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From: VMDD TECH on 2 Aug 2010 10:40
Hello everyone,

I am new to Ruby.

If there are spaces between new and (, then ruby 1.9.1p376 considers
it a syntactical error. For example:

File.new ("write.txt", "w+")

=>
syntax error, unexpected ',', expecting ')'
File.new ("write.txt", "w+")
^
....: syntax error, unexpected ')', expecting $end

Is this a ruby bug or is it a feature/quirk of ruby?

By the way, if I write as
File.new "write.txt", "w+"
File.new("write2.txt", "w+")

then there are no problem.

Thanks,

Binh
From: Joseph E. Savard on 2 Aug 2010 12:22
When using ( spaces are not required in 1.8.7 the error is
(irb):1: warning: don't put space before argument parentheses

In 1.9.2
SyntaxError: (irb):1: syntax error, unexpected ',', expecting ')'
f = File.open ("l.txt", "w+")

1.9.2 appears the error is a little obscure..

<MANISH.local:jes> [08-02] 0 517:17 (295.6 Mb) •
! irb
irb(main):001:0> f = File.open ("l.txt", "w+")
(irb):1: warning: don't put space before argument parentheses
=> #<File:l.txt>
irb(main):002:0> f = File.open("l.txt", "w+")
=> #<File:l.txt>
irb(main):003:0> f.write("<HTML></HTML>")
=> 13
irb(main):004:0> f.close
=> nil
irb(main):005:0> exit

<MANISH.local:jes> [08-02] 0 518:18 (295.6 Mb) •
! cat l.txt
<HTML></HTML>




> From: VMDD TECH <binhph(a)gmail.com>
> Organization: http://groups.google.com
> Reply-To: <ruby-talk(a)ruby-lang.org>
> Newsgroups: comp.lang.ruby
> Date: Mon, 2 Aug 2010 23:45:09 +0900
> To: ruby-talk ML <ruby-talk(a)ruby-lang.org>
> Subject: File.new ("write.txt", "w+") results in error
>
> Hello everyone,
>
> I am new to Ruby.
>
> If there are spaces between new and (, then ruby 1.9.1p376 considers
> it a syntactical error. For example:
>
> File.new ("write.txt", "w+")
>
> =>
> syntax error, unexpected ',', expecting ')'
> File.new ("write.txt", "w+")
> ^
> ...: syntax error, unexpected ')', expecting $end
>
> Is this a ruby bug or is it a feature/quirk of ruby?
>
> By the way, if I write as
> File.new "write.txt", "w+"
> File.new("write2.txt", "w+")
>
> then there are no problem.
>
> Thanks,
>
> Binh
>


From: Justin Collins on 2 Aug 2010 23:15
On 08/02/2010 07:45 AM, VMDD TECH wrote:
> Hello everyone,
>
> I am new to Ruby.
>
> If there are spaces between new and (, then ruby 1.9.1p376 considers
> it a syntactical error. For example:
>
> File.new ("write.txt", "w+")
>
> =>
> syntax error, unexpected ',', expecting ')'
> File.new ("write.txt", "w+")
> ^
> ...: syntax error, unexpected ')', expecting $end
>
> Is this a ruby bug or is it a feature/quirk of ruby?
>
> By the way, if I write as
> File.new "write.txt", "w+"
> File.new("write2.txt", "w+")
>
> then there are no problem.
>
> Thanks,
>
> Binh
>
>
It's not a bug. A comma-separated list inside of parentheses is just
meaningless in Ruby, which is why you get a syntax error.

Parentheses being "optional" for method calls is a feature, however.

-Justin

From: Brian Candler on 4 Aug 2010 05:51
Eugen Ciur wrote:
> File.new ("write.txt", "w+")
>
> =&gt;
> syntax error, unexpected ',', expecting ')'
> File.new ("write.txt", "w+")
> ^
> ...: syntax error, unexpected ')', expecting $end
>
> Is this a ruby bug or is it a feature/quirk of ruby?

The latter, because in ruby the parentheses surrounding the argument
list are optional.

Consider the difference here:

puts (2-3).abs ## means: puts((2-3).abs)
puts(2-3).abs ## means: (puts(2-3)).abs

[The latter fails, because puts returns nil, and nil.abs is not defined]

So if you include a space, the parentheses are considered part of the
first argument. If you don't include a space, the parentheses are
wrapping the argument list.

In ruby 1.8,
puts (2,3) ## accepted with warning
puts (2,3).abs ## syntax error

In ruby 1.9, they are both treated as a syntax error.
--
Posted via http://www.ruby-forum.com/.

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