Class | Capsule |
In: |
lib/more/facets/capsule.rb
|
Parent: | Module |
A Capsule is subclass of Module. It encapsulates an extenal script as a funcitons module.
A module which is an instance of the Capsule class encapsulates in its scope the top-level methods, top-level constants, and instance variables defined in a ruby script file (and its subfiles) loaded by a ruby program. This allows use of script files to define objects that can be loaded into a program in much the same way that objects can be loaded from YAML or Marshal files.
See intro.txt for an overview.
load_path | [R] | An array of paths to search for scripts. This has the same semantics as $:, alias $LOAD_PATH, excpet that it is local to this script. The path of the current script is added automatically (equivalent to ’.’) |
loaded_features | [R] | A hash that maps filename=>true for each file that has been required locally by the script. This has the same semantics as $", alias $LOADED_FEATURES, except that it is local to this script. |
main_file | [R] | The script file with which the Import was instantiated. |
As with new but will search Ruby‘s $LOAD_PATH first.
# File lib/more/facets/capsule.rb, line 78 78: def load(main_file, options=nil, &block) 79: file = nil 80: $LOAD_PATH.each do |path| 81: break if file = File.file?(File.join(path, main_file)) 82: #break if file = Dir.glob(File.join(path, main_file)+'{,.rb,.'+DLEXT+'}')[0] 83: end 84: new(file || main_file, options=nil, &block) 85: end
Creates new Capsule, and loads main_file in the scope of the script. If a block is given, the script is passed to it before loading from the file, and constants can be defined as inputs to the script.
# File lib/more/facets/capsule.rb, line 92 92: def initialize(main_file, options=nil, &block) 93: extend self 94: 95: options ||= {} 96: 97: @main_file = File.expand_path(main_file) 98: @load_path = options[:load_path] || [] 99: #@load_path |= [File.dirname(@main_file)] # before or after? 100: @loaded_features = options[:loaded_features] || {} 101: 102: # TODO In order to load/require at the instance level. 103: # This needs to be in a separate namespace however 104: # b/c it can interfere with what is expected. 105: #[ :require, :load ].each{ |meth| 106: # m = method(meth) 107: # define_method(meth) do |*args| m.call(*args) end 108: #} 109: 110: module_eval(&block) if block 111: extend self 112: 113: load_in_module(main_file) 114: end
# File lib/more/facets/capsule.rb, line 204 204: def include(*mods) 205: super 206: extend self 207: end
# File lib/more/facets/capsule.rb, line 193 193: def include_script(file) 194: include self.class.new(file, :load_path=>load_path, :loaded_features=>loaded_features) 195: rescue Errno::ENOENT => e 196: if /#{file}$/ =~ e.message 197: raise MissingFile, e.message 198: else 199: raise 200: end 201: end
Loads file into the capsule. Searches relative to the local dir, that is, the dir of the file given in the original call to Capsule.load(file), loads the file, if found, into this Capsule‘s scope, and returns true. If the file is not found, falls back to Kernel.load, which searches on $LOAD_PATH, loads the file, if found, into global scope, and returns true. Otherwise, raises LoadError.
The wrap argument is passed to Kernel.load in the fallback case, when the file is not found locally.
Typically called from within the main file to load additional sub files, or from those sub files.
# File lib/more/facets/capsule.rb, line 143 143: def load(file, wrap = false) 144: load_in_module(File.join(@dir, file)) 145: true 146: rescue MissingFile 147: super 148: end
Loads file in this module‘s context. Note that __FILE__ and __LINE__ work correctly in file. Called by load and require; not normally called directly.
# File lib/more/facets/capsule.rb, line 183 183: def load_in_module(file) 184: module_eval(IO.read(file), File.expand_path(file)) 185: rescue Errno::ENOENT => e 186: if /#{file}$/ =~ e.message 187: raise MissingFile, e.message 188: else 189: raise 190: end 191: end
Lookup feature in load path.
# File lib/more/facets/capsule.rb, line 118 118: def load_path_lookup(feature) 119: paths = File.join('{' + @load_path.join(',') + '}', feature + '{,.rb,.rbs}') 120: files = Dir.glob(paths) 121: match = files.find{ |f| ! @loaded_features.include?(f) } 122: return match 123: end
Analogous to Kernel#require. First tries the local dir, then falls back to Kernel#require. Will load a given feature only once.
Note that extensions (*.so, *.dll) can be required in the global scope, as usual, but not in the local scope. (This is not much of a limitation in practice—you wouldn‘t want to load an extension more than once.) This implementation falls back to Kernel#require when the argument is an extension or is not found locally.
# File lib/more/facets/capsule.rb, line 164 164: def require(feature) 165: file = load_path_lookup(feature) 166: return super unless file 167: begin 168: @loaded_features[file] = true 169: load_in_module(file) 170: rescue MissingFile 171: @loaded_features[file] = false 172: super 173: end 174: end