# Procer **NOTE: Experimental. Use it to experience what a default `to_proc` could have been. For production code, I recommend an explicit transformation, like the one provided by the gem `jgomo3-func`**. A reasonable good default `to_proc` method for all objects. Install with: ``` gem install procer ``` When you require Procer, all objects will have a default `to_proc` method which will try to call one of the following methods, in the given order: - `call` - `[]` - `===` Many methods which receive a block, can benefit greatly from this because you can now pass an object to perform the block role. Think of the Enumerable module and all its methods. Many objects define `===`, but not `to_proc`. So they will be nicely usable in a `case/when` expression, but not in other contexts. This is the case of classes and ranges, which you can use in `case/when` expressions, but they don't define `to_proc`. Now they do define `to_proc` so they are useful in those contexts. Examples: ```ruby require 'procer' [1, 2, '3', '4', 5, 6].filter(&Numeric) # => [1, 2, 5, 6] [-10, 100, -2, 3, 20, -33].filter(&(0..50)) # => [3, 20] ``` Also, Hashes already implement `to_proc` and that is useful with Enumerator. We can use it as a transformation table with `map`: ```ruby table = { 1 => 'one', 2 => 'two', 3 => 'three' } [3, 1, 2].map(&table) # => ['three, 'one, 'two'] ``` Sadly, Arrays, even when they have the same interface as hashes as a function of indices, don't implement `to_proc` and so they can't be used in the same way. Until now. ```ruby table = ['zero', 'one', 'two'] [2, 0, 1].map(&table) # => ['two', 'zero', 'one'] ``` Alternatively, you could have used `values_at`: ```ruby table.values_at([3, 1, 2]) # In the Hash example table.values_at([2, 0, 1]) # In the Array example ``` But the map solution is more generic and `table` can be anything that implements `to_proc` and not something that necessarily implements `values_at`. Notice that if the object implements `[]` that will triumph over `===`. It was unexpected when I tried to use Integers as the object, as they implement `[]` as a way to access their binary form: ```ruby 5 # b101 [5[2], 5[1], 5[0]] # [1, 0, 1] ``` So the proc will work like that: ```ruby [2, 4, 5].map(&5) # Actual => [1, 0, 0] # I was expecting => [false, false, true] ```