Class Haml::Util::SubsetMap
In: lib/haml/util/subset_map.rb
Parent: Object

A map from sets to values. A value is \{#\[]= set} by providing a set (the "set-set") and a value, which is then recorded as corresponding to that set. Values are \{#\[] accessed} by providing a set (the "get-set") and returning all values that correspond to set-sets that are subsets of the get-set.

SubsetMap preserves the order of values as they‘re inserted.

@example ssm = SubsetMap.new ssm[Set[1, 2]] = "Foo" ssm[Set[2, 3]] = "Bar" ssm[Set[1, 2, 3]] = "Baz"

ssm[Set[1, 2, 3]] #=> ["Foo", "Bar", "Baz"]

Methods

[]   []=   empty?   get   new  

Public Class methods

Creates a new, empty SubsetMap.

Public Instance methods

Same as \{get}, but doesn‘t return the subsets of the argument for which values were found.

@param set [Set] The set to use as the map key. @return [Array] The array of all values

  associated with subsets of `set`, in insertion order.

@see get

Associates a value with a set. When `set` or any of its supersets is accessed, `value` will be among the values returned.

Note that if the same `set` is passed to this method multiple times, all given `value`s will be associated with that `set`.

This runs in `O(n)` time, where `n` is the size of `set`.

@param set [to_set] The set to use as the map key. May not be empty. @param value [Object] The value to associate with `set`. @raise [ArgumentError] If `set` is empty.

Whether or not this SubsetMap has any key-value pairs.

@return [Boolean]

Returns all values associated with subsets of `set`.

In the worst case, this runs in `O(m*max(n, log m))` time, where `n` is the size of `set` and `m` is the number of assocations in the map. However, unless many keys in the map overlap with `set`, `m` will typically be much smaller.

@param set [Set] The set to use as the map key. @return [Array<(Object, to_set)>] An array of pairs,

  where the first value is the value associated with a subset of `set`,
  and the second value is that subset of `set`
  (or whatever `#to_set` object was used to set the value)
  This array is in insertion order.

@see #[]

[Validate]