Hi all, I just wanted to know if it is possible to unpack named tuples in the following context. I know that Parameters.jl addresses some related issues, but I have not been able to figure out if it can handle the following case. Define a named tuple using @with_kw: ParamsNamedTuple = @with_kw ( …

you need to know ahead of time the number of values if you gonna assign them. but extracting the values of a NamedTuple can be done via the function values tup = (a=3,b=5) #example named tuple tup_values = values(tup) # (3,5) a,b = values(tup) #a = 3, b = 5, two variables defined this approach req…

The @eval solution also only works at global scope: julia> function foo() tup = (a = 1, b=2) @unpack_namedtuple tup a = a + 1 end foo (generic function with 1 method) julia> foo() ERROR: UndefVarError: a not defined Stacktrace: [1] foo() at ./REPL[6]:4 [2] top-l…

Hi @rdeits , thanks for your detailed answer! [image] rdeits: But what would the generated code be for the hypothetical @unpack params ? That is exactly the question. However, this was just syntax, it was not the proposed solution. I know that the input to the macro is just the symbol :params.…

[image] rvignolo: create a macro @unpack_ParamsNamedTuple on the fly. If you have a specific NamedTuple type that you use an alias for, you might as well just define struct, they are much nicer for dispatch etc.

[image] rvignolo: I though that the macro may return something like @longemen3000 suggested. That’s totally reasonable to hope for, but it won’t work precisely because the suggested code, even if written out by hand, still doesn’t work (it creates global variables, not local ones, because tha…

[image] rdeits: That’s totally reasonable to hope for, but it won’t work precisely because the suggested code, even if written out by hand, still doesn’t work (it creates global variables, not local ones, because that is inherently how @eval always works). This is correct! [image] rdeits: …

Hi @Tamas_Papp , thanks for your reply. You may find useful this discussion in order to see why I would like to have named tuples instead of structs.

I am still not sure if I understand why you can’t use structs, even after reading that issue, but as suggested there you can just have the user pass functions. The fundamental difficulty with a macro is that macros operate on syntax, while (in general) the fields depend on the type of a value. Ther…

I started thinking about this recently after seeing this thread . I mostly agree with @Tamas_Papp that a struct is likely the best solution, however I think these sorts of code transformations are interesting to think about. Basically, what would be needed to do this is a macro that knows about type…

btw [image] Destructuring syntax in julia 1.7 Internals & Design 1.7 introduced new language feature: (; a, b) = x can now be used to destructure properties a and b of x . This syntax is equivalent to a = getproperty(x, :a); b = getproperty(x, :b) From a reader perspecti…

Unpack named tuples (does anyone know how to do it?)

General Usage

jling June 18, 2022, 5:38pm 14

btw

Topic		Replies	Views
Named tuples - construction, unpacking General Usage question , namedtuple	2	12338	December 2, 2020
Selective deconstruction of NamedTuples to local variables? General Usage	2	380	August 15, 2019
Unpacking a named tuple using field names and slurping? General Usage	15	802	June 11, 2023
Function arguments General Usage tuple , function , namedtuple , named-tuple	37	1875	December 20, 2024
Destructuring NamedTuples with Regular Expressions General Usage destructuring	6	400	October 10, 2022

Unpack named tuples (does anyone know how to do it?)

Related topics