Use predefined string when Lexer.debug_enabled?

[ashmaroli]

Based on the following code:

rouge/lib/rouge/lexer.rb

Lines 309 to 314 in f494b53

	def initialize(opts={})
	@options = {}
	opts.each { |k, v| @options[k.to_s] = v }
	@debug = Lexer.debug_enabled? && bool_option(:debug)
	end

When Lexer.debug_enabled?, bool_option(:debug)will be called each time the Lexer is initialized, which in turn causes "debug" to be allocated for each instance. This can be avoided by using "debug" directly since that is the one globally supported option and other allocations can be reduced by caching into a local variable.

[jneen]

Can we not just use bool_option('debug') since we have frozen string literals?

[ashmaroli]

Can we not just use bool_option('debug') since we have frozen string literals?

We'd still have to handle "other options" passed in as symbols.
IMO, we should just use :to_sym here instead like we decided for lexers' state-names..
(because unlike to_s that will create a new object for every symbol converted, to_sym is going to generate just one object for every string converted. Moreover since the globally accepted option is documented as a symbol, the chances of receiving string option keys are minimal)

[jneen]

Except when we render from CGI options, as is common from markdown. Also, lexer options are untrusted data, so we need to be a little careful about casting them to symbols.

[jneen]

or any use of Lexer.find_fancy, which also uses CGI options...

[jneen]

Also, is that string not garbage collected later? This seems like a very premature optimization to me, especially for such a short string, whose data should be kept in the shared buffer.

[ashmaroli]

Garbage collection would be triggered more frequently if :debug.to_s was called multiple times.
I've updated the branch to use bool_option('debug') like you suggested, @jneen