Comment by loeg
4 years ago
> But there are also a lot of compilers out there and I would bet that all but a few has either a "this compiles c11 except for [list of unimplemented features]" caveat or non-standard extensions.
Your statement is broadly reasonable. Here's the GP:
> Shouldn’t we just come clean and admit to ourselves that there is no such thing as the C standard? There is a collection of loosely related languages that look similar and that collectively we call C, but really they’re all completely different and share almost no interoperability or common characteristics. And those standards that do exist provide almost no ability to reason about your code including things like ordering of statements.
It's just a string of incorrect statements, or at best, extreme hyperbole.
1. There is a C standard.
2. There's only one C language. Implementations differ, but not "completely," and are mostly interoperable. They all have in common the standard language, of course.
3. The C standard provides a fairly strong mental model for reasoning about code. Especially in later revisions, but even in C99. "Almost no ability to reason about" is false.
If you think C is fragmented or difficult to reason about, let me introduce you to Python (Python3, Jython, PyPy), Java (Oracle, OpenJDK, Dalvik), C# (Mono, .NET Core, .NET on Windows...), C++ (if you think implementing C99-C18 is hard, check out the stdlib required by modern versions of C++), etc.
You are right of course. I was thinking specifically about the early PIC Microchip compilers for "C" where the weird banked memory and Harvard RISC architecture made the "C" you wrote for those essentially non-portable even to other 8-bit micros. I think the Microchip marketing was very carefully trumpeting C but not claiming to follow any version of the standard though.
And, the of course, the community around PIC's where almost uniformly on board with writing in assembly anyway.
Don't know about C, but
In Java/C#/Python, you have a standard, a dominant implementation which is compliant to that standard. Few more independent/niche implementations which may not be 100% compliant. Do we have a similar implementation in C?
I think you're maybe overstating the degree of homogeneity in Java/C#/Python. E.g., CPython3 cannot run Python2 code at all, and there are a lot of platform-specific modules and behaviors in the stdlib ("import os"). I don't think Python has any real single standard to the level of detail that C does, although I may be mistaken.
For C, on approximately the same platforms, to approximately the same degree: either GCC or Clang would be the corresponding standard-compliant implementation.
CPython is looked to as the canonical Python. IronPython and PyPy are all modeled after it and aim to behave as closely to it as possible, while CPython is considered the gold standard. Comparing CPython3 and CPython2 is orthogonal to that; one is not trying to implement or emulate the other. You have similar situations with Mono C# imitating Microsoft C# and IronRuby imitating Ruby. If there is a difference, it is considered a deviation from Ruby which is the reference implementation.