Doesn't unspace work for this? On Wednesday, March 3, 2010, Darren Duncan <dar...@darrenduncan.net> wrote: > pugs-comm...@feather.perl6.nl wrote: > > Modified: > docs/Perl6/Spec/S02-bits.pod > Log: > [S02] remove 1/2 and +2-3i literal forms, now rely on angle dwimmery for > literals, > or constant folding otherwise. > > <snip> > > I find this an interesting change, and I can see how it would simplify some > things, even though I would miss the old behavior. > > But this reminds me of what I see as a tangential issue, which I want to > raise. > > How would Perl 6 support someone wanting to write a numeric literal that is > so long that they would want to split it over multiple source code lines, > such as a very long integer that takes a few hundred or thousand characters > to write, or an X/Y rational composed of 2 such integers, but they want to > keep their source code under the 80 chars per line mark. > > I'm not currently aware that Perl 6 provides some kind of "continuation > marker" that one could put between pieces of such a literal, so that they > could split those pieces otherwise with whitespace but then the parser would > treat the code as if said whitespace wasn't there, but I think Perl 6 should > have this. It would need to work both outside any quoting constructs as well > as inside any angle dwimmery. > > On one hand I would think the mnemonics of "~", which are stitching things > together, would work great for a continuation marker, but that "~" seems to > already be established in Perl 6 as indicating a string data context, such > that it is used for casting things into Str or catenating 2 strings. > However, I will use "~" below for the sake of illustration. > > my $some_pi = 3.141592653589793238462643383279 > ~ 5028841971693993751058209749445923078164 > ~ 0628620899862803482534211706798214808651 > ~ 3282306647093844609550582231725359408128; > my $a_rat = <48111745028410270193 > ~ 8521105559/64462294895493038196 > ~ 442881097566593344612847564823>; > > As a slight extension to this, one should be able to use that same > continuation character between 2 consecutive string literals so that they are > parsed as if they were one string literal, so that one could also split those > over source code lines, without the vaguarities of source code line endings > affecting the value of the string like a here-doc or literal line breaks > would. I grant that this could be redundant with regular constant folding of > the already defined "~" operator, but using the continuation marker instead > for this could spare concern about precedence issues same as <1/2> does > versus 1/2 after today's changes. > > my $a_string = 'hello this world' > ~ ' how are you today'; > > Now I think in the wider world some precedent exists for using the > logical-not character ¬ as a continuation marker, but that isn't an ASCII > symbol and we would want something ASCII for the continuation marker. Also I > think using the backslash for such a marker would be a bad idea. > > While this isn't an operator per se, if it had to be put in the precedence > table, I would think it would have the highest possible precedence; it would > be eliminated during one of the earliest parsing phases, during tokenization > I believe, and then all the other parsing rules would come into effect > following that elimination, except for the big one that any literal > continuation chars inside a quoted string are taken as normal characters as > usual. > > So can we please have this continuation marker thing, and what do you think > it should look like? > > Thank you in advance. > > -- Darren Duncan > >
-- Mark J. Reed <markjr...@gmail.com>
