Bug #11604: Ruby's interpreting hash symbol keys as parts of Ruby syntax

• Status: Rejected
• Assignee: matz (Yukihiro Matsumoto)
• Target version: -
• ruby -v: ruby 2.2.3p173 (2015-08-18 revision 51636) [x86_64-linux]

[maciej.mensfeld (Maciej Mensfeld)]

Cannot initialize hashes with some Ruby reserved keywords like: while, until, if, unless, do. Can with other like class, end, elsif, super. Don't really get why

{ while: 1 } # Will fail
# error.rb:3: syntax error, unexpected ':'
# print { while: 1 }

However when assigned, works perfectly

hash = { while: 1 }

But when used as a method argument - fails

run(for: 1)
run { for: 1 }

Works with old syntax

{ :if => 1 }

And with new but with quotation marks

{ 'if': 1 }

Example file included. Please just execute like this:

ruby error.rb

[shugo (Shugo Maeda)]

• Status changed from Open to Feedback

Maciej Mensfeld wrote:

Cannot initialize hashes with some Ruby reserved keywords like: while, until, if, unless, do. Can with other like class, end, elsif, super. Don't really get why

These syntax errors are not caused by key names, but by the use of { just after the method names.
The following code also causes a syntax error without the new style syntax of hash literals:

print { :while => 1 }

In this case, { is not interpreted as the beginning of a hash literal, but the beginning of a block, and thus a syntax error occurs.

[maciej.mensfeld (Maciej Mensfeld)]

That is true but IMHO it should still be considered as a bug.

[nobu (Nobuyoshi Nakada)]

• Status changed from Feedback to Rejected

Yes, it's your bug.