ruby - Is there a difference between @var = var_val and self.send("var=", var_val)? -

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when initialize instance variables in initialize method, there difference between using @var = var_value , self.send("var=", var_value)? mean, there reason prefer 1 way on other reason, if means style reason?

class mysuperclass   attr_accessor :columns, :options end  class mysubclass < mysuperclass   def initialize(columns, options)     @columns = columns     @options = options   end end  class myothersubclass < mysuperclass   def initialize(columns, options)     self.send("columns=", columns)     self.send("options=", options)   end end

there difference.

@var = x assigns instance variable. there no method call. there no virtual dispatch. there no (sane) way of intercepting assignment.

send invokes method (or "sends message"). in context, :var= assessor "setter method" wraps instance variable assignment. it's method, invoked via virtual dispatch honoring inheritance, , - including being overridden in subtypes.

the true equivalent @var = x instance_variable_set:

self.instance_variable_set(:@var, x)

using send in case odd. use accessor directly (self.columns = columns) if intent.

as 1 "more correct" depends on level of encapsulation established - , contracts defined on types , usages thereof. err on side of accessors when subtypes involved.


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