Issue #7854 has been updated by phluid61 (Matthew Kerwin).

File symbol_lookup.patch added

=begin
I've attached a patch that defines ((%Symbol[str]%)).  If ((|str|)) is a string and there exists a symbol such that (({symbol.to_s == str})), it returns that symbol.  Otherwise it returns ((|nil|)).  Raises a TypeError if ((|str|)) is not a string.

I also made a unit test, currently available as a gist: https://gist.github.com/phluid61/5105458
=end
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Feature #7854: New method Symbol[string]
https://bugs.ruby-lang.org/issues/7854#change-37348

Author: Student (Nathan Zook)
Status: Open
Priority: Normal
Assignee: matz (Yukihiro Matsumoto)
Category: core
Target version: next minor


I propose a new class method [] on Symbol.  If a symbol s already exists such that s.to_s == string, then s is returned.  If not, nil is returned.

The inspiration for this method is a question I was asked, and the answer I was given:  "Why would you want to turn a tainted string into a symbol?"  "I don't--I want to access an existing symbol with tainted data".  Symbol[] accesses the symbol table like hash[] accesses the elements of a hash.

I believe that this completely addresses the problems behind tickets #7791 and #7839.  I believe that it is a more intuitive solution than my proposal #7795, and I believe that this will also be useful for YAML.safe_load and similar initiatives.



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