Great, now I'm trouble finding semicolon examples in PDL, too. (Bill: PDL is the "perl data language", a perl5 descendent of stuff like Matlab, which you'd probably recognize as being a bit like R.)
Larry Wall does discuss this stuff in the 9th Synopsis (one of the original design documents, which may be out-of-date): https://design.perl6.org/S09.html#The_semicolon_operator People talk about it here, too: https://grokbase.com/t/perl/perl6-language/05183ndht7/dimension-of-slices-scalars-versus-1-element-arrays On 4/14/19, yary <not....@gmail.com> wrote: > I don't know much about PDL (the Perl Data Lanuage) but I do remember that > the semicolon as a "higher-level" array separator in P6 is a nod to PDL. It > is a bit of stub feature until someone needs it and specs out, prototypes > more of that data-slicing style. It's likely under-documented due to that > history. > > -y > > > On Sun, Apr 14, 2019 at 10:29 AM Joseph Brenner <doom...@gmail.com> wrote: > >> 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. >> > >> >
