Class: Loom::Pattern::DefinitionContext

Inherits:
Object
  • Object
show all
Defined in:
lib/loom/pattern/definition_context.rb

Overview

Pattern::DefinitionContext is the collection of facts, hooks, and parent contexts a pattern is defined along side of. The context includes all contexts of parent modules.

Constant Summary collapse

NilLetValueError = 
Class.new Loom::LoomError

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(dsl_builder, parent_context = nil) ⇒ DefinitionContext

Returns a new instance of DefinitionContext.



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# File 'lib/loom/pattern/definition_context.rb', line 11

def initialize(dsl_builder, parent_context=nil)
  @fact_map = dsl_builder.facts.dup
  @let_map = dsl_builder.let_map.dup

  @hooks = dsl_builder.hooks.dup
  @parent_context = parent_context

  @merged_fact_map = merged_fact_map
  @merged_let_map = merged_let_map
end

Instance Attribute Details

#fact_map ⇒ Object (readonly)

Returns the value of attribute fact_map.



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# File 'lib/loom/pattern/definition_context.rb', line 22

def fact_map
  @fact_map
end

#hooks ⇒ Object (readonly)

Returns the value of attribute hooks.



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# File 'lib/loom/pattern/definition_context.rb', line 22

def hooks
  @hooks
end

#let_map ⇒ Object (readonly)

Returns the value of attribute let_map.



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# File 'lib/loom/pattern/definition_context.rb', line 22

def let_map
  @let_map
end

Instance Method Details

#after_hooks ⇒ Object 



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# File 'lib/loom/pattern/definition_context.rb', line 61

def after_hooks
  Hook.after_hooks merged_hooks.reverse
end

#before_hooks ⇒ Object 



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# File 'lib/loom/pattern/definition_context.rb', line 57

def before_hooks
  Hook.before_hooks merged_hooks
end

#define_let_readers(scope_object, fact_set) ⇒ Object

TODO: #define_let_readers is a TERRIBLE name. Rename this method. Also consider moving the instance_exec call to inside RunContext, it’s a bit misplaced here.

The method is called by Reference#call with the Reference::RunContext instance. The “let” defined local declarations are added as method definitions on each RunContext instance. The @merged_let_map is the map of let definitions, merged from the associated module, up the namespace graph, allowing for inheriting and overriding let declarations.



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# File 'lib/loom/pattern/definition_context.rb', line 40

def define_let_readers(scope_object, fact_set)
  @merged_let_map.each do |let_key, let_map_entry|
    Loom.log.debug { "evaluating let expression[:#{let_key}]" }
    value = scope_object.instance_exec fact_set, &let_map_entry.block
    value = value.nil? ? let_map_entry.default : value
    Loom.log.debug1(self) { "let[:#{let_key}] => #{value}" }

    if value.nil? || value.equal?(Loom::Facts::EMPTY)
      Loom.log.error "value of let expression[:#{let_key}] is nil"
      # TODO: I'm not sure what to do here, but raising an error isn't
      # very user friendly.... as I just learned.
#          raise NilLetValueError, "empty value for let[#{let_key}]"
    end
    scope_object.define_singleton_method(let_key) { value }
  end
end

#fact_set(host_fact_set) ⇒ Object

Merges the facts defined by the pattern context with the host fact_set



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# File 'lib/loom/pattern/definition_context.rb', line 27

def fact_set(host_fact_set)
  host_fact_set.merge merged_fact_map
end