some concerns if that would be an actual improvement. Importantly it should be about arrays and not just about strings. Strings are arrays, they aren't special. I think a good design for slices could be one whose length can never be accessed by the programmer, but which can be used for automated bounds checks. Keeping size/capacity/offset and 43 cursors into whatever buffers separate is actually correct in my view from a modularization standpoint, because "String <-> Index/Size/Offset etc." isn't a 1:1 relationship. > Whenever I review C code, the first thing I look at are the strlen/strncpy/str* sequences. It's almost always got a bug in it, an off-by-one error. You will have to look quite a bit to find strlen() or strncpy() in my code. I'm not advocating for them, and not advocating to build serious string processing on top of zero-terminated strings.

WalterBright 4y ago
D doesn't have a builtin string type. A string in D is an array of characters. All arrays are length delineated. > You will have to look quite a bit to find strlen() or strncpy() in my code. I'm not advocating for them, and not advocating to build serious string processing on top of zero-terminated strings. Rolling your own string mechanism is simply not a strength of C. The downside of rolling your own is it is incompatible with everyone else's notion of how to avoid using 0 termination.
- jstimpfle 4y ago
  I haven't even suggested to roll your own "string" type. Not more than rolling any other type of array or slice. In my programs I normally do not define a "string" type. Not a central one at least. Zero-terminated strings work just fine for the quick printf() or fopen(). Instead, I might have many string-ish types. A type to hold strings in the UI (may include layout information!), a type of string slice that points into some binary buffer, a rope string type to use in my editor, a fixed-size string as part of some message payload, a string-builder string that tries to be fast without imposing a fixed length... Again, there is little point in an "optimized" generic string type for systems programming, because... generic and optimized is a contradiction.
  - WalterBright 4y ago
    Any length delineated string you're using, and you did say you were using length delineation, suffers from the problem of not being compatible with any other C code. There's a good reason operating system API calls tend to use 0 terminated strings. If you want to do a quick debug printf() on it, well, you could use %.*s, but it's awkward and ugly (I speak from lots of experience). Otherwise, you gotta append the zero. I'm not a C newbie. I've been programming C for 40 years now. I've written 2 professional C compilers, the most recent one I finished this year. When I started D, a major priority was doing strings a better way, as C ranks among the most inconvenient string processing languages :-)
    - jstimpfle 4y ago

WalterBright 4y ago

D doesn't have a builtin string type. A string in D is an array of characters. All arrays are length delineated. > You will have to look quite a bit to find strlen() or strncpy() in my code. I'm not advocating for them, and not advocating to build serious string processing on top of zero-terminated strings. Rolling your own string mechanism is simply not a strength of C. The downside of rolling your own is it is incompatible with everyone else's notion of how to avoid using 0 termination.

jstimpfle 4y ago
I haven't even suggested to roll your own "string" type. Not more than rolling any other type of array or slice. In my programs I normally do not define a "string" type. Not a central one at least. Zero-terminated strings work just fine for the quick printf() or fopen(). Instead, I might have many string-ish types. A type to hold strings in the UI (may include layout information!), a type of string slice that points into some binary buffer, a rope string type to use in my editor, a fixed-size string as part of some message payload, a string-builder string that tries to be fast without imposing a fixed length... Again, there is little point in an "optimized" generic string type for systems programming, because... generic and optimized is a contradiction.
- WalterBright 4y ago
  Any length delineated string you're using, and you did say you were using length delineation, suffers from the problem of not being compatible with any other C code. There's a good reason operating system API calls tend to use 0 terminated strings. If you want to do a quick debug printf() on it, well, you could use %.*s, but it's awkward and ugly (I speak from lots of experience). Otherwise, you gotta append the zero. I'm not a C newbie. I've been programming C for 40 years now. I've written 2 professional C compilers, the most recent one I finished this year. When I started D, a major priority was doing strings a better way, as C ranks among the most inconvenient string processing languages :-)
  - jstimpfle 4y ago