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13:34 < Luckys> how do I differ a Block and a Proc I can't understand that
thingy at all :(
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13:37 < kig> block is syntax sugar for giving a method a proc as an argument
13:37 < ngw> hi *
13:37 < multi_io> you're right, the difference between blocks and procs in Ruby
is quite non-intuitive (some say it's badly designed)
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13:38 < neoneye> proc is being replaced by lambda
13:38 < multi_io> right, so blocks are also just anonymous functions, but with
a more pleasant syntax
13:39 < Luckys> I'm seeing the examples on Chris Pine's site which are making
me confused
13:39 < kig> (0..10).each{|i| puts i} is about the same as
(0..10).each(&proc{|i| puts i}) , the & is used for turning a
proc into a block argument
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13:41 < kig> without blocks the syntax to do the things they do would be more
verbose: (0..10).my_map(proc{|i| i*2}).my_sort(proc{|x,y| y<=>x})
13:41 < Luckys> kig: I'm just 2 days old in ruby :)
13:41 < multi_io> kig: one could just make {|args..|body...} the syntax for all
anonymous functions. problem solved.
13:42 < kig> multi_io: yeah, i was thinking about the same thing
13:42 < Luckys> but in all the examples that I worked from this site, none
carry braces {} can they be used the way you guys are saying
13:43 < kig> the problem that might arise there is disambiguating {1=>2, 3=>4}
and {|args| body}
13:43 < kig> but now that i look at them, they are visually enough apart from
each other to read properly
13:44 < multi_io> Luckys: {|args| body} is another syntax for do |args| body end
13:44 < flgr> multi_io: though that raises a syntax collision with Hashes, more
or less
13:45 < kig> flgr: it's not a big collision, /\{\s*\|/ vs /\{\s*[^|]/ if you
pardon my regexp
13:46 < multi_io> {42} is also a proc...
13:46 < dblack> kig: what about {} ?
13:46 < kig> oh right
13:46 < kig> forgot those
13:47 < multi_io> but just 3=>4 isn'
13:47 < multi_io> t valid ruby code
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13:50 < kig> puts [1,2,3,4]; puts {1=>2, 3=>4};
13:50 < flgr> kig: what about emtpy argument lists?
13:50 < flgr> what about { {1 => 2} }
13:50 < flgr> and so on
13:50 < flgr> I think it is possible, but not completely simple
13:50 < flgr> but I doubt that this is the only reason for Ruby not using it
13:51 < flgr> I'm not using Ruby for a long time and foo = { 1 + 2 } already
looks odd for me
13:51 < kig> yes
13:51 < flgr> that must be way more intense for matz
13:51 < flgr> plus there's still the difference between [1, 2, 3].each({ |x| p
x }) and [1, 2, 3].each { |x| p x }
13:52 < kig> the hash-block syntax collision is happening today too (the puts
example). could it be fixed?
13:52 < flgr> I think so.
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13:54 < kig> one way might be to drop the preceding | from block argument list,
and make the argument list mandatory (though now only one char
long when there are no args). feels kinda ugly though. hrm. each{|
puts "hi!"}, map{x,y| x*y}
13:56 < kig> or the longer each{|| do stuff}
13:56 < kig> don't really like either all that much
13:57 < kig> are literal blocks used more than literal hashes
13:57 < kig> if yes, then the hash syntax should change, mayhaps
13:57 < multi_io> I still don't see the problem.. hash literals always contain
=>, ruby code blocks never do. So they should be
distinguishable, no?
14:00 < multi_io> (albeit harder to parse)
14:00 < kig> can't think of a counterexample, so yeah, i guess.
14:00 < kig> it can also be a ",", but that doesn't really pose a problem either
14:01 < Luckys> I think its enough for today for me understand ruby, leaving
proc and blocks for tomorrow, cuz I'm exhausted as of now
14:01 < kig> since {1,2} isn't a valid block
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14:01 < kig> Luckys: sorry for going on a tangent from to proc-block discussion
:I
14:01 < Luckys> I appreciate the patience you guys have in here
14:01 < multi_io> Luckys: it's quite esotheric anyway, you'll use blocks 98% of
the time :=)
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14:01 < kig> s/to/the
14:02 < Luckys> kig: may be that made me confused, so I'll leave for tomorrow,
and startup fresh
14:03 < Luckys> One thing I liked of ruby was of extending the class, its
fairly simple the "self" thing
14:04 < multi_io> I guess the puts {1=>2, 3=>4} problem is because the ruby
parser works "1-token-lookahead"
14:05 < Luckys> how do ruby can be compared with other scripting language(s)
like perl or python
14:05 < multi_io> i.e. when it sees "{" after a name, it decides that a block
follows without looking further
14:06 < multi_io> a parser that distinguishes hash literals from blocks by
looking for => couldn't be 1-token-lookahead...
back to ruby
(C) 1998-2017 Olaf Klischat <olaf.klischat@gmail.com>