Mixing
Rails optional validation ambiguous
I discovered that this validation still works
validates :name, presence: true, if: (spa) -> { spa.name_required && other_name.blank? }
This has a lambda with an argument, but the argument isn't used for the other_name check
I found that when I removed the argument to the lambda it still works
validates :name, presence: true, if: -> { name_required && other_name.blank? }
The documentation says we should be creating procs, see https://guides.rubyonrails.org/active_record_validations.html#using-a-symbol-with-if-and-unless
I think this works because a lambda is a closure inside the object it's defined so the object's methods are available.
Question is, why does the Active Record documentation say use a proc with an argument? Is using a lambda like this wrong in some way?
ruby-on-rails validation activerecord
asked Nov 19 '18 at 14:41
Ghoti
2,20611519
add a comment |
I discovered that this validation still works
validates :name, presence: true, if: (spa) -> { spa.name_required && other_name.blank? }
This has a lambda with an argument, but the argument isn't used for the other_name check
I found that when I removed the argument to the lambda it still works
validates :name, presence: true, if: -> { name_required && other_name.blank? }
The documentation says we should be creating procs, see https://guides.rubyonrails.org/active_record_validations.html#using-a-symbol-with-if-and-unless
I think this works because a lambda is a closure inside the object it's defined so the object's methods are available.
Question is, why does the Active Record documentation say use a proc with an argument? Is using a lambda like this wrong in some way?
ruby-on-rails validation activerecord
asked Nov 19 '18 at 14:41
Ghoti
2,20611519
A lambda is bound to its context so the implicitselfis the same as the outer context where it was defined. In this caseselfis the model instance. I think this is just a case of the documentation being old or poorly written as it does not really matter if you use a proc or lambda as long as you understand the differences.
– max
Nov 19 '18 at 17:36
I think so too, max, but using a lambda is much less clumsy looking :)
– Ghoti
Nov 20 '18 at 14:52
add a comment |
I discovered that this validation still works
validates :name, presence: true, if: (spa) -> { spa.name_required && other_name.blank? }
This has a lambda with an argument, but the argument isn't used for the other_name check
I found that when I removed the argument to the lambda it still works
validates :name, presence: true, if: -> { name_required && other_name.blank? }
The documentation says we should be creating procs, see https://guides.rubyonrails.org/active_record_validations.html#using-a-symbol-with-if-and-unless
I think this works because a lambda is a closure inside the object it's defined so the object's methods are available.
Question is, why does the Active Record documentation say use a proc with an argument? Is using a lambda like this wrong in some way?
ruby-on-rails validation activerecord
asked Nov 19 '18 at 14:41
Ghoti
2,20611519
I discovered that this validation still works
validates :name, presence: true, if: (spa) -> { spa.name_required && other_name.blank? }
This has a lambda with an argument, but the argument isn't used for the other_name check
I found that when I removed the argument to the lambda it still works
validates :name, presence: true, if: -> { name_required && other_name.blank? }
The documentation says we should be creating procs, see https://guides.rubyonrails.org/active_record_validations.html#using-a-symbol-with-if-and-unless
I think this works because a lambda is a closure inside the object it's defined so the object's methods are available.
Question is, why does the Active Record documentation say use a proc with an argument? Is using a lambda like this wrong in some way?
ruby-on-rails validation activerecord
ruby-on-rails validation activerecord
asked Nov 19 '18 at 14:41
Ghoti
2,20611519
asked Nov 19 '18 at 14:41
Ghoti
2,20611519
asked Nov 19 '18 at 14:41
Ghoti
2,20611519
asked Nov 19 '18 at 14:41
Ghoti
2,20611519
asked Nov 19 '18 at 14:41
Ghoti
2,20611519
2,20611519
A lambda is bound to its context so the implicitselfis the same as the outer context where it was defined. In this caseselfis the model instance. I think this is just a case of the documentation being old or poorly written as it does not really matter if you use a proc or lambda as long as you understand the differences.
– max
Nov 19 '18 at 17:36
I think so too, max, but using a lambda is much less clumsy looking :)
– Ghoti
Nov 20 '18 at 14:52
add a comment |
A lambda is bound to its context so the implicitselfis the same as the outer context where it was defined. In this caseselfis the model instance. I think this is just a case of the documentation being old or poorly written as it does not really matter if you use a proc or lambda as long as you understand the differences.
– max
Nov 19 '18 at 17:36
I think so too, max, but using a lambda is much less clumsy looking :)
– Ghoti
Nov 20 '18 at 14:52
A lambda is bound to its context so the implicit
self is the same as the outer context where it was defined. In this case self is the model instance. I think this is just a case of the documentation being old or poorly written as it does not really matter if you use a proc or lambda as long as you understand the differences.– max
Nov 19 '18 at 17:36
A lambda is bound to its context so the implicit
self is the same as the outer context where it was defined. In this case self is the model instance. I think this is just a case of the documentation being old or poorly written as it does not really matter if you use a proc or lambda as long as you understand the differences.– max
Nov 19 '18 at 17:36
I think so too, max, but using a lambda is much less clumsy looking :)
– Ghoti
Nov 20 '18 at 14:52
I think so too, max, but using a lambda is much less clumsy looking :)
– Ghoti
Nov 20 '18 at 14:52
add a comment |
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A lambda is bound to its context so the implicit
selfis the same as the outer context where it was defined. In this caseselfis the model instance. I think this is just a case of the documentation being old or poorly written as it does not really matter if you use a proc or lambda as long as you understand the differences.– max
Nov 19 '18 at 17:36
I think so too, max, but using a lambda is much less clumsy looking :)
– Ghoti
Nov 20 '18 at 14:52