alt Hacker NewsPascal strings might be the only string design worse than C strings. C Strings at least let you take a zero copy substring of the tail. Pascal strings require a copy for any substring! Strings should be two machine words - length + pointer (aka what is commonly called a string view). This is no different than any other array view. Strings are not a special case.
Replies
Yeah, I too feel that storing the array's length glued to the array's data is not that good of an idea, it should be stored next to the pointer to the array aka in the array view. But the thrall of having to pass around only a single pointer is quite a strong one.
The "zero copy substring" in C is in general not a valid C string since it is not guaranteed to be zero-terminated. For both languages one could define a string view as a struct with a pointer plus size information. So, I do not see why Pascal is worse in this regard than C.
C strings also allow you to do a 0 copy split by replacing all instances of the delimeter with null (although you need to keep track of the end-of-list seperatly).
x86 had 6 general-purpose working registers total. Using length + pointers would have caused a lot of extra spills.
> C Strings at least let you take a zero copy substring of the tail
This is a special-case optimisation that I'm happy to lose in favour of the massive performance and security benefits otherwise.
Isn't length + pointer... Basically a Pascal string? Unless I am mistaken.
I think what was unsaid in your second point is that we really need to type-differentiate constant strings, dynamic strings, and string 'views', which Rust does in-language, and C++ does with the standard library. I prefer Rust's approach.