stdlib 41.2.3

• Index

Contents

• Objects

Classes

• std.container
• std.list
• std.object
• std.optparse
• std.set
• std.strbuf
• std.tree

Modules

• std
• std.debug
• std.functional
• std.io
• std.math
• std.operator
• std.package
• std.strict
• std.string
• std.table

Class std.container

Container prototype.

A container is a std.object with no methods. It's functionality is instead defined by its *meta*methods.

Where an Object uses the `__index` metatable entry to hold object methods, a Container stores its contents using `__index`, preventing it from having methods in there too.

Although there are no actual methods, Containers are free to use metamethods (`__index`, `__sub`, etc) and, like Objects, can supply module functions by listing them in `_functions`. Also, since a std.container is a std.object, it can be passed to the std.object module functions, or anywhere else a std.object is expected.

When making your own prototypes, derive from std.container if you want to access the contents of your objects with the `[]` operator, or from std.object if you want to access the functionality of your objects with named object methods.

Prototype Chain ---------------

table `-> Object `-> Container

Objects

std.container.Container

Container prototype.

Objects

std.container.Container

Container prototype.

Container also inherits all the fields and methods from std.object.Object.

Fields:

• _type string object name (default "Container")

See also:

• std.object
• std.object.__call

Usage:

local std = require "std"
local Container = std.container {}

local Graph = Container {
  _type = "Graph",
  _functions = {
    nodes = function (graph)
      local n = 0
      for _ in std.pairs (graph) do n = n + 1 end
      return n
    end,
  },
}
local g = Graph { "node1", "node2" }
--> 2
print (Graph.nodes (g))