Yup, simply use send (or, better yet, public_send) like so: arg1.public_send(op, arg2) This works because most operators in Ruby (including +, -, *, /, and more) simply call methods. So 1 + 2 is the same as 1.+(2). You may also want to whitelist op if it’s user input, e.g. %w[+ – * /].include?(op), as … Read more
Your regex, /\u(….)/, has some problems. First of all, \u doesn’t work the way you think it does, in 1.9 you’ll get an error and in 1.8 it will just match a single u rather than the \u pair that you’re looking for; you should use /\\u/ to find the literal \u that you want. … Read more
Posix character classes use a [:alpha:] notation, which are used inside a regular expression like: /[[:alpha:][:digit:]]/ You’ll need to scroll down a ways to get to the Posix information in the link above. From the docs: POSIX bracket expressions are also similar to character classes. They provide a portable alternative to the above, with the … Read more
Some random findings: [only in Ruby 2.3.0p0] The method doesn’t seem to exist: nil.method(:[]=) #=> NameError: undefined method `[]=’ nil.respond_to?(:[]=) #=> false And you can’t invoke it using send: nil.send(:[]=) #=> NoMethodError: undefined method `[]=’ Ruby evaluates neither the right hand side, nor the argument, i.e. nil[foo]=bar doesn’t raise a NameError, although foo and bar … Read more
This is one way to do it: class Superclass def before_each_method name p [:before_method, name] end def self.method_added name return if @__last_methods_added && @__last_methods_added.include?(name) with = :”#{name}_with_before_each_method” without = :”#{name}_without_before_each_method” @__last_methods_added = [name, with, without] define_method with do |*args, &block| before_each_method name send without, *args, &block end alias_method without, name alias_method name, with @__last_methods_added = … Read more
Ruby 1.9 #encoding: utf-8 “漢” =~ /\p{Han}/
This works in general: ceil(number*10)/10 So in Ruby it should be like: (number*10).ceil/10.0
Ruby has an Iconv library in its stdlib which converts encodings in a very similar way to the usual iconv command
One downside is that you would break the chained assignment semantics: $ irb irb(main):001:0> x = y = 3 => 3 irb(main):002:0> p x 3 => nil irb(main):003:0> p y 3 => nil irb(main):004:0> Consider: x = MyClass.property = 3 Then x would take true if this worked as you had expected (right-associativity). That could … Read more
The ambiguity between local variables and methods only arises for receiverless message sends with no argument list. So, the solution is obvious: either provide a receiver or an argument list: self.hello hello() See also How does ruby allow a method and a Class with the same name? Optional parens in Ruby for method with uppercase … Read more