Module: SwarmSDK::ProcHelpers

Defined in:
lib/swarm_sdk/proc_helpers.rb

Overview

Helper methods for working with Procs and Lambdas

Provides functionality to convert regular Proc objects into Lambdas to enable safe use of return statements in DSL blocks (like input/output transformers).

Class Method Summary collapse

Class Method Details

.to_lambda(proc) ⇒ Proc

Convert a Proc to a Lambda

The fundamental difference between a Proc and a Lambda is in how they handle return statements. In a Proc, return exits the enclosing method (or program), while in a Lambda, return only exits the lambda itself.

This method converts a Proc to a Lambda by:

  1. Converting the proc to an unbound method via define_method
  2. Wrapping it in a lambda that binds and calls the method
  3. In the method, return exits the method (not the original scope)

This allows users to write natural control flow with return statements:

Examples:

my_proc = proc { |x| return x * 2 if x > 0; 0 }
my_lambda = ProcHelpers.to_lambda(my_proc)
my_lambda.call(5)  # => 10 (return works safely!)



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# File 'lib/swarm_sdk/proc_helpers.rb', line 30

def to_lambda(proc)
  return proc if proc.lambda?

  # Save local reference to proc so we can use it in module_exec/lambda scopes
  source_proc = proc

  # Convert proc to unbound method
  # define_method with a block converts the block to a method, where return
  # exits the method (not the original scope)
  unbound_method = Module.new.module_exec do
    instance_method(define_method(:_proc_call, &source_proc))
  end

  # Return lambda which binds our unbound method to correct receiver and calls it
  lambda do |*args, **kwargs, &block|
    # Bind method to the original proc's receiver (the context where it was defined)
    # This preserves access to instance variables, local variables via closure, etc.
    receiver = source_proc.binding.eval("self")
    unbound_method.bind(receiver).call(*args, **kwargs, &block)
  end
end