Beginners question: branching and ends

trying to figure out exactly where ‘end’ needs to be in my code. I’m
using Scite and find that often time it will report ‘expecting kEND’
at the last line of the code and not where the kEND should actually
be. It would be nice if there was more accuracy but I won’t expect
it.

so if this is my code

somearray.each do |x|
anotherarray.each do |y|
if x == y
…do something…
else
…do something…
end # I have this ‘end’ for the if/else statement
end # this ‘end’ is for the somearray loop
end # and this is the one question, but I’m guessing (i know not
good to guess) that this # one is needed for the
anotherarray loop ?

Would this be correct ? One thing I’ve found is that having the right
number of ends will make the code execute but having them in the wrong
place will have surprising results.

TIA
Stuart

   if x == y

number of ends will make the code execute but having them in the wrong
place will have surprising results.

nods Looks just fine to me.

Stuart;

I’ve taken the liberty of reformating your code here. It is really
important you you indent things correctly so that you can see the
structure of the code clearly. You’ll see that I’ve added lines to in
the columns showing each construct and it’s matching end tag:

somearray.each do |x|
| anotherarray.each do |y|
| | if x == y
| | | # …do something…
| | else
| | | # …do something…
| | end
| end
end

See? As you suspected, the first end is paired up with the if/else
construct. As indented above; however, you can plainly see how the
end keywords match up with their controlling constructs. It turns out
that you had the meaning of the last two ends switched in your
comments.

Everything needs to be properly nested. That is, you need to end the
first do block before you can end the enclosed one.

I hope that helps a little.

On Jun 28, 2006, at 13:01, Dark A. wrote:

trying to figure out exactly where ‘end’ needs to be in my code. I’m
using Scite and find that often time it will report ‘expecting kEND’
at the last line of the code and not where the kEND should actually
be. It would be nice if there was more accuracy but I won’t expect
it.

You shouldn’t expect it - it’s a hard thing to catch that sort of
error in a compiler or interpreter. Think of it this way:

begin
begin
begin
begin
# end <- oops!
end
end
end

The mistake is the ‘end’ commented out, but to the interpreter, the
only missing one is at the very end, since the three 'end’s that
exist match the first three 'begin’s. Because Ruby’s very liberal
when it comes to what statements you can make and where (e.g., nested
methods), it might not be clear there’s an ‘end’ missing until the
end of the file, and even then, there’s no simple way to tell which
‘end’ is actually missing, just that one is.

end # and this is the one question, but I’m guessing (i know not
good to guess) that this # one is needed for the
anotherarray loop ?

Would this be correct ? One thing I’ve found is that having the right
number of ends will make the code execute but having them in the wrong
place will have surprising results.

That’s not correct: the first end corresponds to the ‘if/else’, but
you have the other ones mixed up: the second end corresponds to
anotherarray.each, and the third one corresponds to somearray.each.
Think of it like nested boxes or Russian dolls: each begin/end block
is contained inside an outer one:

begin # 1
begin # 2
begin # 3
end # 3
end # 2
end # 1

As an interesting note, this is one of the ways in which keeping your
code indented properly makes things easier for you in the long run -
you can actually see which ‘end’ aligns to which ‘begin’. The major
benefit of proper indentation is that it makes life easier for people
on the mailing list who have to read your code.

matthew smillie.

2006/6/28, Louis J Scoras [email protected]:

Everything needs to be properly nested. That is, you need to end the
first do block before you can end the enclosed one.

Just adding to that: every IDE will have a hard time figuring out
where exactly you missed an end. That’s next to impossible. For
example

foo.each do |x|
x.each do |a|
puts a
end # assume this was missing
puts x.size
end

No ide could guess whether the “end” was missing in the marked line or
in the line after “puts x.size” (which could be any other statement or
sequence of statements).

That’s why Ruby usually complains at the end of the file. A good way
to prevent this is to create the habit of entering all pairs
(brackets, if then end, do end etc.) immediately before entering the
code between them. Or use an IDE that does it for you.

Kind regards

robert

Helps a great deal! TY. I do use indentation and the odd thing is when
I cut/paste into the email , the indentation remains intact. I’m not
sure what gmail is doing (if anything) once it gets sent.

Stuart

I’ve found that GMail often mucks up code for whatever reason. You
should
check out nopaste1 or pastebin2.

|| Dean

On Wednesday 28 June 2006 18:52, Dean S. wrote:

I’ve found that GMail often mucks up code for whatever reason. You should
check out nopaste[1] or pastebin[2].

Sorry to deviate from the original question, but I’d like to say that
whether
gmail messes up indenting or not, it’s better to put code in your
mailing
list email because 1) people don’t have to open their browser to see
what
you’re talking about and 2) If someone is looking through the archives,
they
can still read your code (paste bin sites normally expire pastes after
24-72hours).

Alex

Sorry to deviate from the original question, but I’d like to say that
whether

gmail messes up indenting or not, it’s better to put code in your
mailing

list email because 1) people don’t have to open their browser to see what
you’re talking about and 2) If someone is looking through the archives,
they
can still read your code (paste bin sites normally expire pastes after
24-72hours).

This is a valid point, but I’ve given up on threads because the code
gets
mangled. I guess maybe the ultimate answer here is put your code in the
message, and if you’re nice, pastebin it too.

[/tangent]

|| Dean

Plain text

On 6/28/06, Dark A. [email protected] wrote:

Helps a great deal! TY. I do use indentation and the odd thing is when
I cut/paste into the email , the indentation remains intact. I’m not
sure what gmail is doing (if anything) once it gets sent.

Ahh, yes. I assumed that the indenting in the message was correct
because there was some indenting in there. Weird that gmail would
mess that up. Are you posting using plain text or ‘rich formatting’?

This forum is not affiliated to the Ruby language, Ruby on Rails framework, nor any Ruby applications discussed here.

| Privacy Policy | Terms of Service | Remote Ruby Jobs