object

`redis`

Redis client library with support for strings, keys, hashes, lists, sets, and sorted sets. Inspired by Sean Charles GNU Prolog Redis client.

Availability:

logtalk_load(redis(loader))

Author: Paulo Moura
Version: 0:7:0
Date: 2026-02-10

Compilation flags:

static, context_switching_calls

Provides:

logtalk::message_tokens//2

Uses:

list
logtalk
socket

Remarks:

Command representation: Use the Redis command name as the functor of a compound term where the arguments are the command arguments.

Valid arguments: Atoms, integers, and floats. Always use atoms instead of double-quoted “strings”. This helps portability by not depending on the value of the double_quotes flag.

Wrapper predicates: The library provides convenient wrapper predicates for common Redis operations. For operations without a wrapper, use the generic send/3 predicate.

Inherited public predicates:

(none)

Public predicates 

`connect/1`

Connect to a Redis server running on localhost using the default 6379 port.

Compilation flags:

static

Template:

connect(Connection)

Mode and number of proofs:

connect(--ground) - one

`connect/3`

Connect to a Redis server running on the given host and port.

Compilation flags:

static

Template:

connect(Host,Port,Connection)

Mode and number of proofs:

connect(+atom,+integer,--ground) - one

`disconnect/1`

Disconnect from a Redis server.

Compilation flags:

static

Template:

disconnect(Connection)

Mode and number of proofs:

disconnect(++ground) - one

`send/3`

Sends a request to the a Redis server and returns its reply.

Compilation flags:

static

Template:

send(Connection,Request,Reply)

Mode and number of proofs:

send(++ground,++callable,--callable) - one

`console/1`

Sends a request to a Redis server running on localhost at the default 6379 port and prints the reply.

Compilation flags:

static

Template:

console(Request)

Mode and number of proofs:

console(++callable) - one

`get/3`

Gets the value of a key.

Compilation flags:

static

Template:

get(Connection,Key,Value)

Mode and number of proofs:

get(+ground,+atom,-atom) - one

`set/4`

Sets the value of a key.

Compilation flags:

static

Template:

set(Connection,Key,Value,Status)

Mode and number of proofs:

set(+ground,+atom,+ground,-atom) - one

`append/4`

Appends a value to a key. Returns the length of the string after the append.

Compilation flags:

static

Template:

append(Connection,Key,Value,Length)

Mode and number of proofs:

append(+ground,+atom,+ground,-integer) - one

`getrange/5`

Gets a substring of the string stored at a key.

Compilation flags:

static

Template:

getrange(Connection,Key,Start,End,Substring)

Mode and number of proofs:

getrange(+ground,+atom,+integer,+integer,-atom) - one

`setrange/5`

Overwrites part of a string at a key starting at the specified offset. Returns the length of the string after modification.

Compilation flags:

static

Template:

setrange(Connection,Key,Offset,Value,Length)

Mode and number of proofs:

setrange(+ground,+atom,+integer,+ground,-integer) - one

`strlen/3`

Gets the length of the value stored at a key.

Compilation flags:

static

Template:

strlen(Connection,Key,Length)

Mode and number of proofs:

strlen(+ground,+atom,-integer) - one

`mget/3`

Gets the values of multiple keys. Returns a list of values.

Compilation flags:

static

Template:

mget(Connection,Keys,Values)

Mode and number of proofs:

mget(+ground,+list(atom),-list) - one

`mset/3`

Sets multiple key-value pairs. Pairs should be provided as a flat list [Key1, Value1, Key2, Value2, …].

Compilation flags:

static

Template:

mset(Connection,Pairs,Status)

Mode and number of proofs:

mset(+ground,+list,-atom) - one

`incr/3`

Increments the integer value of a key by one. Returns the value after increment.

Compilation flags:

static

Template:

incr(Connection,Key,Value)

Mode and number of proofs:

incr(+ground,+atom,-integer) - one

`decr/3`

Decrements the integer value of a key by one. Returns the value after decrement.

Compilation flags:

static

Template:

decr(Connection,Key,Value)

Mode and number of proofs:

decr(+ground,+atom,-integer) - one

`incrby/4`

Increments the integer value of a key by the specified amount. Returns the value after increment.

Compilation flags:

static

Template:

incrby(Connection,Key,Increment,Value)

Mode and number of proofs:

incrby(+ground,+atom,+integer,-integer) - one

`decrby/4`

Decrements the integer value of a key by the specified amount. Returns the value after decrement.

Compilation flags:

static

Template:

decrby(Connection,Key,Decrement,Value)

Mode and number of proofs:

decrby(+ground,+atom,+integer,-integer) - one

`del/3`

Deletes a key. Returns the number of keys removed.

Compilation flags:

static

Template:

del(Connection,Key,Count)

Mode and number of proofs:

del(+ground,+atom,-integer) - one

`exists/3`

Checks if a key exists. Returns 1 if the key exists, 0 otherwise.

Compilation flags:

static

Template:

exists(Connection,Key,Exists)

Mode and number of proofs:

exists(+ground,+atom,-integer) - one

`keys/3`

Finds all keys matching a pattern. Returns a list of keys.

Compilation flags:

static

Template:

keys(Connection,Pattern,Keys)

Mode and number of proofs:

keys(+ground,+atom,-list) - one

`ttl/3`

Gets the time to live for a key in seconds. Returns -1 if the key has no expiry, -2 if the key does not exist.

Compilation flags:

static

Template:

ttl(Connection,Key,Seconds)

Mode and number of proofs:

ttl(+ground,+atom,-integer) - one

`expire/4`

Sets a timeout on a key in seconds. Returns 1 if the timeout was set, 0 if the key does not exist.

Compilation flags:

static

Template:

expire(Connection,Key,Seconds,Result)

Mode and number of proofs:

expire(+ground,+atom,+integer,-integer) - one

`persist/3`

Removes the expiration from a key. Returns 1 if the timeout was removed, 0 if the key does not exist or has no timeout.

Compilation flags:

static

Template:

persist(Connection,Key,Result)

Mode and number of proofs:

persist(+ground,+atom,-integer) - one

`rename/4`

Renames a key. Returns status OK or error if the key does not exist.

Compilation flags:

static

Template:

rename(Connection,OldKey,NewKey,Status)

Mode and number of proofs:

rename(+ground,+atom,+atom,-atom) - one

`type/3`

Gets the type of the value stored at a key. Returns one of: string, list, set, zset, hash, stream, none.

Compilation flags:

static

Template:

type(Connection,Key,Type)

Mode and number of proofs:

type(+ground,+atom,-atom) - one

`hset/5`

Sets a field in a hash. Returns 1 if a new field was created, 0 if the field was updated.

Compilation flags:

static

Template:

hset(Connection,Key,Field,Value,Result)

Mode and number of proofs:

hset(+ground,+atom,+atom,+ground,-integer) - one

`hget/4`

Gets the value of a field in a hash.

Compilation flags:

static

Template:

hget(Connection,Key,Field,Value)

Mode and number of proofs:

hget(+ground,+atom,+atom,-ground) - one

`hgetall/3`

Gets all fields and values in a hash. Returns a flat list of alternating fields and values.

Compilation flags:

static

Template:

hgetall(Connection,Key,FieldsValues)

Mode and number of proofs:

hgetall(+ground,+atom,-list) - one

`hdel/4`

Deletes a field from a hash. Returns the number of fields removed.

Compilation flags:

static

Template:

hdel(Connection,Key,Field,Count)

Mode and number of proofs:

hdel(+ground,+atom,+atom,-integer) - one

`hexists/4`

Checks if a field exists in a hash. Returns 1 if the field exists, 0 otherwise.

Compilation flags:

static

Template:

hexists(Connection,Key,Field,Exists)

Mode and number of proofs:

hexists(+ground,+atom,+atom,-integer) - one

`hkeys/3`

Gets all field names in a hash.

Compilation flags:

static

Template:

hkeys(Connection,Key,Fields)

Mode and number of proofs:

hkeys(+ground,+atom,-list) - one

`hvals/3`

Gets all values in a hash.

Compilation flags:

static

Template:

hvals(Connection,Key,Values)

Mode and number of proofs:

hvals(+ground,+atom,-list) - one

`hlen/3`

Gets the number of fields in a hash.

Compilation flags:

static

Template:

hlen(Connection,Key,Count)

Mode and number of proofs:

hlen(+ground,+atom,-integer) - one

`lpush/4`

Prepends a value to a list. Returns the length of the list after the push.

Compilation flags:

static

Template:

lpush(Connection,Key,Value,Length)

Mode and number of proofs:

lpush(+ground,+atom,+ground,-integer) - one

`rpush/4`

Appends a value to a list. Returns the length of the list after the push.

Compilation flags:

static

Template:

rpush(Connection,Key,Value,Length)

Mode and number of proofs:

rpush(+ground,+atom,+ground,-integer) - one

`lpop/3`

Removes and returns the first element of a list.

Compilation flags:

static

Template:

lpop(Connection,Key,Value)

Mode and number of proofs:

lpop(+ground,+atom,-ground) - one

`rpop/3`

Removes and returns the last element of a list.

Compilation flags:

static

Template:

rpop(Connection,Key,Value)

Mode and number of proofs:

rpop(+ground,+atom,-ground) - one

`lrange/5`

Gets a range of elements from a list. Indices are zero-based.

Compilation flags:

static

Template:

lrange(Connection,Key,Start,Stop,Elements)

Mode and number of proofs:

lrange(+ground,+atom,+integer,+integer,-list) - one

`llen/3`

Gets the length of a list.

Compilation flags:

static

Template:

llen(Connection,Key,Length)

Mode and number of proofs:

llen(+ground,+atom,-integer) - one

`lrem/5`

Removes elements from a list. Count > 0: remove from head, Count < 0: remove from tail, Count = 0: remove all. Returns the number of removed elements.

Compilation flags:

static

Template:

lrem(Connection,Key,Count,Value,Removed)

Mode and number of proofs:

lrem(+ground,+atom,+integer,+ground,-integer) - one

`ltrim/5`

Trims a list to the specified range.

Compilation flags:

static

Template:

ltrim(Connection,Key,Start,Stop,Status)

Mode and number of proofs:

ltrim(+ground,+atom,+integer,+integer,-atom) - one

`sadd/4`

Adds a member to a set. Returns the number of elements added.

Compilation flags:

static

Template:

sadd(Connection,Key,Member,Count)

Mode and number of proofs:

sadd(+ground,+atom,+ground,-integer) - one

`srem/4`

Removes a member from a set. Returns the number of elements removed.

Compilation flags:

static

Template:

srem(Connection,Key,Member,Count)

Mode and number of proofs:

srem(+ground,+atom,+ground,-integer) - one

`smembers/3`

Gets all members in a set.

Compilation flags:

static

Template:

smembers(Connection,Key,Members)

Mode and number of proofs:

smembers(+ground,+atom,-list) - one

`sismember/4`

Checks if a value is a member of a set. Returns 1 if the member exists, 0 otherwise.

Compilation flags:

static

Template:

sismember(Connection,Key,Member,IsMember)

Mode and number of proofs:

sismember(+ground,+atom,+ground,-integer) - one

`scard/3`

Gets the number of members in a set.

Compilation flags:

static

Template:

scard(Connection,Key,Count)

Mode and number of proofs:

scard(+ground,+atom,-integer) - one

`zadd/5`

Adds a member with a score to a sorted set. Returns the number of elements added.

Compilation flags:

static

Template:

zadd(Connection,Key,Score,Member,Count)

Mode and number of proofs:

zadd(+ground,+atom,+number,+ground,-integer) - one

`zrem/4`

Removes a member from a sorted set. Returns the number of elements removed.

Compilation flags:

static

Template:

zrem(Connection,Key,Member,Count)

Mode and number of proofs:

zrem(+ground,+atom,+ground,-integer) - one

`zrange/5`

Gets a range of members from a sorted set, ordered from lowest to highest score.

Compilation flags:

static

Template:

zrange(Connection,Key,Start,Stop,Members)

Mode and number of proofs:

zrange(+ground,+atom,+integer,+integer,-list) - one

`zrank/4`

Gets the rank (index) of a member in a sorted set, ordered from lowest to highest score. Returns nil if the member does not exist.

Compilation flags:

static

Template:

zrank(Connection,Key,Member,Rank)

Mode and number of proofs:

zrank(+ground,+atom,+ground,-integer) - one

`zcard/3`

Gets the number of members in a sorted set.

Compilation flags:

static

Template:

zcard(Connection,Key,Count)

Mode and number of proofs:

zcard(+ground,+atom,-integer) - one

`zscore/4`

Gets the score of a member in a sorted set.

Compilation flags:

static

Template:

zscore(Connection,Key,Member,Score)

Mode and number of proofs:

zscore(+ground,+atom,+ground,-ground) - one

redis

`redis`