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# ====================================================================================
# Functions
# ====================================================================================
# The last statement of a function is implictly returned. Parenthesis for functions
# are optional as long as the statement can be envaluated disambiguously.
repl do
puts "* RUBY PRIMER: Functions"
end
# ====================================================================================
# Functions single parameter
# ====================================================================================
repl do
puts "* INFO: Function with one parameter"
# function definition
def add_one_to n
n + 1
end
# Parenthesis are optional in Ruby as long as the
# parsing is disambiguous. Here are a couple of variations.
# Generally speaking, don't put parenthesis is you don't have to.
# Conventional Usage of Parenthesis.
puts add_one_to(3)
# DragonRuby's recommended use of parenthesis (inner function has parenthesis).
puts (add_one_to 3)
# Full parens.
puts(add_one_to(3))
# Outer function has parenthesis
puts(add_one_to 3)
end
# ====================================================================================
# Functions with default parameter values
# ====================================================================================
repl do
puts "* INFO: Function with default value"
def function_with_default_value v = 10
v * 10
end
puts "Passing the argument three yields: #{function_with_default_value 3}"
puts "Passing no argument yields: #{function_with_default_value}"
end
# ====================================================================================
# Nil default parameter value and ||= operator.
# ====================================================================================
repl do
puts "* INFO: Using the OR EQUAL operator (||=)"
def function_with_nil_default_with_local a = nil
result = a
result ||= "DEFAULT_VALUE_OF_A_IS_NIL_OR_FALSE"
"value is #{result}."
end
puts "Passing 'hi' as the argument yields: #{function_with_nil_default_with_local 'hi'}"
puts "Passing nil: #{function_with_nil_default_with_local}"
end
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