Ruby’s most basic control structure: if statement
if @writable
@author = "josdem"
end
Consider, however, what would happen if we turned the logic around: If the document is read only, the natural tendency would be to simply throw in a ! or not:
if not @read_only
@author = "josdem"
end
An more idiomatic way would be:
unless @read_only
@author = "josdem"
end
The body of the statement is executed only if the condition is false.
In the same way we avoid negative conditions in while loops. Thus it is not:
while ! parking_lot.is_full?
park += 1
end
it’s:
until parking_lot.is_full?
park +=1
end
Using modifier forms
Let’s return to this snippet code:
unless @read_only
@author = "josdem"
end
We should collapse the whole thing into a single line like this:
@author = "josdem" unless @read_only
You can also do similar things with while
park +=1 while parking_lot.has_space?
Using Each
beers = ['IPA', 'Lagrimas Negras', 'Calavera']
beers.each do |beer|
puts beer
end
Case Statement
framework = case language
when 'Groovy'
puts 'Grails'
when 'Ruby'
puts 'Rails'
else
puts 'I Do Not Know'
end
This is equivalent and more compact:
framework = case language
when 'Groovy' then 'Grails'
when 'Ruby' then 'Rails'
else 'I Do Not Know'
Another expression-based way to make decision is the ternary operator.
activity = programmer ? 'Java' : 'Futbol'
If the value of programmer is true, then the value of the whole expression is the thing between the question mark and colon, if the condition is false, the the expression evaluates the last part.