Tony Garnock-Jones uploaded a new version of Collections to project The Trunk:
http://source.squeak.org/trunk/Collections-tonyg.971.mcz

==================== Summary ====================

Name: Collections-tonyg.971
Author: tonyg
Time: 23 December 2021, 3:28:05.944561 pm
UUID: 0c4855b6-dd88-4b87-bb0c-7b07120d8364
Ancestors: Collections-tonyg.970

Allow extraction of a Matrix column even when there are no rows in the matrix.

=============== Diff against Collections-tonyg.970 ===============

Item was changed:
  ----- Method: Matrix>>atColumn: (in category 'accessing rows/columns') -----
  atColumn: column
  	|p|
+ 	nrows = 0 ifTrue: [
+ 		(column between: 1 and: ncols)
+ 			ifFalse: [self error: '2nd subscript out of range'].
+ 		^ #()].
- 
  	p := (self indexForRow: 1 andColumn: column)-ncols.
  	^(1 to: nrows) collect: [:row | contents at: (p := p+ncols)]
  !