Richard Hainsworth <rnhainswo...@gmail.com> wrote: > A semicolon is the syntax used for multidimensional arrays. > > See https://docs.perl6.org/language/subscripts#Multiple_dimensions
Thanks. I was trying to help Bill with that question, and I couldn't quite see what was going on there. You can't really do a web search on "<computer language>" and ";" and expect to learn anything. And reading through that section on multidimensional arrays, it doesn't immediately leap out why Bill would be seeing this behavior. It's mostly a discussion of dereferencing complex data structures, not creating them. Where it does create multiple levels it uses the comma. Richard Hainsworth <rnhainswo...@gmail.com> wrote: > A semicolon is the syntax used for multidimensional arrays. > > See https://docs.perl6.org/language/subscripts#Multiple_dimensions > > > On 14/04/2019 15:07, William Michels via perl6-users wrote: >> Hello, >> >> I've been working through Patrick Michaud's excellent videos from the >> The Perl Conference 2016. At about 35:45 of the following 2016 video >> (Part 1 of 2), Patrick discusses arrays: >> >> https://www.youtube.com/watch?v=ySch4xpoPA0 >> >> At this point in the video, Patrick also discusses push() and pop() >> calls on arrays. For practice I tried pushing and popping strings in >> the REPL. However, I discovered an unusual property when I misplaced a >> semicolon during call to push(). See what happens below when a >> semicolon is included within the parentheses of push(): >> >> "This is Rakudo version 2018.12 built on MoarVM version 2018.12 >> implementing Perl 6.d." >> >>> my @countries = "UK", "Spain", "Slovakia", "Sweden"; >> [UK Spain Slovakia Sweden] >>> @countries.push("Finland"); >> [UK Spain Slovakia Sweden Finland] >>> my @countries = "UK", "Spain", "Slovakia", "Sweden"; >> [UK Spain Slovakia Sweden] >>> @countries.push("Finland";) >> [UK Spain Slovakia Sweden (Finland) ()] >>> my @countries = "UK", "Spain", "Slovakia", "Sweden"; >> [UK Spain Slovakia Sweden] >>> @countries.push("Finland";); >> [UK Spain Slovakia Sweden (Finland) ()] >> >> Misplacing a semicolon within the push() call adds two elements to the >> array. When I examine these two elements, I see that they are both >> "List" elements: >> >>> @countries[3].WHAT >> (Str) >>> @countries[4].WHAT >> (List) >>> @countries[5].WHAT >> (List) >> >> Apparently, multiple semicolons within push() will add multiple list >> elements to the end of the intended array: >> >>> my @countries = "UK", "Spain", "Slovakia", "Sweden"; >> [UK Spain Slovakia Sweden] >>> @countries.push("Finland";;); >> [UK Spain Slovakia Sweden (Finland) () ()] >>> my @countries = "UK", "Spain", "Slovakia", "Sweden"; >> [UK Spain Slovakia Sweden] >>> @countries.push(;;;;;;;); >> [UK Spain Slovakia Sweden () () () () () () () ()] >> >> It is surprising to me that "List" elements are appended to the array >> with push() as described above. If one tries to add one or more >> elements via indexing and there 'aren't enough elements' so to speak >> (by accident or design), the array grows by inserting "Any" elements, >> not "List" elements: >> >>> my @countries = "UK", "Spain", "Slovakia", "Sweden"; >> [UK Spain Slovakia Sweden] >>> @countries[5] = "Finland"; >> Finland >>> say @countries >> [UK Spain Slovakia Sweden (Any) Finland] >>> my @countries = "UK", "Spain", "Slovakia", "Sweden"; >> [UK Spain Slovakia Sweden] >>> @countries[6..7] = "Finland", "Norway"; >> (Finland Norway) >>> say @countries >> [UK Spain Slovakia Sweden (Any) (Any) Finland Norway] >> >> I've briefly checked pop() to see if there are similar issues, but 1) >> placing a string within the parentheses of pop() will throw an error, >> and 2) placing a semicolon within the parentheses of pop() will throw >> an error. However, these error message are slightly different. A >> string argument to pop() will result in an error that says "Too many >> positionals passed; expected 1 argument but got 2" while a semicolon >> argument to pop() will result in an error that says "Too many >> positionals passed; expected 1 argument but got 3". >> >>> my @countries = "UK", "Spain", "Slovakia", "Sweden"; >> [UK Spain Slovakia Sweden] >>> @countries.pop("Finland") >> Too many positionals passed; expected 1 argument but got 2 >> in block <unit> at <unknown file> line 1 >> >>> @countries.pop(;) >> Too many positionals passed; expected 1 argument but got 3 >> in block <unit> at <unknown file> line 1 >> >> >> Any help appreciated, >> >> Bill. >> >> William Michels, Ph.D. >> >> PS Thanks to Joe Brenner for talking over this Perl6 code with me. >
