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How I wrote a self-hosting C compiler in 40 days

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429 points rui314 | 1 comments | 14 Dec 15 14:07 UTC | HN request time: 0s | source
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tomcam ◴[14 Dec 15 14:57 UTC] No.10731290[source]▶
I was a little surprised that the author was able to manage both C11 and the preprocessor in that time. The preprocessor is hard. But there was existing code from a previous version of it, which makes sense. Still, a fantastic achievement! Congrats to the author!
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eliben ◴[14 Dec 15 17:57 UTC] No.10732574[source]▶
Out of curiosity - why do you consider cpp particularly hard? It's easier than the compiler, actually :)
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tomcam ◴[14 Dec 15 23:08 UTC] No.10734688[source]▶
Well... easier than the compiler but very hard to do the last 20% (I never had the time; hobby project) because docs are so hard to find. Or at least were--maybe that's changed.
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eliben ◴[15 Dec 15 00:47 UTC] No.10735178[source]▶
What docs? It's all in the standard
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rui314 ◴[15 Dec 15 01:51 UTC] No.10735443[source]▶
The standard says too little about the preprocessor. I don't think you can implement a preprocessor that can read system header files only with the standard.
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1. eliben ◴[15 Dec 15 13:53 UTC] No.10737730[source]▶
System header files usually employ platform-specific extensions not only on the preprocessor side, but in preprocessed code as well AFAIK. That is, the compiler has to support them too.

My comment was not to say that coding cpp is easy - just that it's not a particularly hard task compared to the compiler itself.