Hi –
I’ve put together some RDoc-style documentation for the Ruby keywords.
It’s at http://www.wobblini.net/keywords.
It’s artificially presented in method-doc format, even though they’re
not methods, because that helped me write it and see what it looked
like. I don’t know what the best way to package and distribute it
properly is (obviously not as methods), and would be interested in
suggestions.
David
David A. Black wrote:
Sweet.
It would be nice if this (or something like it) was part of the Ruby
source such that generating the regular rdoc would emit this as well,
and linked in some obvious way from the index.
In any event, I’d like to host this on ruby-doc.org.
–
James B.
www.jamesbritt.com - Playing with Better Toys
www.ruby-doc.org - Ruby Help & Documentation
www.rubystuff.com - The Ruby Store for Ruby Stuff
www.neurogami.com - Smart application development
David A. Black wrote:
Hi –
I’ve put together some RDoc-style documentation for the Ruby keywords.
It’s at http://www.wobblini.net/keywords.It’s artificially presented in method-doc format, even though they’re
not methods, because that helped me write it and see what it looked
like. I don’t know what the best way to package and distribute it
properly is (obviously not as methods), and would be interested in
suggestions.
http://www.ruby-doc.org/docs/keywords/1.9/
–
James B.
www.jamesbritt.com - Playing with Better Toys
www.ruby-doc.org - Ruby Help & Documentation
www.rubystuff.com - The Ruby Store for Ruby Stuff
www.neurogami.com - Smart application development
David A. Black [email protected] wrote:
Hi –
I’ve put together some RDoc-style documentation for the Ruby keywords.
It’s at http://www.wobblini.net/keywords.
Not true that rescue “Must occur either inside a begin/end
block or a method definition (which implies begin).”
Counterexample:
puts “first line”
raise “oops” rescue puts “no problem”
puts “last line”
Or has this changed in 1.9? I focus on rescue because discovering this
single-expression version of rescue is not easy for beginners. m.
Hi –
On Tue, 30 Jun 2009, Matt N. wrote:
Counterexample:
puts “first line”
raise “oops” rescue puts “no problem”
puts “last line”Or has this changed in 1.9? I focus on rescue because discovering this
single-expression version of rescue is not easy for beginners. m.
It’s still there – I’ll add it. Thanks.
David
Hi –
On Tue, 30 Jun 2009, Rob B. wrote:
Since its related to ‘rescue’, I’ll point out that you can also use ‘else’ to
indicate code that only gets executed if none of the rescue clauses are
(i.e., there is no exception). This is, of course, not like ‘ensure’ with is
executed regardless.This point should be added to ‘else’ even if it refers to the rescue and/or
ensure docs (which don’t mention this use of ‘else’ either).
Very timely reminder – I’m now going to go back and revise an answer
I gave someone here a couple of hours ago 
(And I’ll add it to the
document too.)
David
On Jun 29, 2:35 pm, Rob B. [email protected]
wrote:
Since its related to ‘rescue’, I’ll point out that you can also use
‘else’ to indicate code that only gets executed if none of the rescue
clauses are (i.e., there is no exception). This is, of course, not
like ‘ensure’ with is executed regardless.
Really? This is the first I’ve heard of this, and it seems kind of
strange.
Maybe I’m misunderstanding the point of the ‘else’ clause, but
wouldn’t you put code that “only gets executed if none of the rescue
clauses are (i.e., there is no exception)” in the main body of what
you’re adding rescues to? (viz. begin block, method definition)
On Jun 29, 2009, at 3:50 PM, Yossef M. wrote:
Maybe I’m misunderstanding the point of the ‘else’ clause, but
wouldn’t you put code that “only gets executed if none of the rescue
clauses are (i.e., there is no exception)” in the main body of what
you’re adding rescues to? (viz. begin block, method definition)–
-yossef
If there is something that isn’t valid in the face of an exception and
for which you do not want to catch any exceptions, but must occur
prior to the ensure block.
begin
a
b
rescue => ex
c
else
d
ensure
e
end
If doing d is only valid if b completes, and assuming that (x) means
an exception happens during x, the possible sequences are:
(a),c,e
(a),©,e
a,(b),c,e
a,(b),©,e
a,b,d,e
a,b,(d),e
Note that d happens before e, but (d) does not cause the rescue clause
to be invoked.
I know that I’ve run into the practical need for this at least once
(but there were several rescue clauses, not just one). If I could
recall the specific example, I’d have put it in.
-Rob
Yossef M. wrote:
wouldn’t you put code that “only gets executed if none of the rescue
clauses are (i.e., there is no exception)” in the main body of what
you’re adding rescues to? (viz. begin block, method definition)
Counterexample:
begin
puts "According to your theory, this shouldn’t be evaluated, "
puts “but it will.”
raise RuntimeError
rescue
else
puts “This, however, won’t.”
end
jwm
On Jun 29, 2009, at 3:19 PM, David A. Black wrote:
It’s at http://www.wobblini.net/keywords.
Ruby/Rails consulting & training: http://www.rubypal.com
Now available: The Well-Grounded Rubyist (http://manning.com/black2)
“Ruby 1.9: What You Need To Know” Envycasts with David A. Black
http://www.envycasts.com
Since its related to ‘rescue’, I’ll point out that you can also use
‘else’ to indicate code that only gets executed if none of the rescue
clauses are (i.e., there is no exception). This is, of course, not
like ‘ensure’ with is executed regardless.
This point should be added to ‘else’ even if it refers to the rescue
and/or ensure docs (which don’t mention this use of ‘else’ either).
-Rob
On Jun 29, 3:35 pm, Jörg W Mittag [email protected]
wrote:
puts “but it will.”
raise RuntimeError
rescue
else
puts “This, however, won’t.”
end
I could have explained that better. I was thinking more along the
lines of
begin
puts "This will be executed, "
puts "as will this."
raise
puts "This, however, won't."
rescue
else
put "And neither will this."
end
Rob’s a-e example points out the benefit of using the else clause, but
it’s still strange and slippery to me. I’ve never run into a practical
need for it, though I’m not inclined to disbelieve him when he says he
has. It would be great to see a concrete example.
Hi –
On Tue, 30 Jun 2009, Jörg W Mittag wrote:
Maybe I’m misunderstanding the point of the ‘else’ clause, but
rescue
else
puts “This, however, won’t.”
end
I think Yossef is talking about a case where something like this:
begin
require ‘something’
rescue LoadError
puts “Sorry”
else
m = Something.new
end
could be done like this instead:
begin
require ‘something’
m = Something.new
rescue LoadError
puts “Sorry”
end
There’s another thread going in which I’ve stumbled through several
iterations of advice to someone about exactly this problem, and
essentially ended up with that last one. A great example of
cross-thread heterodyning
David
On Jun 29, 3:43 pm, “David A. Black” [email protected] wrote:
could be done like this instead:
begin
require ‘something’
m = Something.new
rescue LoadError
puts “Sorry”
end
Basically, yes.
There’s another thread going in which I’ve stumbled through several
iterations of advice to someone about exactly this problem, and
essentially ended up with that last one. A great example of
cross-thread heterodyning
I saw that. One thing that could be said about the
begin
require 'something'
rescue LoadError
puts "Sorry"
else
m = Something.new
end
example is that it gets the exception out of the way quickly and then
you can easily see the body of code that matters. That order makes it
clear that the begin/rescue is only to safely wrap the optional code
that would execute if you only had the right library present (or gem
installed).
On the other hand, structuring it as
begin
require 'something'
m = Something.new
rescue LoadError
puts "Sorry"
end
would leave you hanging if the optional code is substantial. You could
have to look down a bit before realizing why the begin block was even
there.
On Jun 28, 2009, at 20:39, David A. Black wrote:
I’ve put together some RDoc-style documentation for the Ruby keywords.
It’s at http://www.wobblini.net/keywords.It’s artificially presented in method-doc format, even though they’re
not methods, because that helped me write it and see what it looked
like. I don’t know what the best way to package and distribute it
properly is (obviously not as methods), and would be interested in
suggestions.
Using RDoc 2 will remove all the spurious links for common words like
not, in, or, etc. (To force links, use #not, #in, #or, etc.)
Hi –
On Tue, 30 Jun 2009, Eric H. wrote:
Using RDoc 2 will remove all the spurious links for common words like not,
in, or, etc. (To force links, use #not, #in, #or, etc.)
Cool. Do you think there’s a fundamentally better way to do the whole
thing than these phony method definitions? (def false, etc.) I like
having them split up, method-fashion, but it’s a kluge.
David
On Jun 29, 2009, at 17:45, “David A. Black” [email protected] wrote:
Cool. Do you think there’s a fundamentally better way to do the whole
thing than these phony method definitions? (def false, etc.) I like
having them split up, method-fashion, but it’s a kluge.
In RDoc 2 you can use directives to make methods:
But it still would need to live somewhere like Object (at least IIRC)
On Jun 29, 2009, at 7:43 PM, James B. wrote:
Cool, thanks for the effort. But there is a typo on the main page:
1.9 keywords
Keywwords defined in 1.9.
“w” is a cool letter, but it can be overused ;).
Regards,
Florian
:method: false
blah blah comment
:method: or
etc.
Hmm. Could I request a full file example of how to use :method: ? The
following saved as an rb file doesn’t seem to work…
=r
class Socket
module Tutorial
end
end
class Array
end
Florian G. wrote:
Keywwords defined in 1.9.
“w” is a cool letter, but it can be overused ;).
Thwanks, I wwill fwix it.
–
James B.
www.jamesbritt.com - Playing with Better Toys
www.ruby-doc.org - Ruby Help & Documentation
www.rubystuff.com - The Ruby Store for Ruby Stuff
www.neurogami.com - Smart application development
Hi –
On Wed, 1 Jul 2009, Florian G. wrote:
Keywwords defined in 1.9.
“w” is a cool letter, but it can be overused ;).
That’s what we call a “quadruple-u”. It’s a near-relation of the
famous sextuple-u you see in so many URLs
David
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