[ruby-core:77266] [Ruby trunk Bug#12758] Error when passing Hash construction to function

Issue #12758 has been updated by _ wanabe.


This is in FAQ.
Please see http://ruby-doc.org/docs/ruby-doc-bundle/FAQ/FAQ.html#s6 : "6.7 Why can't I pass a hash literal to a method: p {}?"

And you can pass a hash to method without braces when it is last argument.

```
irb(main):001:0> p a: 1
{:a=>1}
=> {:a=>1}
irb(main):002:0> p 1 => 2
{1=>2}
=> {1=>2}
irb(main):003:0> p a: 1, 2
SyntaxError: (irb):3: syntax error, unexpected '\n', expecting =>
	from /usr/local/bin/irb:11:in `<main>'
irb(main):004:0>
```

----------------------------------------
Bug #12758: Error when passing Hash construction to function
https://bugs.ruby-lang.org/issues/12758#change-60497

* Author: Jimi Damon
* Status: Open
* Priority: Normal
* Assignee: 
* ruby -v: ruby 2.1.3p242 (2014-09-19 revision 47630) [x86_64-linux]
* Backport: 2.3: UNKNOWN
----------------------------------------
I apologize if this is a known issue but I couldn't find it in the search.


If you have a function that can take a Hash, it behaves correctly if you pass a variable that contains the Hash compared to when you pass in a Hash construction using braces {}. 

Example

def foo(a)
  puts a.class
  puts a
end

> foo [1,2]
Array
[1, 2]
> a = { a:1 }
> foo a 
Hash
{:a=>1}

# This breaks
> foo { a:1 }

SyntaxError: (irb):23: syntax error, unexpected ':', expecting '}'
foo {a:1}
       ^

but this works

> foo( {a:1} )
Hash
{:a=>1}


This is more of a bug related to consistent syntax of the language and it is something that is allowed in Groovy and Scala










-- 
https://bugs.ruby-lang.org/

Unsubscribe: <mailto:[e-mail]?subject=unsubscribe>
<http://lists.ruby-lang.org/cgi-bin/mailman/options/ruby-core>