Sets

Sets hold unique var values. Adding an element that is already present is a no-op, which makes sets handy for de-duplication and membership tests.

#include "abscom/abs.h"

Operations

Function	Description
var Set()	An empty set.
void set_add(var set_obj, var item)	Add an item (no-op if an equal item is already present).
bool set_contains(var set_obj, var item)	1 if the set contains an equal item, 0 otherwise.
var set_union(var a, var b)	New set with items from both.
var set_diff(var a, var b)	New set with items in a but not in b.

Example

abs_init();

var s = Set();
set_add(s, v(1));
set_add(s, v(2));
set_add(s, v(2));              /* no-op */

print(set_contains(s, v(1)));  /* True  */
print(set_contains(s, v(99))); /* False */
print(len(s));                 /* 2     */

var t = Set();
set_add(t, v(2));
set_add(t, v(3));

var u = set_union(s, t);       /* {1, 2, 3} */
var d = set_diff(s, t);        /* {1}       */

Equality semantics

set_contains follows the same rules as eq: numbers compare across int/float, so v(1) and v(1.0) match each other; strings compare by content.

Notes

• Iterate sets with foreach.
• Sets do not preserve insertion order.
• To add items, always use set_add — append only works on lists.

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