This is the second time in the past few days I've been told to use two spaces instead of tabs. Can anyone provide any insight as to what difference this makes?
Unlike in some other communities, there is no contention in the Ruby community over whether to use two, four or eight spaces. Everyone is happy to use just two. Furthermore, never use tabs, which includes the practice of mixing tabs with spaces.
That's not to say spaces are better than tabs, or two spaces are better than four spaces. Just that idiomatic Ruby code uses two spaces.
Two spaces are always two spaces.
key <tab> => <tab> value
This might look perfectly fine for someone using 8-width tabs, but it will most likely be screwy for anyone using 4-width tabs or smaller. The tab's location is calculated as the distance where the cursor position modulo the tab width is 0.
E.g. one key is 2 chars long and another is 5 chars long. You tabbed it using 8-width tabs. Looks fine. If someone loads it with 4-width tabs, they see the two lines aligned differently.
#!/usr/bin/ruby -w
#-*- standard-indent: 2; indent-tabs-mode: nil; -*-