Oops, I Wrote a C++ Compiler
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Oops, I Wrote a C++ Compiler
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Re: Oops, I Wrote a C++ Compiler
#2The process of creating the parser went very smoothly thanks to this. The real work involves creating C# syntax classes that mirror the grammar. These classes form the Abstract Syntax Tree (AST) of the compiler.
To address this problem, I use Zephyr ASDL to describe the abstract syntax of a language (which CPython also uses!)
It's a little DSL that lets you write an ML-style algebraic data type, and generates a bunch of code for you. In CPython, you go from ~100 lines ASDL schema to ~10,000 lines of C! It underlies the 'ast' module in the stdlib.
Why is Zephyr ASDL? http://www.oilshell.org/blog/2016/12/11.html
It eliminates the need for a lot of boilerplate he pointed out:
https://github.com/praeclarum/CLanguage/tree/master/CLanguag...
Re: Oops, I Wrote a C++ Compiler
#3Please don't call it C++ if it doesn't even support constructors and destructors.
People will be trying to port their existing code, and will be unpleasantly surprised.
> But the truth is, I’m just going to keep listening to users and improving the parts I can. I am not trying to recreate GCC or LLVM.
Why not use GCC or LLVM as part of your project? That seems like a better investment of your time.
Re: Oops, I Wrote a C++ Compiler
#4More like a “C++ [1] compiler”.
[1] restrictions may apply
Re: Oops, I Wrote a C++ Compiler
#5Please don't call it C++ if it doesn't even support constructors and destructors. People will be trying to port their existing code, and will be unpleasantly surprised. > But the truth is, I’m just going to keep listening to users and improving the parts I can. I am not trying to recreate GCC or LLVM. Why not use GCC or LLVM as part of your project? That seems like a better investment of your time.
> Please don't call it C++ if it doesn't even support constructors and destructors.
At least they recognize this is missing, and call it out.
> Why not use GCC or LLVM as part of your project? That seems like a better investment of your time.
Learning opportunity? Maybe they're trying to solve a problem? Or do you think the LLVM folks should have just used GCC instead of wasting their time on LLVM?
Re: Oops, I Wrote a C++ Compiler
#6Please don't call it C++ if it doesn't even support constructors and destructors. People will be trying to port their existing code, and will be unpleasantly surprised. > But the truth is, I’m just going to keep listening to users and improving the parts I can. I am not trying to recreate GCC or LLVM. Why not use GCC or LLVM as part of your project? That seems like a better investment of your time.
It is very well explained? GCC and Clang would be nightmares to integrate into an app that runs on many platforms including iOS, and even once you did, you'd still need to implement an interpreter, because you're not allowed to JIT on the app store. Compiling a toolchain for a desktop platform is easy. Cross compiling a toolchain is moderately easy. But embedding a toolchain into an iOS app, where you have to get it and all of its dependencies compiling for iOS, definitely seems like a massive challenge.
Re: Oops, I Wrote a C++ Compiler
#7Very cool
Re: Oops, I Wrote a C++ Compiler
#8This post reminded me of myself in 2012. Where did all that energy go?
Re: Oops, I Wrote a C++ Compiler
#9Please don't call it C++ if it doesn't even support constructors and destructors. People will be trying to port their existing code, and will be unpleasantly surprised. > But the truth is, I’m just going to keep listening to users and improving the parts I can. I am not trying to recreate GCC or LLVM. Why not use GCC or LLVM as part of your project? That seems like a better investment of your time.
> Why not use GCC or LLVM as part of your project?
That's not how the world gets compiler people.
Someone had to write GCC and LLVM, and someone will have to write whatever comes next. Languages and tooling only advance because there are those who choose to take the hard road instead of "just using that thing that someone else made".
Re: Oops, I Wrote a C++ Compiler
#10Please don't call it C++ if it doesn't even support constructors and destructors. People will be trying to port their existing code, and will be unpleasantly surprised. > But the truth is, I’m just going to keep listening to users and improving the parts I can. I am not trying to recreate GCC or LLVM. Why not use GCC or LLVM as part of your project? That seems like a better investment of your time.
Indeed, for a moment I thought that someone had actually figured out how to condense the C++ standard enough to write a full compiler for it, like we've seen many times here on HN with C/C subset compilers.
It's more accurately a "C superset" compiler, or perhaps "C+".