Table and list helper commands (#967)

From https://github.com/nushell/nushell/issues/13887, this adds:

```nu
into list
select ranges
select column-ranges
reject ranges
reject column-ranges
row-indices
col-indices
```

Note that these replace the former `get-row` and `get-col` commands that
were in the library. They have the same functionality and can accept any
combination of:

* One or more row or column indices
* One or more row or column ranges

stdlib-candidate/std-rfc/conversions/into.nu

@@ -0,0 +1,18 @@
+# Convert a Nushell value to a list
+# 
+# Primary useful for range-to-list,
+# but other types are accepted as well.
+# 
+# Example:
+#
+# 1..10 | into list
+export def "into list" []: any -> list {
+  let input = $in
+  let type = ($input | describe --detailed | get type)
+  match $type {
+    range => {$input | each {||}}
+    list => $input
+    table => $input
+    _ => [ $input ]
+  }
+}

stdlib-candidate/std-rfc/conversions/mod.nu

@@ -0,0 +1 @@
+export use ./into.nu *

stdlib-candidate/std-rfc/get-column.nu

@@ -1,23 +0,0 @@
-# Documentation for get-col
-# Written on 2021-03-28 06:58:50 by andras_io on discord
-# Written for the new Nushell version on 03/31/2022 10:10 PM by denkspuren on discord
-def get-col [
-     col_index:int # A 0 indexed col_index
-    ] {
-
-    # meant to be used like `ls | get-col 1`
-    let input = $in
-    let name = ($input | columns | select $col_index | get 0)
-    $input | select $name
-}
-
-# Documentation for get-col2
-# Written on 2021-03-28 07:00:24 by johng on discord
-# Written for the new Nushell version on 03/31/2022 10:10 PM by denkspuren on discord
-def get-column [
-     col_index:int # A 0 indexed col_index
-    ] {
-
-    # meant to be used like `ls | get-column 1`
-    $in | transpose | select $col_index | transpose | select column1 | headers
-}

stdlib-candidate/std-rfc/get-row.nu

@@ -1,6 +0,0 @@
-# This is a wrapper to get a row
-def get-row [
-    row_num:int # A 0 indexed row
-    ] {
-    $in | get $row_num | table --index $row_num
-}

stdlib-candidate/std-rfc/mod.nu

@@ -1,9 +1,12 @@
-# modules
+# Modules
 export module record/
 export module str/
 export module math/
-# commands
+
+# Commands
 export use bulk-rename.nu *
 export use set-env.nu *
 export use bench.nu
 export use script-parsing.nu [ parse-arg ]
+export use conversions *
+export use tables *

stdlib-candidate/std-rfc/tables/col-indices.nu

@@ -0,0 +1,15 @@
+use ../conversions/into.nu *
+use ./select-ranges.nu *
+
+export def main [ ...ranges ] {
+  let indices = (
+    $ranges
+    | reduce -f [] {|range,indices|
+      $indices ++ ($range | into list)
+    }
+  )
+
+  $in | columns
+  | select ranges $indices 
+  | get item
+}

stdlib-candidate/std-rfc/tables/mod.nu

@@ -0,0 +1,6 @@
+export use ./select-ranges.nu *
+export use ./reject-ranges.nu *
+export use ./select-column-ranges.nu *
+export use ./reject-column-ranges.nu *
+export use ./row-indices.nu *
+export use ./col-indices.nu *

stdlib-candidate/std-rfc/tables/reject-column-ranges.nu

@@ -0,0 +1,13 @@
+use ./col-indices.nu *
+
+# Relect a range of columns by their indices
+#
+# Example:
+# 
+# ls | reject column-ranges 0 4 5 | first 3
+export def "reject column-ranges" [
+    ...ranges
+] {
+    let column_selector = ($in | col-indices ...$ranges)
+    $in | reject ...$column_selector
+}

stdlib-candidate/std-rfc/tables/reject-ranges.nu

@@ -0,0 +1,14 @@
+use ./row-indices.nu *
+
+# Rejects one or more rows while keeping
+# the original indices.
+#
+# Example - Rejects the first, fifth, and
+# sixth rows from the table:
+#
+# ls / | reject ranges 0 4..5
+export def "reject ranges" [ ...ranges ] {
+  enumerate
+  | flatten
+  | reject ...(row-indices ...$ranges)
+}

stdlib-candidate/std-rfc/tables/row-indices.nu

@@ -0,0 +1,25 @@
+use ../conversions/into.nu *
+
+# Return a list of indices
+# for the provided ranges or indices.
+# Primarily used as a helper for
+# "select ranges" et. al.
+#
+# Example:
+#
+# row-indices 0 2..5 7..8
+# # => ╭───┬───╮
+# # => │ 0 │ 0 │
+# # => │ 1 │ 2 │
+# # => │ 2 │ 3 │
+# # => │ 3 │ 4 │
+# # => │ 4 │ 5 │
+# # => │ 5 │ 7 │
+# # => │ 6 │ 8 │
+# # => ╰───┴───╯
+export def main [ ...ranges ] {
+  $ranges
+  | reduce -f [] {|range,indices|
+    $indices ++ ($range | into list)
+  }
+}

stdlib-candidate/std-rfc/tables/select-column-ranges.nu

@@ -0,0 +1,20 @@
+use ./col-indices.nu *
+
+# Select a range of columns by their indices
+#
+# Example:
+# 
+# ls -l | select column-ranges 0 10..12 | first 3
+# # => ╭───┬────────────────────┬──────────────┬─────────────┬──────────────╮
+# # => │ # │        name        │   created    │  accessed   │   modified   │
+# # => ├───┼────────────────────┼──────────────┼─────────────┼──────────────┤
+# # => │ 0 │ CITATION.cff       │ 3 months ago │ 4 hours ago │ 3 months ago │
+# # => │ 1 │ CODE_OF_CONDUCT.md │ 7 months ago │ 4 hours ago │ 7 months ago │
+# # => │ 2 │ CONTRIBUTING.md    │ 3 months ago │ 4 hours ago │ 3 months ago │
+# # => ╰───┴────────────────────┴──────────────┴─────────────┴──────────────╯
+export def "select column-ranges" [
+    ...ranges
+] {
+    let column_selector = ($in | col-indices ...$ranges)
+    $in | select ...$column_selector
+}

stdlib-candidate/std-rfc/tables/select-ranges.nu

@@ -0,0 +1,26 @@
+use ./row-indices.nu *
+
+# Selects one or more rows while keeping
+# the original indices.
+#
+# Example - Selects the first, fifth, and
+# sixth rows from the table:
+#
+# ls / | select ranges 0 4..5
+#
+# Example - Select the 5th row:
+#
+# ls / | select 5
+#
+# Example - Select the 4th row.
+# Note that the difference beteen this
+# and `select 3` is that the index (#)
+# column shows the *original* (pre-select)
+# position in the table.
+#
+# ls | select ranges 3
+export def "select ranges" [ ...ranges ] {
+  enumerate
+  | flatten
+  | select ...(row-indices ...$ranges)
+}

stdlib-candidate/tests/bulk-rename.nu

@@ -40,7 +40,10 @@ export def 'test --verbose' [] {
         _test.nu
     ]
     let renamed = test $fixture {
-        ls $in | bulk-rename --verbose --no-execute { '_' + $in }
+        # Note: Currently failing due to Nushell core #13267
+        # Remove the 'sort' once it is fixed
+        # ls $in | bulk-rename --verbose --no-execute { '_' + $in }
+        ls $in | bulk-rename --verbose --no-execute { '_' + $in } | sort
     }
     assert equal ($renamed.new | each { path basename }) $expects
 }

stdlib-candidate/tests/conversions.nu

@@ -0,0 +1,43 @@
+use std assert
+use ../std-rfc/conversions *
+
+export def "test range-into-list" [] {
+  assert equal (
+    1..10 | into list
+  ) (
+    [ 1 2 3 4 5 6 7 8 9 10 ]
+  )
+}
+
+export def "test string-into-list" [] {
+  assert equal (
+    "foo" | into list
+  ) (
+    [ foo ]
+  )
+}
+
+export def "test range-stride-into-list" [] {
+  assert equal (
+    0..2..10 | into list
+  ) (
+    [ 0 2 4 6 8 10 ]
+  )
+}
+
+export def "test null-into-list" [] {
+  assert equal (
+    null | into list | get 0 | describe
+  ) (
+    "nothing"
+  )
+}
+
+export def "test list-into-list" [] {
+  assert equal (
+    [ foo bar baz ] | into list
+  ) (
+    [ foo bar baz ]
+  )
+
+}

stdlib-candidate/tests/mod.nu

@@ -5,3 +5,5 @@ export module math.nu
 export module bench.nu
 export module script-parsing.nu
 export module str_dedent.nu
+export module conversions.nu
+export module tables.nu

stdlib-candidate/tests/tables.nu

@@ -0,0 +1,168 @@
+use std assert
+use ../std-rfc/tables *
+
+const test_table = [
+  [ col-a     col-b     col-c     col-d     col-e     col-f ];
+  [  'a0'      'b0'      'c0'      'd0'      'e0'      'f0' ]
+  [  'a1'      'b1'      'c1'      'd1'      'e1'      'f1' ]
+  [  'a2'      'b2'      'c2'      'd2'      'e2'      'f2' ]
+  [  'a3'      'b3'      'c3'      'd3'      'e3'      'f3' ]
+  [  'a4'      'b4'      'c4'      'd4'      'e4'      'f4' ]
+  [  'a5'      'b5'      'c5'      'd5'      'e5'      'f5' ]
+  [  'a6'      'b6'      'c6'      'd6'      'e6'      'f6' ]
+  [  'a7'      'b7'      'c7'      'd7'      'e7'      'f7' ]
+  [  'a8'      'b8'      'c8'      'd8'      'e8'      'f8' ]
+  [  'a9'      'b9'      'c9'      'd9'      'e9'      'f9' ]
+]
+
+const enumerated_table = [
+  [ index      col-a     col-b     col-c     col-d     col-e     col-f ];
+  [   0         'a0'      'b0'      'c0'      'd0'      'e0'      'f0' ]
+  [   1         'a1'      'b1'      'c1'      'd1'      'e1'      'f1' ]
+  [   2         'a2'      'b2'      'c2'      'd2'      'e2'      'f2' ]
+  [   3         'a3'      'b3'      'c3'      'd3'      'e3'      'f3' ]
+  [   4         'a4'      'b4'      'c4'      'd4'      'e4'      'f4' ]
+  [   5         'a5'      'b5'      'c5'      'd5'      'e5'      'f5' ]
+  [   6         'a6'      'b6'      'c6'      'd6'      'e6'      'f6' ]
+  [   7         'a7'      'b7'      'c7'      'd7'      'e7'      'f7' ]
+  [   8         'a8'      'b8'      'c8'      'd8'      'e8'      'f8' ]
+  [   9         'a9'      'b9'      'c9'      'd9'      'e9'      'f9' ]
+]
+
+export def "test row-indices-range" [] {
+  assert equal (
+    row-indices 0..3 10..11
+  ) (
+    [ 0 1 2 3 10 11 ]
+  )
+}
+
+export def "test row-indices-index" [] {
+  assert equal (
+    row-indices 4
+  ) (
+    [ 4 ]
+  )
+}
+
+export def "test row-indices-complex" [] {
+  assert equal (
+    row-indices 0..2..6 3 7
+  ) (
+    [ 0 2 4 6 3 7 ]
+  )
+}
+
+export def "test col-index-ints" [] {
+  assert equal (
+    # Third and Fifth Columns
+    $test_table | col-indices 2 4
+  ) (
+    [ 'col-c', 'col-e' ]
+  )
+}
+
+export def "test col-index-complex" [] {
+  assert equal (
+    # Every other column, plus the second
+    $test_table | col-indices 0..2..10 1
+  ) (
+    [ 'col-a', 'col-b', 'col-c', 'col-e' ]
+  )
+}
+
+export def "test select-range single-int" [] {
+  assert equal (
+    $test_table | select ranges 1
+  ) (
+    $enumerated_table | select 1
+  )
+}
+
+export def "test select-range single-range" [] {
+  assert equal (
+    $test_table | select ranges 2..4
+  ) (
+    $enumerated_table | select 2 3 4 
+  )
+}
+
+export def "test select-range complex" [] {
+  assert equal (
+    # First and every following third-row + second row
+    $test_table | select ranges 1 0..3..100
+  ) (
+    $enumerated_table | select 0 1 3 6 9
+  )
+}
+
+export def "test select-range out-of-bounds" [] {
+  assert equal (
+    $test_table | select ranges 100
+  ) (
+    []
+  )
+}
+
+export def "test reject-range single-index" [] {
+  assert equal (
+    $test_table | reject ranges 4
+  ) (
+    $enumerated_table | reject 4
+  )
+}
+
+export def "test reject-range ranges" [] {
+  assert equal (
+    # Reject rows 0-3 and 5-9, leaving only 4
+    $test_table | reject ranges 0..3 5..9
+  ) (
+    $enumerated_table | select 4
+  )
+}
+
+export def "test reject-range out-of-bounds" [] {
+  assert error {
+    $test_table | reject ranges 1000
+  }
+}
+
+export def "test select-col index" [] {
+  assert equal (
+    $test_table | select column-ranges 2
+  ) (
+    $test_table | select col-c
+  )
+}
+
+export def "test select-col indices" [] {
+  assert equal (
+    $test_table | select column-ranges 2 4
+  ) (
+    $test_table | select col-c col-e
+  )
+}
+
+export def "test select-col ranges-and-index" [] {
+  assert equal (
+    $test_table | select column-ranges 0..2..5 1
+  ) (
+    $test_table | select col-a col-c col-e col-b
+  )
+}
+
+export def "test reject-col ranges-and-index" [] {
+  assert equal (
+    $test_table | reject column-ranges 0..2..5 1
+  ) (
+    $enumerated_table | select col-d col-f
+  )
+}
+
+export def "test reject-col out-of-bounds" [] {
+  assert equal (
+    $test_table | reject column-ranges 1_000
+  ) (
+    $test_table
+  )
+}