ruby-dev summary 21637-21729

[Takaaki Tateishi]

Hello,

I present you a summary of the ruby-dev mailing list.

[ruby-dev:21639] load() blocks thread scheduling
Tietew posted the following scripts which didn't timeout and didn't
accept Ctrl+C.

-- main.rb --
require 'timeout'
timeout(60) { load 'block.rb' }

--- block.rb
loop { }

He also posted a patch to change the thread. Matz wrote that
it would cause unexpected troubles if we didn't block other
thread while loading a script.


[ruby-dev:21641] SOAP::StreamError: Illegal media type
SOAP4R's test suite failed since it required pre-installed SOAP4R
library. Matz suggested that the test suite in ruby should use
not pre-installed libraries but use archived new libraries from
the archive.


[ruby-dev:21678] Problems of testing test/drb on Windows
U. Nakamura showed two opinions about test/drb on Windows as follows.
(a) test/drb/test_drbunix.rb failed if it was executed via
test/runner.rb, since Windows didn't have Socket::UNIX*.
He thought that such error had better occur when loading
'drb/unix'.
(b) The result of test/drb/test_acl.rb was 'E', since the
ruby was compiled without AF_INET6 and IPAddr#ipv6?
caused NameError. He proposed some solutions to avoid
NameError.


[ruby-dev:21679] Proposal: string literal concatenation
Mput proposed a specification which enables us to concatenate
strings using a new line like the following script.

s = "foo1" "bar1"
"foo2" "bar2"

Matz answered that he will discard string literal concatenation.


[ruby-dev:21682] ruby-tk hangs when exception is raised

Akira Yamada received a bug report as a package maintainer of
Debian. The following Ruby/TK script caused a problem that
Ctrl+C was not available. This problem have not been solved yet.

require 'tk'
r = TkRoot.new
b = TkButton.new(r) { text "break me" }
b.command proc {
raise "error!"
}
b.pack
Tk.mainloop

--
Takaaki Tateishi <ttate@ttsky.net>

[Paul Brannan]

On Fri, Oct 31, 2003 at 07:01:28AM +0900, Takaaki Tateishi wrote:

> [ruby-dev:21679] Proposal: string literal concatenation
> Mput proposed a specification which enables us to concatenate
> strings using a new line like the following script.
>
> s = "foo1" "bar1"
> "foo2" "bar2"
>
> Matz answered that he will discard string literal concatenation.

So what will the result of the above two lines of code be?

Paul

[Yukihiro Matsumoto]

Hi,

In message "Re: ruby-dev summary 21637-21729"
on 03/11/06, Paul Brannan <pbrannan@atdesk.com> writes:

|On Fri, Oct 31, 2003 at 07:01:28AM +0900, Takaaki Tateishi wrote:
|> [ruby-dev:21679] Proposal: string literal concatenation
|> Mput proposed a specification which enables us to concatenate
|> strings using a new line like the following script.
|>
|> s = "foo1" "bar1"
|> "foo2" "bar2"
|>
|> Matz answered that he will discard string literal concatenation.
|
|So what will the result of the above two lines of code be?

Plain syntax error in 1.9.x.

matz.

[Paul Brannan]

On Thu, Nov 06, 2003 at 11:17:59PM +0900, Yukihiro Matsumoto wrote:

> In message "Re: ruby-dev summary 21637-21729"
> on 03/11/06, Paul Brannan <pbrannan@atdesk.com> writes:
> |So what will the result of the above two lines of code be?
>
> Plain syntax error in 1.9.x.

Is the syntax error because of the first line or because of the second?
I ask because I do this a lot in my code:

s = "this is a string " \
"that I have chosen to break " \
"into multiple lines

I would be happy to switch to using heredocs if there were an easy way
to indent heredocs.

Paul

[Yukihiro Matsumoto]

Hi,

In message "Re: ruby-dev summary 21637-21729"
on 03/11/06, Paul Brannan <pbrannan@atdesk.com> writes:

|Is the syntax error because of the first line or because of the second?

Both. Sequence of strings will no longer be valid.

|I ask because I do this a lot in my code:
|
| s = "this is a string " \
| "that I have chosen to break " \
| "into multiple lines"

How about

s = "this is a string " +
"that I have chosen to break " +
"into multiple lines"
?

matz.

[Paul Brannan]

On Fri, Nov 07, 2003 at 12:36:23AM +0900, Yukihiro Matsumoto wrote:

> In message "Re: ruby-dev summary 21637-21729"
> on 03/11/06, Paul Brannan <pbrannan@atdesk.com> writes:
> |
> | s = "this is a string " \
> | "that I have chosen to break " \
> | "into multiple lines"
>
> How about
>
> s = "this is a string " +
> "that I have chosen to break " +
> "into multiple lines"

This works, but the concatenation is done at run-time instead of at
compile-time.

Paul

[Robert Church]

On Fri, Nov 07, 2003 at 07:57:32AM +0900, Paul Brannan quipped:

> > How about
> >
> > s = "this is a string " +
> > "that I have chosen to break " +
> > "into multiple lines"

>
> This works, but the concatenation is done at run-time instead of at
> compile-time.

Or so you assume. I don't know how Matz will handle this, but there's
no reason concatenation of string constants could not be done at
compile time.

[Eric Hodel]

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Robert Church (rc@pgdn.org) wrote:

> On Fri, Nov 07, 2003 at 07:57:32AM +0900, Paul Brannan quipped:

> > > How about
> > >=20
> > > s =3D "this is a string " +
> > > "that I have chosen to break " +
> > > "into multiple lines"

> >=20
> > This works, but the concatenation is done at run-time instead of at
> > compile-time.

>=20
> Or so you assume. I don't know how Matz will handle this, but there's
> no reason concatenation of string constants could not be done at
> compile time.

You can redefine String#+, so no such optimization must be made at
compile time.

--=20
Eric Hodel - [email]drbrain@segment7.net[/email] - [url]http://segment7.net[/url]
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[gabriele renzi]

il Fri, 7 Nov 2003 07:57:32 +0900, Paul Brannan <pbrannan@atdesk.com>
ha scritto::

>This works, but the concatenation is done at run-time instead of at
>compile-time.

well, this could be meaningful if ruby had a real compiling fase.
And if it had it this could be esailt solved from the compiler (I
think javac does this, for example)

[Sean O'Dell]

On Thursday 06 November 2003 07:36 am, Yukihiro Matsumoto wrote:

> Hi,
>
> In message "Re: ruby-dev summary 21637-21729"
>
> on 03/11/06, Paul Brannan <pbrannan@atdesk.com> writes:
> |Is the syntax error because of the first line or because of the second?
>
> Both. Sequence of strings will no longer be valid.
>
> |I ask because I do this a lot in my code:
> |
> | s = "this is a string " \
> | "that I have chosen to break " \
> | "into multiple lines"
>
> How about
>
> s = "this is a string " +
> "that I have chosen to break " +
> "into multiple lines"
> ?

My 1 cent: I really wish "" \ style concatenation wouldn't go away.

Sean O'Dell

[nobu.nokada@softhome.net]

Hi,

At Fri, 7 Nov 2003 07:57:32 +0900,
Paul Brannan wrote:

> On Fri, Nov 07, 2003 at 12:36:23AM +0900, Yukihiro Matsumoto wrote:

> > In message "Re: ruby-dev summary 21637-21729"
> > on 03/11/06, Paul Brannan <pbrannan@atdesk.com> writes:
> > |
> > | s = "this is a string " \
> > | "that I have chosen to break " \
> > | "into multiple lines"
> >
> > How about
> >
> > s = "this is a string " +
> > "that I have chosen to break " +
> > "into multiple lines"

>
> This works, but the concatenation is done at run-time instead of at
> compile-time.

In 1.8, this is concatenated at compile-time. :)

s = "this is a string #{ # And you can write
""}that I have chosen to break #{ # comments!
""}into multiple lines"

--
Nobu Nakada

[Joel VanderWerf]

[email]nobu.nokada@softhome.net[/email] wrote:

> In 1.8, this is concatenated at compile-time. :)
>
> s = "this is a string #{ # And you can write
> ""}that I have chosen to break #{ # comments!
> ""}into multiple lines"
>

Very cool! It doesn't need the "", though, does it?

irb(main):001:0> "foo#{
irb(main):002:0" }bar"
=> "foobar"

[nobu.nokada@softhome.net]

Hi,

At Fri, 7 Nov 2003 10:42:51 +0900,
Joel VanderWerf wrote:

> > In 1.8, this is concatenated at compile-time. :)
> >
> > s = "this is a string #{ # And you can write
> > ""}that I have chosen to break #{ # comments!
> > ""}into multiple lines"
> >

>
> Very cool! It doesn't need the "", though, does it?
>
> irb(main):001:0> "foo#{
> irb(main):002:0" }bar"
> => "foobar"

It needs for compile-time concatenation, because nil.to_s might
be replaced.

$ ruby -rNodeDump -e '"foo#{' -e '}bar"'
NodeDump V0.9

NODE_NEWLINE: [-e:1]
NODE_DSTR: "foo"
NODE_EVSTR:
NODE_STR: "bar"

$ ruby -rNodeDump -e '"foo#{' -e '""}bar"'
NodeDump V0.9

NODE_NEWLINE: [-e:1]
NODE_STR: "foobar"

This optimization is limited to the case #{} ends with a
literal string (and preceding literals without any side
effects)

--
Nobu Nakada

[Yukihiro Matsumoto]

Hi,

In message "Re: ruby-dev summary 21637-21729"
on 03/11/07, Paul Brannan <pbrannan@atdesk.com> writes:

|This works, but the concatenation is done at run-time instead of at
|compile-time.

Don't worry. It's done at run-time anyway.

matz.

[Yukihiro Matsumoto]

Hi,

In message "Re: ruby-dev summary 21637-21729"
on 03/11/07, "Sean O'Dell" <sean@celsoft.com> writes:

|My 1 cent: I really wish "" \ style concatenation wouldn't go away.

Why?

matz.

[Laurent Sansonetti]

Hi,

Yukihiro Matsumoto wrote:

> Hi,
>
> In message "Re: ruby-dev summary 21637-21729"
> on 03/11/06, Paul Brannan <pbrannan@atdesk.com> writes:
>
> |Is the syntax error because of the first line or because of the second?
>
> Both. Sequence of strings will no longer be valid.
>
> |I ask because I do this a lot in my code:
> |
> | s = "this is a string " \
> | "that I have chosen to break " \
> | "into multiple lines"
>
> How about
>
> s = "this is a string " +
> "that I have chosen to break " +
> "into multiple lines"

I would prefer this:

s = "this is a string "
+ "that I have chosen to break "
+ "into multiple lines"

I think it's always better to avoid operators in the end of lines (code
is therefore more readeable).

Same think for this:

if ( expr1...
and expr2...
and expr3... )

# do something
end

But AFAIK && unfortunately, Ruby does not handle this kind of syntax yet.

Matz, what do you think about this?

Thanks,

--
Laurent

[Tim Bates]

On Fri, Nov 07, 2003 at 06:04:47PM +0900, Laurent Sansonetti wrote:

> I think it's always better to avoid operators in the end of lines (code
> is therefore more readeable).
>
> But AFAIK && unfortunately, Ruby does not handle this kind of syntax yet.

Because of Ruby's line-based syntax, Ruby guesses that if you have hit
the end of the line and the line as a whole is valid, then you have
finished that statement. This is essentially a limitation of the parser.
There are two ways around this - require statements to end with a
special character (eg a semicolon) so that if we get to the end of the
line and haven't found that character yet we know the statement isn't
finished, or implement look-ahead in the parser to take a look at the
next line and see if it, when combined with the current line, is a valid
statement as a whole. This is a lot more difficult; it involves
look-ahead and creates a whole new family of ambiguities; e.g. what do
you do if the next line creates a valid statement when combined with
this line, and also the two lines are valid statements by themselves? So
if the alternative is to require every statement to end in a semicolon
(noooo!) which takes a significant chunk out of the beauty of the
language, I must say that I prefer the way it is done now - and the same
applies to most of Matz's decisions, which is why I love this language.

Tim Bates
--
[email]tim@bates.id.au[/email]

[Yukihiro Matsumoto]

In message "Re: ruby-dev summary 21637-21729"
on 03/11/07, Laurent Sansonetti <laurent@datarescue.be> writes:

|I would prefer this:
|
|s = "this is a string "
| + "that I have chosen to break "
| + "into multiple lines"
|
|I think it's always better to avoid operators in the end of lines (code
|is therefore more readeable).
|
|Same think for this:
|
|if ( expr1...
| and expr2...
| and expr3... )
|
| # do something
|end
|
|But AFAIK && unfortunately, Ruby does not handle this kind of syntax yet.
|
|Matz, what do you think about this?

There's always trade-off. Newline sensitive syntax do not allow
line concatenation by operator at the beginning of a line, e.g. how
can we distinguish

s = "this is a string "
+ "that I have chosen to break "
+ "into multiple lines"

which is a single assignment statement, from

s = "this is a string "
+ "that I have chosen to break "
+ "into multiple lines"

an assignment followed by two unary plus expression?

matz.

[T. Onoma]

> > | s = "this is a string " \

> > | "that I have chosen to break " \
> > | "into multiple lines"
> >
> > How about
> >
> > s = "this is a string " +
> > "that I have chosen to break " +
> > "into multiple lines"

>
> I would prefer this:
>
> s = "this is a string "
> + "that I have chosen to break "
> + "into multiple lines"

shades of %L and kin

[T. Onoma]

> > Both. Sequence of strings will no longer be valid.

> >
> > |I ask because I do this a lot in my code:
> > |
> > | s = "this is a string " \
> > | "that I have chosen to break " \
> > | "into multiple lines"

how will this 'fect HERE docs?

print <<HERE
Double quoted \
here document.
HERE