So the method below in class_eval dynamically creates accessors for attributes defined at runtime. It can be used, for example, to create configuration objects with attributes read from a config file (and unknown until runtime). I understanding all of it except for the else branch. If I am correct the else branch returns the attribute value (val[0]) if there is one value passed in *val. However the way its written I would expect it to return an array (val) if there is more then one value passed in *var. In particular, if I have something like the following:
value = 5
then from reading the code I would expect @value to be [=,5]
. However @value
returns 5 and not the array [=,5]. How is this possible?
class Module
def dsl_accessor(*symbols)
symbols.each do |sym|
class_eval %{
def #{sym}(*val)
if val.empty?
@#{sym}
else
开发者_如何学JAVA @#{sym} = val.size == 1 ? val[0] : val
end
end
}
end
end
end
An equals sign is not an argument for the method, it's a part of the method name. Actually you can call an assignment like this:
value=(5)
So only the integer 5 is an argument for the function.
class Module
def dsl_accessor(*symbols)
symbols.each do |sym|
class_eval %{
def #{sym}
@#{sym}
end
def #{sym}=(val)
@#{sym} = val
end
}
end
end
end
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