I''ve seen a few examples of how us the link_to and I''ve read
the API
documentation.
It seems that the API docs would recommend that when using this
method, the best practice would be to write it as follows:
<%= link_to "This is FooBar", { :controller => "foo",
:action =>
"bar"} %>
But outside the API documentation, I''ve seen the method called as
follows...
<%= link_to( ''this is foobar'', :controller =>
''foo'', :action => ''bar'')
%>
I prefer the second way because it seems more readable, but since the
API docs don''t describe calling the method like this I''m
wondering if
it''s unsupported.
Is there a best practice for how to call this method? Why?
Thanks,
Pat
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Hi Pat, The answer to your wonderment isn''t particular to Rails but is a function of Ruby''s flexibility in passing in arguments to a method. The link_to method has four formal arguments, the first of which is required. The second and third both have default values (which the assume in absence of the prescence of a second and third argument, respectively) and the fourth represents a multi-valued argument where any amount of arguments greater than the first three are collected into an array and passed as the last argument. As for the answer to your question, I bet there is a best practice because Rails is typically opinionated software. My guess would be that it is the first way which is best practice because it is a common Rails idiom and, IMO, more sincere to the intent of the arguments. Obviously, the second way works but looking at the source code, I''m not exactly sure why it works. I''m going to have to step through with a debugger so let me say thanks for the interesting question. After stepping through the debugger, I see that in your second example, the second two arguments (:controller => "foo", :action => "bar") are considered part of one hash and are passed to url_for as the first argument(in this file http://api.rubyonrails.org/files/vendor/rails/actionpack/lib/action_view/helpers/url_helper_rb.html - NOTE: the link didn''t display source code for me but at least points you in the correct file for the source code, your local install location of the source code may vary). Maybe someone with better understanding of ruby than I can explain why the second two arguments are considered part of one has as opposed to two? (I would assume its something to do with the binding priority of ''=>'' and its subsequent effects? I wouldn''t think a symbol is the trigger. Or is it that both strings and controllers objects have an operator (method) ''=>'' which takes in an argument and returns a hash object? How would I verify my supposition? Is there a ruby compiler with ruby source code? Or do I go try to grok C code?)] Thanks, Jonathan On Sep 6, 11:16 pm, Pat <mill...-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> wrote:> I''ve seen a few examples of how us the link_to and I''ve read the API > documentation. > > It seems that the API docs would recommend that when using this > method, the best practice would be to write it as follows: > > <%= link_to "This is FooBar", { :controller => "foo", :action => > "bar"} %> > > But outside the API documentation, I''ve seen the method called as > follows... > > <%= link_to( ''this is foobar'', :controller => ''foo'', :action => ''bar'') > %> > > I prefer the second way because it seems more readable, but since the > API docs don''t describe calling the method like this I''m wondering if > it''s unsupported. > > Is there a best practice for how to call this method? Why? > > Thanks, > Pat--~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "Ruby on Rails: Talk" group. To post to this group, send email to rubyonrails-talk-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org To unsubscribe from this group, send email to rubyonrails-talk-unsubscribe-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org For more options, visit this group at http://groups.google.com/group/rubyonrails-talk?hl=en -~----------~----~----~----~------~----~------~--~---
Hi Pat, The answer to your wonderment isn''t particular to Rails but is a function of Ruby''s flexibility in passing in arguments to a method. The link_to method has four formal arguments, the first of which is required. The second and third both have default values (which they assume in absence of the prescence of a second and third argument, respectively) and the fourth represents a multi-valued argument where any amount of arguments greater than the first three are collected into an array and passed as the last argument. As for the answer to your question, I bet there is a best practice because Rails is typically opinionated software. My guess would be that it is the first way which is best practice because it is a common Rails idiom and, IMO, more sincere to the intent of the arguments. Obviously, the second way works but looking at the source code, I''m not exactly sure why it works. I''m going to have to step through with a debugger so let me say thanks for the interesting question. After stepping through the debugger, I see that in your second example, the second two arguments (:controller => "foo", :action => "bar") are considered part of one hash and are passed to url_for as the first argument(in this file http://api.rubyonrails.org/files/vendor/rails/actionpack/lib/action_v... - NOTE: the link didn''t display source code for me but at least points you in the correct file for the source code, your local install location of the source code may vary). Maybe someone with better understanding of ruby than I can explain why the second two arguments are considered part of one hash as opposed to two one element hashes? (I would assume its something to do with the binding priority of ''=>'' and its subsequent effects? I wouldn''t think a symbol is the trigger. Or is it that both strings and symbol objects have an operator (method) ''=>'' which takes in an argument/expression and returns a hash object? How would I verify my supposition? Is there a ruby compiler with ruby source code? Or do I go try to grok C code?)] Thanks, Jonathan On Sep 6, 11:16 pm, Pat <mill...-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> wrote:> I''ve seen a few examples of how us the link_to and I''ve read the API > documentation. > > It seems that the API docs would recommend that when using this > method, the best practice would be to write it as follows: > > <%= link_to "This is FooBar", { :controller => "foo", :action => > "bar"} %> > > But outside the API documentation, I''ve seen the method called as > follows... > > <%= link_to( ''this is foobar'', :controller => ''foo'', :action => ''bar'') > %> > > I prefer the second way because it seems more readable, but since the > API docs don''t describe calling the method like this I''m wondering if > it''s unsupported. > > Is there a best practice for how to call this method? Why? > > Thanks, > Pat--~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "Ruby on Rails: Talk" group. To post to this group, send email to rubyonrails-talk-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org To unsubscribe from this group, send email to rubyonrails-talk-unsubscribe-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org For more options, visit this group at http://groups.google.com/group/rubyonrails-talk?hl=en -~----------~----~----~----~------~----~------~--~---
On Sep 7, 6:22 am, Jonathan Wallace <jonathan.wall...-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> wrote:> Hi Pat, > The answer to your wonderment isn''t particular to Rails but is a > function of Ruby''s flexibility in passing in arguments to a method. > The link_to method has four formal arguments, the first of which is > required. The second and third both have default values (which they > assume in absence of the prescence of a second and third argument, > respectively) and the fourth represents a multi-valued argument where > any amount of arguments greater than the first three are collected > into an array and passed as the last argument. > > As for the answer to your question, I bet there is a best practice > because Rails is typically opinionated software. My guess would be > that it is the first way which is best practice because it is a common > Rails idiom and, IMO, more sincere to the intent of the arguments. > > Obviously, the second way works but looking at the source code, I''m > not exactly sure why it works. I''m going to have to step through with > a debugger so let me say thanks for the interesting question. > > After stepping through the debugger, I see that in your second > example, the second two arguments (:controller => "foo", :action => > "bar") are considered part of one hash and are passed to url_for as > the first argument(in this filehttp://api.rubyonrails.org/files/vendor/rails/actionpack/lib/action_v... > - NOTE: the link didn''t display source code for me but at least points > you in the correct file for the source code, your local install > location of the source code may vary). > > Maybe someone with better understanding of ruby than I can explain why > the second two arguments are considered part of one hash as opposed to > two one element hashes? (I would assume its something to do with the > binding priority > of ''=>'' and its subsequent effects? I wouldn''t think a symbol is the > trigger. Or is it that both strings and symbol objects have an > operator (method) ''=>'' which takes in an argument/expression and > returns a hash > object? How would I verify my supposition? Is there a ruby compiler > with ruby source code? Or do I go try to grok C code?)] > > Thanks, > Jonathan > > On Sep 6, 11:16 pm, Pat <mill...-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> wrote: > > > I''ve seen a few examples of how us the link_to and I''ve read the API > > documentation. > > > It seems that the API docs would recommend that when using this > > method, the best practice would be to write it as follows: > > > <%= link_to "This is FooBar", { :controller => "foo", :action => > > "bar"} %> > > > But outside the API documentation, I''ve seen the method called as > > follows... > > > <%= link_to( ''this is foobar'', :controller => ''foo'', :action => ''bar'') > > %> > > > I prefer the second way because it seems more readable, but since the > > API docs don''t describe calling the method like this I''m wondering if > > it''s unsupported. > > > Is there a best practice for how to call this method? Why? > > > Thanks, > > PatHi guys, Ruby allows you to omit the brackets when passing a hash as an argument to a method. This is only allowed when the hash is the last argument to the method. This is why the following two snippets are different, and will have different effects: <%= link_to "This is FooBar", :controller => "foo", :action =>"bar" %> <%= link_to "This is FooBar", { :controller => "foo"}, {:action =>"bar"} %> Cheers, Louis. --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "Ruby on Rails: Talk" group. To post to this group, send email to rubyonrails-talk-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org To unsubscribe from this group, send email to rubyonrails-talk-unsubscribe-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org For more options, visit this group at http://groups.google.com/group/rubyonrails-talk?hl=en -~----------~----~----~----~------~----~------~--~---