# Ruby -w and '(...) interpreted as grouped expression'

**URL:** <https://www.ruby-forum.com/t/ruby-w-and-interpreted-as-grouped-expression/79825>\
**Category:** Ruby\
**Created:** [March 11, 2006, 9:19am UTC](https://www.ruby-forum.com/t/ruby-w-and-interpreted-as-grouped-expression/79825 "2006-03-11T09:19:47Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![pool007](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/p/3bc359/32.png) [@pool007](https://www.ruby-forum.com/u/pool007)\
**Post date:** [March 11, 2006, 9:19am UTC](https://www.ruby-forum.com/t/ruby-w-and-interpreted-as-grouped-expression/79825/1 "2006-03-11T09:19:47Z")

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Hi all.

I’ve encountered enigmatic error message while learning rdoc. This is  
the simple program which tests RDoc:

#!/usr/local/bin/ruby -w

# == Synopsis

# Test synopsis

require “optparse”  
require “rdoc/usage”

opts = OptionParser.new  
opts.on("-h", “–help”) { RDoc::usage }  
opts.parse(ARGV) rescue RDoc::usage(‘usage’)

puts “hello”

When I run above program like ‘./test.rb’, ruby says  
“/usr/local/lib/ruby/1.8/rdoc/ri/ri\_formatter.rb:46: warning: (…)  
interpreted as grouped expression”

Why is this warning raised? I have no idea what grouped expression is.

Sincerely,  
Minkoo S.

---

<div class="post-metadata">

**Author:** ![pool007](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/p/3bc359/32.png) [@pool007](https://www.ruby-forum.com/u/pool007)\
**Post date:** [March 11, 2006, 9:25am UTC](https://www.ruby-forum.com/t/ruby-w-and-interpreted-as-grouped-expression/79825/2 "2006-03-11T09:25:49Z")

</div>

Hi,

In message “Re: ruby -w and ‘(…) interpreted as grouped expression’”  
on Sat, 11 Mar 2006 17:18:47 +0900, “Minkoo S.”  
[removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) writes:

|When I run above program like ‘./test.rb’, ruby says  
|“/usr/local/lib/ruby/1.8/rdoc/ri/ri\_formatter.rb:46: warning: (…)  
|interpreted as grouped expression”  
|  
|Why is this warning raised? I have no idea what grouped expression is.

It’s caused by a space before argument parenthesis. I just removed it  
from the source code. Thank you.

```
						matz.

```