On Tue, Mar 5, 2013 at 10:37 AM, Nicolas Desprès <[email protected]>wrote:
> > > On Mon, Mar 4, 2013 at 7:36 PM, Frederick Cheung < > [email protected]> wrote: > >> On Monday, March 4, 2013 12:59:23 PM UTC, Nicolas Desprès wrote: >> > Hi, >> > >> > >> > Constraints: >> > - The "id" function has to call "integer" and not "store_result" >> because it may be defined as a plugin. >> > - The functions must still raise ArgumentError as they already do. >> > >> > >> >> Could you give some examples of what you're trying to do or problems >> you've run into? You've posted some code but haven't described how you'll >> be using it and in what way it isn't adequate.In fewer words: I don't see >> what your question is. >> > > Thanks for replying. > > Yes sorry. I realize that some context is missing. > > # I am writing an API where the users are allowed to write something like > that: > > FooContextWithName.new.eval do |o| > o.integer "id", an_option: true # [1] > o.integer "foo", an_option: true # [2] > o.bar "a_name" do |o| > o.integer an_option: true # [3] > end > end > > # I would like that users are able to factor [1] and [2] by writing a > small plugin like this: > > module MyHelpers > def id(name = "id") > integer name, an_option: true > end > end > MyLib.add_helpers(MyHelpers) # add_helpers would be defined appropriately > > # To factor [3] users should be able to write something like that: > > module MyHelpers > def id > integer an_option: true > end > end > > # To implement this API I have something like this > > module DefWithName > def integer(name, options = {}) > store_result name, MyInteger.new(options) > end > end > > module DefWithoutName > def integer(options = {}) > store_result MyInteger.new(options) > end > end > > class FooWithName < BasicObject > include DefWithName > > def store_result(name, object) > @props[name] = object > end > end > > class BarWithoutName < BasicObject > include DefWithoutName > > def store_result(object) > @items << object > end > end > > =========================== > My goal is to provide a way for users to write their "id" method once and > to work in both cases. > > I am thinking about something like that: > > def id(*args) > if name_required? > name = name_given? ? given_name : "id" > end > > integer name, an_option: true > end > > def integer(*args) > value = MyInteger.new(options) > if name_required? > if name_given? > store_result given_name, value > else > raise ArgumentError > end > else > if name_given? > raise ArgumentError > end > store_result value > end > end > > where "name_required?", "given_name" and "name_given?" would be defined > appropriately based on the arguments passed to the method. > > I hope this is clearer now. > > I finally found a good way to factor this. Instead of having two modules DefWithoutName and DefWithName I have only one: module BasicDef def integer(name, options = {}) store_result name, MyInteger.new(options) end end Then I use a proxy for evaluation that will - in the case of "with name" will call directly the target method and pass it all the arguments - in the case of "without name" will call the target method by passing "nil" as first arguments and then the rest of the arguments. The proxy checks when the target method requires a name as first argument using the Method#parameters method. -- Nicolas Desprès -- You received this message because you are subscribed to the Google Groups "Ruby on Rails: Talk" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To post to this group, send email to [email protected]. For more options, visit https://groups.google.com/groups/opt_out.
