Empty lists do not evaluate to true with empty?

[bugabinga]

Describe the bug

According to the book an empty table piped to empty? should return true.
However it seems to print an empty line instead.

How to reproduce

let colors = []
$colors | empty?

or simply

[] | empty?

Expected behavior

[] | empty? should print true.

Screenshots

No response

Configuration

version | pivot | to md

Column0	Column1
version	0.35.0
build_os	windows-x86_64
rust_version	rustc 1.54.0 (a178d0322 2021-07-26)
rust_channel	stable-x86_64-pc-windows-msvc (default)
cargo_version	cargo 1.54.0 (5ae8d74b3 2021-06-22)
pkg_version	0.35.0
build_time	2021-08-04 10:11:37
build_rust_channel	release
features	clipboard-cli, ctrlc, dataframe, default, rustyline, term, trash, uuid, which, zip
installed_plugins	binaryview, chart bar, chart line, fetch, from bson, from sqlite, inc, match, post, ps, query json, s3, selector, start, sys, textview, to bson, to sqlite, tree, xpath

Additional context

Other datatypes work as expected with empty?.

∽
  1 | empty?
false

∽
  "" | empty?
true

∽
  $true | empty?
false

∽
  $false | empty?
false

∽
  0 | empty?
false

∽
  () | empty?
true

∽
  $nothing | empty?
true

∽
  0.0 | empty?
false

∽
  0sec | empty?
false

∽
  0..0 | empty?
false

∽
  0b | empty?
false

∽
  [[];[]] | empty?
true

∽
  {} | empty?
true

Notice the table type in particular .
An empty table works: [[];[]].
But an empty list seemingly not: [].

[jafriyie1]

@fdncred Is anyone working on this? I'd like to give this a shot if no one is.

[fdncred]

Go for it @jafriyie1

[fdncred]

Similar issue #3929

[fdncred]

@jafriyie1 how's it going on this issue? We've had requests similar to yours here recently.

[jafriyie1]

@fdncred I stepped away a while from this as I got busy with other things. my apologies. I made a test for the corrected behavior and I am noticing that the issue comes from here empty_code. When I was testing around with this I saw that [] | empty? returns "" instead of true or false.

In addition to this, when we pass in ([] | empty?) | empty? we get the expected boolean. This makes me think that the parser for some reason treats an empty list [] differently than other values. Because of this, I'm wondering how I should go about fixing this. Should we just make an explicit match on []? Or is there a more elegant approach to this?

[fdncred]

I'm not sure @jafriyie1. @jntrnr any thoughts on this?