Set Operations Blueprint

Unordered collection of unique elements with set algebra operations (union, intersection, difference) and cardinality counting

Feature	set-operations
Category	Data
Version	1.0.0
Tags	sets, unordered-collections, set-algebra, cardinality
YAML Source	View on GitHub
JSON API	set-operations.json

Actors

ID	Name	Type	Description
client	Client	human	Application requesting set operations

Fields

Name	Type	Required	Label	Description
key	text	Yes
members	json	No
cardinality	number	No
destination_key	text	No

States

State field: undefined

Values:

| State | Initial | Terminal | |——-|———|———-|

Rules

• Set elements are unique; adding duplicate element replaces (no effect on cardinality)
• Set membership is unordered (no indices or ranges)
• Set algebra operations (intersection, union, difference) can accept multiple source sets
• Intersection of multiple sets returns elements present in ALL sets
• Union of multiple sets returns elements present in ANY set
• Difference of first set minus others returns elements in first but not in any other
• Store variants (*STORE) create destination set atomically; overwrite if exists
• All operations are atomic with respect to individual keys

Outcomes

Add_members (Priority: 10)

Given:

• SADD key member [member …]
• members_to_add (input) eq

Then:

• set_field target: members — add new members (duplicates ignored)
• set_field target: cardinality — increment by count of new members
• emit_event event: set.added

Result: set created if absent; members added; client receives count of newly added members

Remove_members (Priority: 11)

Given:

• SREM key member [member …]
• members_to_remove (input) eq

Then:

• set_field target: members — remove specified members
• set_field target: cardinality — decrement by count of removed members
• emit_event event: set.removed

Result: members removed; client receives count of removed members; set deleted if empty

Get_all_members (Priority: 20)

Given:

• SMEMBERS key

Then:

• emit_event event: set.members_read

Result: unordered array of all members (empty if set absent)

Check_membership (Priority: 21)

Given:

• SISMEMBER key member
• member (input) eq

Then:

• emit_event event: set.ismember_check

Result: 1 if member present, 0 if not

Check_multiple_membership (Priority: 22)

Given:

• SMISMEMBER key member [member …]
• members_to_check (input) eq

Then:

• emit_event event: set.mismember_check

Result: array of 0/1 for each member (1=member present, 0=absent)

Get_cardinality (Priority: 23)

Given:

• SCARD key

Then:

• emit_event event: set.cardinality

Result: number of members (0 if key absent)

Random_members (Priority: 24)

Given:

• SRANDMEMBER key [count]
• count (input) eq

Then:

• emit_event event: set.random_draw

Result: single member or array of members (may have duplicates if count > cardinality)

Pop_random (Priority: 25)

Given:

• SPOP key [count]
• count (input) eq

Then:

• set_field target: members — remove random members
• set_field target: cardinality — decrement by count removed
• emit_event event: set.popped

Result: single member or array of members removed (no duplicates); nil if empty

Move_between_sets (Priority: 26)

Given:

• SMOVE source destination member
• member_in_source (db) eq true

Then:

• set_field target: source.members — remove from source
• set_field target: destination.members — add to destination
• emit_event event: set.moved

Result: member moved; client receives 1 (or 0 if already in destination)

Intersection (Priority: 30)

Given:

• SINTER key [key …]
• input_sets (input) eq

Then:

• emit_event event: set.intersection

Result: array of elements in ALL sets (empty if no common elements)

Intersection_store (Priority: 31)

Given:

• SINTERSTORE destination key [key …]
• destination (input) eq

Then:

• set_field target: destination.members — set to intersection result
• emit_event event: set.intersection_stored

Result: destination set created/overwritten; client receives cardinality of result

Intersection_cardinality (Priority: 32)

Given:

• SINTERCARD numkeys key [key …] [LIMIT limit]
• limit (input) eq

Then:

• emit_event event: set.intercard

Result: cardinality of intersection (limited by LIMIT if provided)

Union (Priority: 33)

Given:

• SUNION key [key …]

Then:

• emit_event event: set.union

Result: array of unique elements across all sets

Union_store (Priority: 34)

Given:

• SUNIONSTORE destination key [key …]

Then:

• set_field target: destination.members — set to union result
• emit_event event: set.union_stored

Result: destination set created/overwritten; client receives cardinality

Difference (Priority: 35)

Given:

• SDIFF key [key …]
• first_key (input) eq
• other_keys (input) eq

Then:

• emit_event event: set.difference

Result: array of elements in first set minus all others

Difference_store (Priority: 36)

Given:

• SDIFFSTORE destination key [key …]

Then:

• set_field target: destination.members — set to difference result
• emit_event event: set.difference_stored

Result: destination set created/overwritten; client receives cardinality

Scan_members (Priority: 40)

Given:

• SSCAN key cursor [MATCH pattern] [COUNT count]
• cursor (input) eq

Then:

• emit_event event: set.scan

Result: array [new_cursor, [members…]] (cursor=0 when full scan complete)

Errors

Code	Status	Message	Retry
WRONG_TYPE		WRONGTYPE Operation against a key holding the wrong kind of value	No

Events

Event	Description	Payload
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Related Blueprints

Feature	Relationship	Reason
string-key-value	optional	Elements are strings or numeric values
sorted-set-operations	optional	Sorted sets extend sets with scoring

Extensions (framework-specific hints)

```yaml source: repo: https://github.com/redis/redis project: Redis tech_stack: C files_traced: 1 entry_points: - src/t_set.c ```