Possibility of output object with named values?

[xsvato01]

Hi, I was wondering if it is possible in Nextflow to ouput named object from processes. For example:

process Foo {
	output:
	tuple path("file.txt"), ['word': env(SAY), 'something_else': val(8)]

	script:
	"""
        touch file.txt
	SAY=\$(echo whatever)
 	"""
}

This will not work, but something similar can be achieved with

process Foo {
	output:
	tuple path("file.txt"), env(SAY),  val(8)

	script:
	"""
        touch file.txt
	SAY=\$(echo whatever)
 	"""
}

workflow {
	Foo()
	.map{ it -> [ it[0], [word: it[1], something_else: it[2] ] }
	.view()
}

Perhaps there is any more elegant way without needing to map over the individual outputs...?

[bentsherman]

For now your example is the best you can do. Named outputs (record types) are on the roadmap, but there are a few moving pieces involved so I'm not yet sure when it will be ready

[xsvato01]

Lovely, thanks for the heads-up!

[tobsecret]

This is very exciting! Will this also come with support for named arguments?

Have been looking over a bunch of nf-core pipelines recently.
I cannot shake the feeling that a lack of support for named arguments and named outputs for processes is what leads to patterns that I find hard to read.

some_earlier_process_out_ch.map{
it -> [it[0], it[2], it[3]] 
}.set{
some_ch
}
SOME_PROCESS(some_ch)

I now need to go back to that earlier process and read what its outputs were and in which order they occur.
Maybe I'm also not making enough use of DSL2 functionality and this is already sth that can be done? Would love to hear advice!

[bentsherman]

You can already do a sort of tuple de-structuring with closures:

some_earlier_process_out_ch
  .map { a, b, c, d -> [a, c, d] }
  .set { some_ch }
SOME_PROCESS(some_ch)

[tobsecret]

Ah nice, that's helpful! Thank you so much for the quick followup!
I still think we would like being able to pass values between processes entirely by name but this is def helpful in the interims - so much more readable.

[tobsecret]

So the way I am thinking about it, it would look sth like:

SOME_PROCESS(a = some_earlier_process_out_ch.a, c = some_earlier_process_out_ch.c, d = some_earlier_process_out_ch.d)

Or even simpler, if the accepted arg names are in the hashmap that is passed:

SOME_PROCESS(some_earlier_process_out_ch)

Similar to python's some_func(**kwargs) pattern.