Module pl.Set
A Set class.
> Set = require 'pl.Set' > = Set{'one','two'} == Set{'two','one'} true > fruit = Set{'apple','banana','orange'} > = fruit['banana'] true > = fruit['hazelnut'] nil > colours = Set{'red','orange','green','blue'} > = fruit,colours [apple,orange,banana] [blue,green,orange,red] > = fruit+colours [blue,green,apple,red,orange,banana] [orange] > more_fruits = fruit + 'apricot' > = fruit*colours = more_fruits, fruit banana,apricot,apple,orange] [banana,apple,orange]
Dependencies: pl.utils, pl.tablex, pl.class, pl.Map, (pl.List if __tostring is used)
Functions
| Set (t) | create a set. | 
| values (self) | get a list of the values in a set. | 
| map (self, fn, ...) | map a function over the values of a set. | 
| union (self, set) | union of two sets (also +). | 
| intersection (self, set) | intersection of two sets (also *). | 
| difference (self, set) | new set with elements in the set that are not in the other (also -). | 
| issubset (self, set) | is the first set a subset of the second (also <)?. | 
| isempty (self) | is the set empty?. | 
| isdisjoint (s1, s2) | are the sets disjoint? | 
| len (s) | size of this set (also # for 5.2). | 
metamethods
| __tostring () | string representation of a set. | 
| __add () | union of sets. | 
| __mul () | intersection of sets. | 
| __sub () | difference of sets. | 
| __pow () | symmetric difference of sets. | 
| __lt () | first set subset of second? | 
| __len () | cardinality of set (5.2). | 
| __eq (s1, s2) | equality between sets. | 
Functions
- Set (t)
- 
    create a set.  
 Parameters:- t may be a Set, Map or list-like table.
 
- values (self)
- 
    get a list of the values in a set.
    Parameters:- self a Set
 Returns:- 
        a list
    
 
- map (self, fn, ...)
- 
    map a function over the values of a set.
    Parameters:- self a Set
- fn a function
- ... extra arguments to pass to the function.
 Returns:- 
        a new set
    
 
- union (self, set)
- 
    union of two sets (also +).
    Parameters:- self a Set
- set another set
 Returns:- 
        a new set
    
 
- intersection (self, set)
- 
    intersection of two sets (also *).
    Parameters:- self a Set
- set another set
 Returns:- 
        a new set
    
 Usage:> s = Set{10,20,30} > t = Set{20,30,40} > = t [20,30,40] > = Set.intersection(s,t) [30,20] > = s*t [30,20]
- difference (self, set)
- 
    new set with elements in the set that are not in the other (also -).
    Parameters:- self a Set
- set another set
 Returns:- 
        a new set
    
 
- issubset (self, set)
- 
    is the first set a subset of the second (also <)?.
    Parameters:- self a Set
- set another set
 Returns:- 
        true or false
    
 
- isempty (self)
- 
    is the set empty?.
    Parameters:- self a Set
 Returns:- 
        true or false
    
 
- isdisjoint (s1, s2)
- 
    are the sets disjoint?  (no elements in common).
 Uses naive definition, i.e. that intersection is empty
    Parameters:- s1 a Set
- s2 another set
 Returns:- 
        true or false
    
 
- len (s)
- 
    size of this set (also # for 5.2).
    Parameters:- s a Set
 Returns:- 
        size