stdlib 41.2.2 Reference

# Class `std.container`

Container prototype.

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

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))

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