The Ruby Way: Solutions and Techniques in Ruby Programming (3rd Edition) (Addison-Wesley Professional Ruby Series)

Author:Hal Fulton & André Arko
Language: eng
Format: mobi
Publisher: Pearson Education
Published: 2015-02-10T22:00:00+00:00

def initialize(name)

@name = name

end

# ...

def to_s

"Pet: #@name"

end

end

Other methods (such as the String concatenation operator +) are more picky; they expect you to pass in something that is really pretty close to a String. In this case, Matz decided not to have the interpreter call to_s to convert non-string arguments because he felt this would lead to too many errors. Instead, the interpreter invokes a stricter method, to_str. Of the built-in classes, only String and Exception implement to_str, and only String, Regexp, and Marshal call it. Typically when you see the runtime error TypeError: Failed to convert xyz into String, you know that the interpreter tried to invoke to_str and failed.

You can implement to_str yourself. For example, you might want to allow numbers to be concatenated to strings:

Click here to view code image

class Numeric

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