Issue #8909 has been updated by matz (Yukihiro Matsumoto).


"string" is a literal, but {a: 1} and [1, 2] are expressions.
Thus we have to define {}f and []f to be shallow freezing or deep freezing.
If it's deep freezing, freezing objects (not literals) could be troublesome.

We have to define a concrete behavior first to discuss.

Matz.

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Feature #8909: Expand "f" frozen suffix to literal arrays and hashes
https://bugs.ruby-lang.org/issues/8909#change-41808

Author: headius (Charles Nutter)
Status: Open
Priority: Normal
Assignee: 
Category: 
Target version: 


The "f" suffix to declare a frozen string was recently accepted into 2.1, and I think it's a spectacular addition. I would very much like to see it work for literal arrays and hashes too:

[1, 2, 3, 4, 5]f

{foo: 1, bar: 2, baz: 3}f

There are many, many cases where this could reduce allocation (frozen array with literal elements would only need to be allocated once) and improve thread-safety (explicitly create frozen arrays and hashes when creating structures that might be used across threads).

Is there any reason why we could not do this? I believe both of the above syntaxes would be invalid today, as was the case with the String "f" suffix, and hopefully that means the work to add this syntax would be similar.


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