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C# 8: Switch expressions

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Re: C# 8: Switch expressions

#101

Post by Dylan16807 »

platz wrote: post #92
Dylan16807 wrote: post #87

Earlier quoted context omitted.

Most statically-typed languages don't verify types at runtime either. As long as you enforce types at the boundaries between typed and untyped code, you should be fine. And enforcing invariants at the boundaries of your code is pretty important for all languages.

the point is that in FP languages, pattern matching uses closed ADTs, so you always know at compile time if you've covered all the cases.

Huh, you have do something with returning from a switch in typescript if you want it to make sure all cases are covered. So it's close but not quite there.

Re: C# 8: Switch expressions

#102

Post by ken »

This is perhaps the most obvious example yet of what PG described as "taking features from Lisp and gluing them to C". That's not necessarily a bad thing -- this is a great and useful feature, and one I frequently miss when using C-family languages.

I wonder, though, at what point a programming language collapses on itself, from too much syntax. I haven't used C# since the 4.x days, and I recall back then it was already on the verge of being too complex for me to fully understand. Admittedly my personal threshold of complexity is lower than most programmers', but this is a really big language. Do they plan to keep adding syntax indefinitely?

At some point, it's going to have to get eclipsed by something else. The next generation will be as effective a tool, for the kinds of things most people want to make, and not too complex for most people to understand. Perhaps part of that would consist of just using expressions for everything from the start.

Re: C# 8: Switch expressions

#103

Post by ramenmeal »

ken wrote: post #102

This is perhaps the most obvious example yet of what PG described as "taking features from Lisp and gluing them to C". That's not necessarily a bad thing -- this is a great and useful feature, and one I frequently miss when using C-family languages. I wonder, though, at what point a programming language collapses on itself, from too much syntax. I haven't used C# since the 4.x days, and I recall back then it was alre…

This is my feeling as well. I suggested that a c# lite or a rethinking of c# would be awesome. I got downvoted to oblivion though. But I do think that there's too much mental capacity used just reading c# if the code really uses all the features of it. I like go lang cause of this, but go is a bit too far on the other side of the spectrum for me.

Re: C# 8: Switch expressions

#104

Post by dmitriid »

ken wrote: post #102

This is perhaps the most obvious example yet of what PG described as "taking features from Lisp and gluing them to C". That's not necessarily a bad thing -- this is a great and useful feature, and one I frequently miss when using C-family languages. I wonder, though, at what point a programming language collapses on itself, from too much syntax. I haven't used C# since the 4.x days, and I recall back then it was alre…

> I haven't used C# since the 4.x days, and I recall back then it was already on the verge of being too complex for me to fully understand.

I can't say it's complex. If anything, the complexity has been reduced with local type inference and lambdas.

I think you wouldn't be able to tell C# from Javascript these days :)

Re: C# 8: Switch expressions

#105

Post by EpicEng »

chrismeller wrote: post #29
Someone1234 wrote: post #20

Earlier quoted context omitted.

string interpolation isn't simply a wrapper around String.Format(); it also offers compile time checking which solved a real limitation of String.Format() while offering better performance than concatenation. For example: var h = "Hello "; var w = "world"; var output = String.Format("{1} {2}", h, w); output = $"{h} {w}"; Would compile fine but throw on the String.Format() line due to the typo.

I wasn’t necessarily saying it doesn’t offer any benefit, more that it’s not really a benefit that seems to benefit a lot of people. Between code intelligence tools and actually running the code you write (not even in an actual QA process, but simply executing each line) that just doesn’t seem like a big deal to me. There are also instances where, such as with Console.Write you are now formatting a string in order to…

>a fairly obvious decrease in clarity

In what's ways specifically? Using String.Format you have to keep your indices correct and 'compiling' the string in your head requires jumping back and forth between the format string and the args.

Interpolation wins on every account as far as I'm concerned.

Re: C# 8: Switch expressions

#106

Post by EpicEng »

chrismeller wrote: post #32
scarface74 wrote: post #17

Earlier quoted context omitted.

String interpolation is more intuitive than trying to match a placeholder in the string with a list outside of the string.

I suppose that depends upon where you’re coming from. Many, many languages have an sprintf-style construct of one form or another, so I think it’s actually much more familiar to most people to have a placeholder with an optional formatter. To each their own, though.

I have a hard time believing any programmer with more than a couple of months experience would have a moment of difficult figuring out what an interpolated string is doing.

Re: C# 8: Switch expressions

#107

Post by EpicEng »

chrismeller wrote: post #35
martindevans wrote: post #23

Earlier quoted context omitted.

String.Format("Is {0} to read {2} {1} of the {3} out of place", "harder", "half", "because", "string is").

Ironically that’s actually also one of the key advantages of it. If you have a long string with many placeholders in it and need to add a new one in the middle... you just add it and don’t have to figure out where in the list of params to insert the new arg.

Yes, God forbid the variable appear more than once.

Re: C# 8: Switch expressions

#108

Post by doodpants »

jermaustin1 wrote: post #11

I'm not sure what this accomplishes over a normal ugly switch.

The new switch expression is to the old switch statement what the ?: operator is to the if/else statement.

Sometimes you want to provide one of two different values based on a condition. If you use if/else, then each statement body has to contain either an assignment (if the value is to be used later in the same function), or a return (if the value is to be immediately returned from the enclosing function). It is often more clear and concise to use a ?: expression at the site where the value is to be used.

Now consider the case where you need to choose among three or more different values. You can use chained if/else statements, which have the same drawback of needing to contain either assignments or returns. Or you can use chained ?: expressions, but there's really no good way to format this in a way that remains clean and easy to understand.

The new switch expression provides a cleaner alternative to chained ?: expressions.

Re: C# 8: Switch expressions

#109

Post by yarg »

ramenmeal wrote: post #103
ken wrote: post #102

This is perhaps the most obvious example yet of what PG described as "taking features from Lisp and gluing them to C". That's not necessarily a bad thing -- this is a great and useful feature, and one I frequently miss when using C-family languages. I wonder, though, at what point a programming language collapses on itself, from too much syntax. I haven't used C# since the 4.x days, and I recall back then it was alre…

This is my feeling as well. I suggested that a c# lite or a rethinking of c# would be awesome. I got downvoted to oblivion though. But I do think that there's too much mental capacity used just reading c# if the code really uses all the features of it. I like go lang cause of this, but go is a bit too far on the other side of the spectrum for me.

Having something more akin to typescript's strict compilation might be more reasonable.

You'd mark out older syntaxes/APIs as restricted or deprecated and compilations would yield warnings or errors (when those features were used) depending on the compiler level.

This would allow new projects to be developed using only the newer (standard) syntax, while allowing a transitional vector for older projects.

Re: C# 8: Switch expressions

#110

Post by xkapastel »

ramenmeal wrote: post #103
ken wrote: post #102

This is perhaps the most obvious example yet of what PG described as "taking features from Lisp and gluing them to C". That's not necessarily a bad thing -- this is a great and useful feature, and one I frequently miss when using C-family languages. I wonder, though, at what point a programming language collapses on itself, from too much syntax. I haven't used C# since the 4.x days, and I recall back then it was alre…

This is my feeling as well. I suggested that a c# lite or a rethinking of c# would be awesome. I got downvoted to oblivion though. But I do think that there's too much mental capacity used just reading c# if the code really uses all the features of it. I like go lang cause of this, but go is a bit too far on the other side of the spectrum for me.

> I suggested that a c# lite or a rethinking of c# would be awesome.

"a rethinking of C#" is a good description of F#.

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