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proposal-record-tuple
ECMAScript proposal for the Record and Tuple value types. | Stage 2: it will change!
Implementations will typically use different underlying memory allocations for these strings[1], but at a language level they are considered to be the same value. If it was possible to modify one of the strings using `a[0] = "x";` it would mean `a` and `b` are not equivalent so should not be considered equal.
As explained here[2], deep immutability is not necessary for this behaviour.
In my opinion guaranteed "deep immutability" is not generally useful/meaningful (if you have a particular use case, feel free to share it). In theory it's not possible to enforce "deep immutability" because someone can always refer to something mutable, whether that's an object reference or a number indexing a mutable array.
If you really do want something that guarantees "deep immutability", this concept seems somewhat orthogonal to records/tuples, since there are existing values (eg, strings and numbers) that should be considered deeply immutable, so you'd expect to have a separate predicate[3][4] for detecting this, which would be able to effectively search a given value for object references.
In case you're interested I tried to summarise the logic behind the rejection of this behaviour[5], but it's very much a TLDR so further reading of linked issues would be required to understand the points made. Interestingly, this post is on an issue raised by the odd person that actually tried to use the feature and naturally ran into this restriction.
Sorry for this massive wall of text, but I think it's hard to capture the various trains of thought concisely.
[0] https://github.com/tc39/proposal-record-tuple/issues/387#iss...
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InfluxDB
InfluxDB high-performance time series database. Collect, organize, and act on massive volumes of high-resolution data to power real-time intelligent systems.
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And branches [1] of C are still spawning and gaining traction, because C++ is perceived as overkill.
[1]: https://github.com/c3lang/c3c
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> I do likely have a biased perspective though, as I use newer C# features every day
I think that is kind of the point, though. Many of those newer features help with simplifying code and making it less boilerplate-y. To old programmers it is a simple code fix in the IDE to move from 30 lines of variable assignments in a switch to a 5 lines switch expression and they can learn that way. People new to the language typically won't even consider going the complicated route because they learned an easier way first.
I do concede that having people with less C# experience on a team where modern C# is used, there will be constructs that are not immediately obvious. SharpLab has an “Explain” mode which would be helpful in such cases, but I haven't seen anything like that in IDEs: https://sharplab.io/#v2:C4LgpgHgDgNghgSwHYBoAmIDUAfAAgBgAJcB...
However, as a personal anecdote, we've had a number of developers who have written mostly Java 1.4 (technical reasons) before switching to C# about a year ago. They took up the newer features and syntax almost without problems. Most questions I got from them were along the lines of “Can we also use this feature?” and not “What does this do?”.
