Class: Toys::Utils::ModuleLookup

Inherits:
Object
  • Object
show all
Defined in:
lib/toys/utils/module_lookup.rb

Overview

A helper module that provides methods to do module lookups. This is used to obtain named helpers, middleware, and templates from the respective modules.

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize ⇒ ModuleLookup

Create an empty ModuleLookup



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# File 'lib/toys/utils/module_lookup.rb', line 86

def initialize
  @paths = []
end

Class Method Details

.path_to_module(path) ⇒ Module

Given a require path, return the module expected to be defined.

Parameters:

  • path (String) —

    File path, delimited by forward slash

Returns:

  • (Module) —

    The module loaded from that path



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# File 'lib/toys/utils/module_lookup.rb', line 72

def path_to_module(path)
  path.split("/").reduce(::Object) do |running_mod, seg|
    mod_name = to_module_name(seg)
    unless running_mod.constants.include?(mod_name)
      raise ::NameError, "Module #{running_mod.name}::#{mod_name} not found"
    end
    running_mod.const_get(mod_name)
  end
end

.to_module_name(str) ⇒ Symbol

Convert the given string to a module name. Specifically, converts to UpperCamelCase, and then to a symbol.

Parameters:

  • str (String, Symbol) —

    String to convert.

Returns:

  • (Symbol) —

    Converted name



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# File 'lib/toys/utils/module_lookup.rb', line 61

def to_module_name(str)
  str = str.to_s.sub(/^_/, "").sub(/_$/, "").gsub(/_+/, "_")
  str.to_s.gsub(/(^|_)([a-zA-Z])/) { |_m| $2.upcase }.to_sym
end

.to_path_name(str) ⇒ String

Convert the given string to a path element. Specifically, converts to lower_snake_case.

Parameters:

  • str (String, Symbol) —

    String to convert.

Returns:

  • (String) —

    Converted string



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# File 'lib/toys/utils/module_lookup.rb', line 48

def to_path_name(str)
  str = str.to_s.sub(/^_/, "").sub(/_$/, "").gsub(/_+/, "_")
  while str.sub!(/([^_])([A-Z])/, "\\1_\\2") do end
  str.downcase
end

Instance Method Details

#add_path(path_base, module_base: nil, high_priority: false) ⇒ Object

Add a lookup path for modules.

Parameters:

  • path_base (String) —

    The base require path

  • module_base (Module) (defaults to: nil) —

    The base module, or nil (the default) to infer a default from the path base.

  • high_priority (Boolean) (defaults to: false) —

    If true, add to the head of the lookup path, otherwise add to the end.



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# File 'lib/toys/utils/module_lookup.rb', line 99

def add_path(path_base, module_base: nil, high_priority: false)
  module_base ||= ModuleLookup.path_to_module(path_base)
  if high_priority
    @paths.unshift([path_base, module_base])
  else
    @paths << [path_base, module_base]
  end
  self
end

#lookup(name) ⇒ Module

Obtain a named module. Returns nil if the name is not present.

Parameters:

  • name (String, Symbol) —

    The name of the module to return.

Returns:

  • (Module) —

    The specified module



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# File 'lib/toys/utils/module_lookup.rb', line 116

def lookup(name)
  @paths.each do |path_base, module_base|
    path = "#{path_base}/#{ModuleLookup.to_path_name(name)}"
    begin
      require path
    rescue ::LoadError
      next
    end
    mod_name = ModuleLookup.to_module_name(name)
    unless module_base.constants.include?(mod_name)
      raise ::NameError,
            "File #{path.inspect} did not define #{module_base.name}::#{mod_name}"
    end
    return module_base.const_get(mod_name)
  end
  nil
end