Feature #4935

Quoted Label Form for 1.9 Hashes

Added by Michael Edgar almost 3 years ago. Updated over 1 year ago.

Assignee:Yukihiro Matsumoto
Target version:next minor


As discussed in the "Shorthand Hash Syntax for Strings" thread/feature request, several (including Matz) expressed interest in a parallel quoted form for the 1.9 label syntax:

{ foo: bar }
{ 'only-19': true }

x = "hello"
{ "#{x}-world": Date.now }

This personally has come up for me with the new syntax: especially when dealing with command-line options, which often use hyphens, the quoted symbol form is necessary. Not being able to use the new syntax results in funny-looking hashes:

{ foo: bar, baz: qux, :'abc-def' => 1 }

I've attached a patch implementing this change. It allows a colon to follow single-quoted or double-quoted string literals to form a symbol key much like the label syntax introduced in 1.9. The examples listed at the start of this post all work fine. It introduces a new token - tLABELEND - which replaces tSTRINGEND when closing a symbol-label-literal. It introduces a single new grammar production for assoc, which is nearly purely syntactic sugar for the dsym grammar production; I've extracted dsym's implementation to a separate helper function, which is called from the dsym production and from the new label-style production.

I will immediately attach a new passing test for test_hash.rb in a followup post, once this has a feature # and ruby-core thread assigned to it.

NB: By removing the quote check on line 6580, one can make this feature work with any string literal (like "{ %q/foo-bar/: baz}", obviously doesn't work with heredocs) - I personally find this to be silly and inconsistent with the existing symbol syntax. Though it was fun to play with for a bit.

label_patch.diff Magnifier - Implementation (4.07 KB) Michael Edgar, 06/27/2011 11:28 AM

label_test.diff Magnifier - Test for the implementation of this feature. (541 Bytes) Michael Edgar, 06/27/2011 11:31 AM

Related issues

Duplicates ruby-trunk - Feature #4276: Allow use of quotes in symbol syntactic sugar for hashes Assigned 01/13/2011


#1 Updated by Michael Edgar almost 3 years ago

Sorry, meant to list this as a feature. Test attached.

#2 Updated by Shyouhei Urabe almost 3 years ago

  • Tracker changed from Bug to Feature

#3 Updated by Michael Edgar almost 3 years ago

With the feature freeze coming up in a couple days, is there a chance this sees 1.9.3? It doesn't break any old syntax, only introduces new syntax, and rounds out the label feature of the 1.9 branch nicely.

#4 Updated by Yusuke Endoh about 2 years ago

  • Status changed from Open to Assigned
  • Assignee set to Yukihiro Matsumoto

#5 Updated by Yusuke Endoh over 1 year ago

  • Target version set to next minor

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