alt Hacker NewsI'm not sure why people seem to be under the impression that writing a compiler means that the language the compiler is implemented in should have "low level" features. A compiler is just a text -> text translation tool if you can leverage other tools such as an assembler and never needs to access machine level instructions. E.g., Pascal compilers have traditionally been written in Pascal, hardly a language which conjures up a "low level" image. Even when an assembler isn't available, all your implementation language needs to support, in terms of "low level" features, is writing of bytes to a file.
But manipulating instruction and file formats and such can be tedious if your language doesn't have the right capabilities but it's not impossible.
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> I'm not sure why people seem to be under the impression that writing a compiler means that the language the compiler is implemented in should have "low level" features.
Performance.
You definitely can write a compiler in a high-level language and given the choice I certainly prefer to on my hobby projects. Having a garbage collector makes so many compiler algorithms and data structures easier.
But I also accept that that choice means there's an upper limit to how fast my compiler will. If you're writing a compiler that will be used to (at least aspirationally) compile huge programs, then performance really matters. Users hate waiting on the compiler.
When you want to squeeze every ounce of speed you can get out of the hardware, a low-level language that gives you explicit control over things like memory layout matters a lot.
It's because a compiler is supposed to be high-level to low-level; you already have a lower-level language to write in it, and not a higher-level one. Writing a C compiler in a higher-level language than C is going backwards.
E.g., Pascal compilers have traditionally been written in Pascal, hardly a language which conjures up a "low level" image.
How could the first Pascal compiler be compiled if it was written in Pascal, but a Pascal compiler didn't yet exist?
This comment started out strong, but then:
> Pascal compilers have traditionally been written in Pascal, hardly a language which conjures up a "low level" image.
It may be the case that it doesn't conjure up such an image, but Pascal is approximately on the same rung as Zig or D—lower level than Go, higher level than assembly. If folks have a different impression, the problem is just that: their impression.