module Sequel::Plugins

Empty namespace that plugins should use to store themselves, so they can be loaded via Model.plugin.

Plugins should be modules with one of the following conditions:

Constants

SEQUEL_METHOD_NAME

Return a unique method name symbol for the given suffix.

Public Class Methods

after_set_dataset(mod, meth) click to toggle source

Add method to mod that overrides set_dataset to call the method afterward.

Calls superclass method
   # File lib/sequel/model/plugins.rb
46 def self.after_set_dataset(mod, meth)
47   mod.send(:define_method, :set_dataset) do |*a|
48     r = super(*a)
49     # Allow calling private class methods as methods this specifies are usually private
50     send(meth)
51     r
52   end
53 end
def_dataset_methods(mod, meths) click to toggle source

In the given module mod, define methods that are call the same method on the dataset. This is designed for plugins to define dataset methods inside ClassMethods that call the implementations in DatasetMethods.

This should not be called with untrusted input or method names that can't be used literally, since it uses class_eval.

   # File lib/sequel/model/plugins.rb
31 def self.def_dataset_methods(mod, meths)
32   Array(meths).each do |meth|
33     mod.class_eval("def #{meth}(*args, &block); dataset.#{meth}(*args, &block) end", __FILE__, __LINE__)
34   end
35 end
def_sequel_method(model, meth, expected_arity, &block) click to toggle source

Define a private instance method using the block with the provided name and expected arity. If the name is given as a Symbol, it is used directly. If the name is given as a String, a unique name will be generated using that string. The expected_arity should be either 0 (no arguments) or 1 (single argument).

If a block with an arity that does not match the expected arity is used, a deprecation warning will be issued. The method defined should still work, though it will be slower than a method with the expected arity.

Sequel only checks arity for regular blocks, not lambdas. Lambdas were already strict in regards to arity, so there is no need to try to fix arity to keep backwards compatibility for lambdas.

Blocks with required keyword arguments are not supported by this method.

    # File lib/sequel/model/plugins.rb
 77 def self.def_sequel_method(model, meth, expected_arity, &block)
 78   if meth.is_a?(String)
 79     meth = SEQUEL_METHOD_NAME.call(meth)
 80   end
 81   call_meth = meth
 82 
 83   unless block.lambda?
 84     required_args, optional_args, rest, keyword = _define_sequel_method_arg_numbers(block)
 85 
 86     if keyword == :required
 87       raise Error, "cannot use block with required keyword arguments when calling define_sequel_method with expected arity #{expected_arity}"
 88     end
 89 
 90     case expected_arity
 91     when 0
 92       unless required_args == 0
 93         # SEQUEL6: remove
 94         Sequel::Deprecation.deprecate("Arity mismatch in block passed to define_sequel_method. Expected Arity 0, but arguments required for #{block.inspect}. Support for this will be removed in Sequel 6.")
 95         b = block
 96         block = lambda{instance_exec(&b)} # Fallback
 97       end
 98     when 1
 99       if required_args == 0 && optional_args == 0 && !rest
100         # SEQUEL6: remove
101         Sequel::Deprecation.deprecate("Arity mismatch in block passed to define_sequel_method. Expected Arity 1, but no arguments accepted for #{block.inspect}.  Support for this will be removed in Sequel 6.")
102         temp_method = SEQUEL_METHOD_NAME.call("temp")
103         model.class_eval("def #{temp_method}(_) #{meth =~ /\A\w+\z/ ? "#{meth}_arity" : "send(:\"#{meth}_arity\")"} end", __FILE__, __LINE__)
104         model.send(:alias_method, meth, temp_method)
105         model.send(:undef_method, temp_method)
106         model.send(:private, meth)
107         meth = :"#{meth}_arity"
108       elsif required_args > 1
109         # SEQUEL6: remove
110         Sequel::Deprecation.deprecate("Arity mismatch in block passed to define_sequel_method. Expected Arity 1, but more arguments required for #{block.inspect}.  Support for this will be removed in Sequel 6.")
111         b = block
112         block = lambda{|r| instance_exec(r, &b)} # Fallback
113       end
114     else
115       raise Error, "unexpected arity passed to define_sequel_method: #{expected_arity.inspect}"
116     end
117   end
118 
119   model.send(:define_method, meth, &block)
120   model.send(:private, meth)
121   call_meth
122 end
inherited_instance_variables(mod, hash) click to toggle source

Add method to mod that overrides inherited_instance_variables to include the values in this hash.

Calls superclass method
   # File lib/sequel/model/plugins.rb
39 def self.inherited_instance_variables(mod, hash)
40   mod.send(:define_method, :inherited_instance_variables) do ||
41     super().merge!(hash)
42   end
43 end

Private Class Methods

_define_sequel_method_arg_numbers(callable) click to toggle source

Return the number of required argument, optional arguments, whether the callable accepts any additional arguments, and whether the callable accepts keyword arguments (true, false or :required).

    # File lib/sequel/model/plugins.rb
128 def self._define_sequel_method_arg_numbers(callable)
129   optional_args = 0
130   rest = false
131   keyword = false
132   callable.parameters.map(&:first).each do |arg_type, _|
133     case arg_type
134     when :opt
135       optional_args += 1
136     when :rest
137       rest = true
138     when :keyreq
139       keyword = :required
140     when :key, :keyrest
141       keyword ||= true
142     end
143   end
144   arity = callable.arity
145   if arity < 0
146     arity = arity.abs - 1
147   end
148   required_args = arity
149   arity -= 1 if keyword == :required
150 
151   if callable.is_a?(Proc) && !callable.lambda?
152     optional_args -= arity
153   end
154 
155   [required_args, optional_args, rest, keyword]
156 end