Here is my code:
loop do
print "Input word: "
word = gets.chomp
if word.nil? or word.empty?
puts "Nothing to input."
else
if word.index(":") != -1
puts "Illegal character ':'"
else
break
end
end
end
Is there a more elegant way to check the input string?
Something like this?
loop do
print "Input word: "
word = gets.chomp
if word.empty?
puts "No input."
elsif word.include?(":")
puts "Illegal character ':'"
else
break
end
end
This separates the complex logic from the IO
def validation_message_for_word(word)
case
when (word.nil? or word.empty?) then "Nothing to input."
when word.include?(":") then 'Illegal character ":".'
else nil
end
end
word = nil # To ensure word doesn't get thrown away after the loop
loop do
print "Input word: "
word = gets.chomp
validation_message = validation_message_for_word(word)
break if validation_message.nil?
puts validation_message
end
Now, if you want to unit test it, you can give a variety of different strings to validation_message_for_word and test the return value.
If you needed internationalization, you could do
def validation_type_for_word(word)
case
when (word.nil? or word.empty?) then :no_input
when word.include?(":") then :illegal_character
else nil
end
end
def validation_message(language, validation_type)
{:en => {:no_input => "No input", :illegal_character => 'Illegal character ":"'},
:lolcat => {:no_input => "Invizibl input", :illegal_character => 'Character ":" DO NOT LIEK'}}.fetch(language).fetch(validation_type)
end
word = nil # To ensure word doesn't get thrown away after the loop
loop do
print "Input word: "
word = gets.chomp
validation_type = validation_type_for_word(word)
break if validation_type.nil?
puts validation_message(:lolcat, validation_type)
end
I personally prefer avoiding nested if/else:
loop do
print "Input word: "
word = gets.chomp
if word.nil? or word.empty?
puts "Nothing to input."
#break, exit, nothing, or whatever ....
end
if word.index(":") != 0
puts "Illegal character ':'"
else
break
end
end
elsif may be in order.Depends what "elegant" means to you, but as a fan of refactoring conditional statements to easily readable extracted methods, I'd look at something like:
def has_valid_input(word)
return true unless word.include?(":")
puts "Illegal."
return false
end
def is_not_empty(word)
return true unless word.empty?
puts "empty"
return false
end
loop do
print "Input word: "
word = gets.chomp
break if is_not_empty(word) && has_valid_input(word)
end
