Comment by jph | Hacker News Reader

Comment by jph | Hacker News Reader

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I like the emphasis on simplicity. I like the functions, the namespaces, the customizability of allocators, and more. Much respect to the author for creating Muon and sharing it.

What sets Muon apart from all other languages that I've personally tried is that Muon seems to have chosen a unique indentation approach. First, there is a double-syntax for blocks, because Muon requires block indents with significant whitespace (akin to Python) and simultaneously requires block open/close braces (akin to C). Second there is a free choice of tabs or spaces (but not both) and simultaneously a meta-markup line that a developer can put at the top of a file that enables mixing tabs and spaces.

IMHO these kind of whitespace choices seem small at first, yet eventually make open source development more difficult when teams make different choices, and when teaching examples make different choices. I'm a big proponent of `rustfmt`, `gofmt`, and similar tooling that makes it easy to align diverse teams from many groups.

That's a fair point. It's the reason that I've marked significant whitespace as "experimental" in the documentation. Since the language is in an early stage, I think it's OK to try some slightly more experimental constructs for now. The feature does provide some nice benefits in terms of parsing robustness, which is really noticeable especially when working with live error feedback (i.e. language server, coming soon).

But rest assured, this is very much on my radar! If it turns out to be too much of a pain, I'll remove it (or make it opt in). Fortunately, because of the redundant braces the transition would be seamless: we can just drop the whitespace requirement.

I think it's a great idea. I think you could perhaps reword it to make things a bit less weird sounding though: blocks are created using curly brackets, but correct indentation is enforced by the compiler. Indenting weirdly (e.g. mixing spaces/tabs) will cause a compile error.

Also I can't see how it would affect code sharing at all. I assume it is per-file, so adding entire files won't matter, and if you have a project that wants to steal a bit of code from another in one file, surely you want to convert their indentation to yours - which would be trivial to do given that you enforce correct indentation.

I think it is a good idea. If you ban tabs you'll piss off the sane 50% of programmers, and if you ban spaces you'll piss off the other 50%. Allowing either but with no mixing makes sense.

The only exception I can think of is that some people like to do tabs for indentation and spaces for alignment. Dunno if you could support that easily...

With regards to your last point, that would be fine. The compiler doesn't care about spaces vs tabs after the first non-whitespace character of a line, as that's not relevant to how the code is parsed.

I actually think that this is pretty close to the sweet spot. You make line breaks significant, but not the indentation level. The indentation will be inferred automatically from the braces. That way you can paste code that has the wrong indentation, hit save, and as long as the braces are balanced, the indentation will get fixed automatically by an auto-formatter.

I would be very interested to know how happy Python programmers are with the indentation level being significant. Did Guido ever say anything about it?

I worked almost exclusively in python for about five years and loved significant whitespace. It was one of the things I missed most when working in other languages. Now I work primarily in Haskell which has significant whitespace with optional braces and I still love significant whitespace and never use the brace style.

In practice I found the copy/paste problem exceedingly rare to the point that it has been completely a non-issue in both languages.

Look at how much of this discussion is on formatting, and it's the top threads.

Make a "mufmt" with zero options and let everyone focus on important things.

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