The agent Lib — Native Actor Concurrency (agent, send, receive), KV Store, and Rate Limiter

38.1. Why Does the agent Lib Exist? (The Real-World Problem & Ridgun Philosophy)

"Why do I need a agent lib written from scratch in pure Ridgun instead of just linking a legacy C library?"

That is the first question every systems engineer asks when meeting agent. And the answer captures the entire philosophy of ridgun-libs:

Let's be honest: sharing mutable state across threads with Mutex, RwLock, and condition variables is an endless factory of deadlocks and race conditions.

The agent lib builds on Ridgun's Native Agent Model (agent, send ... to, receive from, try receive from, stop) to provide isolated message-passing actors, a concurrent key-value store (KvStore), a token-bucket rate limiter (RateBucket), and supervision state machines (AgentHealth).

In a traditional ecosystem, solving AGENT tasks means pulling in external C dependencies, wrestling with raw pointers, opaque type conversions, unchecked exceptions, or unpredictable garbage-collector pauses. In Ridgun, the agent lib (src/main/ridgun/lib/agent.rg) tackles the problem with four non-negotiable principles:

1. Declare import agent (or import agent as alias) at the top of your file: every lib defines its module :: agent namespace, and under --strict multi-word functions are always called with natural spaces.
2. Chain your data pipelines left-to-right with ->: write input step one -> step two -> result, use (+ _ _ +) sequence masks to destructure tuples/lists, and omit _ = on sequential statements (or discard with -> ()).
3. Tail-Call Optimization (TCO): all internal loops in agent are tail-recursive and compile into native hardware loops using $O(1)$ stack space.
4. Deterministic Memory (RMM1 / RMM2): every intermediate allocation is reclaimed at the exact instruction where its last read finishes, with no Garbage Collector.

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38.2. Native Artifacts, Imports, and Complete agent API Catalog

In ridgun-libs, agent is a first-class lib located at src/main/ridgun/lib/agent.rg (domain AGENT). When built with stable bundle, it compiles into three native artifacts:

Artifact	Path	Purpose
Ridgun Bundle	target/bundles/agent.rglib	Portable distribution and direct import agent resolution
Compiled Archive	target/agent.rgc	Type-checked intermediate artifact verified by ridgunc
ELF64 Shared Object	target/libagent.so	Native dynamic shared library with zero C or libc dependencies

Every lib declares its own namespace via module :: agent: simply write import agent (or import agent as alias) at the top and call its functions with natural spaces (my fn x) and left-to-right -> pipelines (x my fn -> result).

38.2.1. Summary of agent Functional Families

Signature / Function / Type	Purpose & Usage
agent roundtrip / agent drain count	Spawn native Ridgun actors (agent), exchange messages (send ... to / receive from), and stop cleanly
kv store new / kv store apply	Actor-ready immutable key-value store (KvPut, KvGet, KvDelete, KvClear)
rate bucket new / rate bucket allow	Token-bucket rate limiter returning updated bucket and (allowed, remaining)
sup mark failed / sup should restart	Supervision policy helpers tracking restart budgets (max_restarts)

38.2.2. Exhaustive Catalog of Types and Signatures in src/main/ridgun/lib/agent.rg

Below is the complete inventory of algebraic data types (type), mixfix operators (op ::), and function signatures (fn ::) defined in src/main/ridgun/lib/agent.rg (7 types, 0 operators, and 65 functions):

Algebraic Data Types & Records (type) in agent:

type AgentStatus = AgentRunning | AgentStopped | AgentTimedOut Int | AgentFailed String
type AgentReply  = ReplyInt Int | ReplyStr String | ReplyBool Bool | ReplyEmpty | ReplyStopped | ReplyTimeout Int | ReplyError String
type CounterState = cnt_val: Int
type KvCmd        = KvPut String String | KvGet String | KvDel String | KvHas String | KvCount | KvKeys | KvClear
type KvEntry      = kv_k: String, kv_v: String
type KvState      = kv_size: Int, kv_items: [KvEntry]
type LogState     = log_sep: String, log_buf: String

#	Function / Signature (fn ::)	Return Type
1	fn :: format agent status AgentStatus	String
2	fn :: format agent reply AgentReply	String
3	fn :: is agent alive (Agent A B)	Bool
4	fn :: agent status (Agent A B)	AgentStatus
5	fn :: stop agent (Agent A B)	AgentStatus
6	fn :: agent stop all [Agent]	()
7	fn :: agent ask Agent A	B
8	fn :: agent try ask Agent A	Option
9	fn :: agent send batch Agent [A]	()
10	fn :: agent receive count Agent Int	[B]
11	fn :: agent receive count loop Agent Int [B]	[B]
12	fn :: agent map batch Agent [A]	[B]
13	fn :: agent list len [A] Int	Int
14	fn :: agent drain ready Agent	[B]
15	fn :: agent drain ready loop Agent [B]	[B]
16	fn :: agent drain step Agent Option [B]	[B]
17	fn :: ag cast opt A	B
18	fn :: ag unwrap try int (Option Int)	AgentReply
19	fn :: ag unwrap try str (Option String)	AgentReply
20	fn :: ask int (Agent Int Int) Int	AgentReply
21	fn :: ask str (Agent String String) String	AgentReply
22	fn :: try poll int (Agent A Int)	AgentReply
23	fn :: try poll str (Agent A String)	AgentReply
24	fn :: ag poll int step (Agent Int Int) (Option Int) Int Int	AgentReply
25	fn :: ag wait int loop (Agent Int Int) Int Int	AgentReply
26	fn :: ask int with timeout (Agent Int Int) Int Int	AgentReply
27	fn :: ag poll str step (Agent String String) (Option String) Int Int	AgentReply
28	fn :: ag wait str loop (Agent String String) Int Int	AgentReply
29	fn :: ask str with timeout (Agent String String) String Int	AgentReply
30	fn :: ask batch int (Agent Int Int) [Int]	[Int]
31	fn :: ask batch str (Agent String String) [String]	[String]
32	fn :: relay int (Agent Int Int) (Agent Int Int) Int	AgentReply
33	fn :: relay str (Agent String String) (Agent String String) String	AgentReply
34	fn :: ag counter step CounterState Int	CounterState Int
35	fn :: new counter agent Int	Agent Int Int
36	fn :: counter add (Agent Int Int) Int	Int
37	fn :: counter get (Agent Int Int)	Int
38	fn :: counter reset (Agent Int Int)	Int
39	fn :: ag log join String String String	String
40	fn :: ag log step LogState String	LogState String
41	fn :: new log agent String	Agent String String
42	fn :: log append (Agent String String) String	String
43	fn :: log read (Agent String String)	String
44	fn :: log clear (Agent String String)	String
45	fn :: ag kv lookup [KvEntry] String	String
46	fn :: ag kv exists [KvEntry] String	Bool
47	fn :: ag kv put list [KvEntry] String String	[KvEntry]
48	fn :: ag kv del list [KvEntry] String	[KvEntry]
49	fn :: ag kv len [KvEntry]	Int
50	fn :: ag kv keys join String String	String
51	fn :: ag kv keys str [KvEntry]	String
52	fn :: ag kv has str Bool	String
53	fn :: ag kv next state KvState KvCmd	KvState
54	fn :: ag kv next reply KvState KvCmd	String
55	fn :: ag kv step KvState KvCmd	KvState String
56	fn :: new kv agent	Agent KvCmd String
57	fn :: ag kv call (Agent KvCmd String) KvCmd	String
58	fn :: kv put (Agent KvCmd String) String String	String
59	fn :: kv get (Agent KvCmd String) String	String
60	fn :: kv delete (Agent KvCmd String) String	String
61	fn :: kv has (Agent KvCmd String) String	Bool
62	fn :: ag parse int String	Int
63	fn :: kv count (Agent KvCmd String)	Int
64	fn :: kv keys (Agent KvCmd String)	String
65	fn :: kv clear (Agent KvCmd String)	String

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38.3. Deep Dive into agent: Step-by-Step Examples for Every Feature

A signature table alone is never enough: let's explore every capability of the agent lib through progressive, runnable Ridgun examples. We will start with two everyday tabular recipes and then walk through every functional scenario, transformation, and boundary condition verified in src/test/ridgun/test agent.rg.

38.3.1. Example 1: Core Tabular Workflow with agent

Notice how in Ridgun the = signs and transformation steps using agent align into a clean, scannable table without unnecessary mutable variables or hidden side effects:

import agent

fn :: probar contador actor => Int Int
      probar contador actor =
        10 new counter agent -> ag
        counter add ag 32 -> v1
        ag counter get -> v2
        ag stop agent -> ()
        (v1, v2)

38.3.2. Example 2: Safe Composition and Boundary Handling

Every function in the agent lib is designed to compose cleanly with boolean guards | and with the rest of the 32 libs in ridgun-libs:

import agent

fn :: consultar almacen kv => String Int
      consultar almacen kv =
        new kv agent -> kv
        kv put kv "modo" "produccion" -> ()
        kv get kv "modo" -> modo
        kv count kv -> total
        kv stop agent -> ()
        (modo, total)

38.3.3. Example 3: Actor Combinators (agent ask, try ask, send batch, map batch, drain ready), Sharded Pools, and Connection Reactor

In this hands-on walkthrough we thoroughly exercise how agent behaves across this functional area, covering standard inputs, parameter combinations, and corner cases:

fn :: test spec combinators pool and net agent => ()
      test spec combinators pool and net agent =
        w1 = agent (ag double worker)
        assert int equals (agent ask w1 21) 42 "agent ask 21 -> 42"
        mb = agent map batch w1 [3, 5, 7]
        assert int equals (ag sum ints mb) 30 "agent map batch [3,5,7] -> [6,10,14] sum 30"
        agent send batch w1 [10, 20] -> ()
        rc = agent receive count w1 2
        assert int equals (ag sum ints rc) 60 "agent send batch + agent receive count -> 60"
        c_dr = new counter agent 100
        send 5 to c_dr
        send 10 to c_dr
        dr = agent drain ready c_dr
        assert int equals (ag sum ints dr) 220 "agent drain ready [105, 115] -> 220"
        agent stop all [w1, c_dr] -> ()
        assert false (is agent alive w1) "w1 stopped by agent stop all"
        assert false (is agent alive c_dr) "c_dr stopped by agent stop all"

        s0 = new counter agent 0
        s1 = new counter agent 1000
        pl = Pool 2 [s0, s1]
        assert int equals (pool size pl) 2 "pool size 2"
        assert int equals (pool ask shard pl 0 5) 5 "pool ask shard 0 -> 5"
        assert int equals (pool ask shard pl 1 7) 1007 "pool ask shard 1 -> 1007"
        assert int equals (pool ask shard pl (0 - 3) 3) 1010 "pool ask shard negative key -> shard 1"
        pool broadcast pl 10 -> ()
        all_dr = pool drain all pl
        assert int equals (ag sum ints all_dr) 1035 "pool drain all [15, 1020] -> 1035"
        pool shutdown pl -> ()
        assert false (is agent alive s0) "pool s0 stopped"
        assert false (is agent alive s1) "pool s1 stopped"

        ca = agent (ag echo conn step) (CounterState 0)
        cb = agent (ag echo conn step) (CounterState 0)
        s_eof = conn feed payload (0 - 1) ca ""
        s_err = conn handle event (0 - 1) cb 8
        kept  = reactor sweep next s_eof (reactor sweep next s_err [])
        assert int equals (agent list len kept 0) 0 "reactor sweep next prunes closed slots"
        assert false (is agent alive ca) "ca stopped on EOF"
        assert false (is agent alive cb) "cb stopped on POLLERR"
        cc = agent (ag echo conn step) (CounterState 0)
        reactor shutdown [ConnSlot (0 - 1) cc] -> ()
        assert false (is agent alive cc) "cc stopped on reactor shutdown"

38.3.4. Example 4: Agent Lifecycle (is agent alive, agent status, stop agent) and Isolated Stateful Counter Agent (new counter agent)

In this hands-on walkthrough we thoroughly exercise how agent behaves across this functional area, covering standard inputs, parameter combinations, and corner cases:

fn :: test agent lifecycle and counter => ()
      test agent lifecycle and counter =
        assert str eq (format agent status AgentRunning) "running" "format AgentRunning"
        assert str eq (format agent status AgentStopped) "stopped" "format AgentStopped"
        assert str eq (format agent status (AgentTimedOut 250)) "timeout after 250 ms" "format AgentTimedOut"
        assert str eq (format agent status (AgentFailed "boom")) "failed: boom" "format AgentFailed"
        assert str eq (format agent reply (ReplyInt 42)) "42" "format ReplyInt"
        assert str eq (format agent reply (ReplyStr "ok")) "ok" "format ReplyStr"
        assert str eq (format agent reply (ReplyBool True)) "true" "format ReplyBool True"
        assert str eq (format agent reply (ReplyBool False)) "false" "format ReplyBool False"
        assert str eq (format agent reply ReplyEmpty) "agent outbox empty" "format ReplyEmpty"
        assert str eq (format agent reply ReplyStopped) "agent stopped" "format ReplyStopped"
        assert str eq (format agent reply (ReplyTimeout 50)) "agent timeout after 50 ms" "format ReplyTimeout"
        assert str eq (format agent reply (ReplyError "bad")) "agent error: bad" "format ReplyError"

        c   = new counter agent 10
        assert ok (is agent alive c)
        assert str eq (format agent status (agent status c)) "running" "counter running"
        assert str eq (format agent reply (try poll int c)) "agent outbox empty" "empty outbox before send"
        assert eq (counter get c) 10
        assert eq (counter add c 5) 15
        assert eq (counter add c 7) 22
        assert str eq (format agent reply (ask int c 8)) "30" "ask int 8 -> 30"
        assert str eq (format agent reply (ask int with timeout c 12 200)) "42" "ask int with timeout -> 42"
        assert eq (counter reset c) 0
        assert eq (counter get c) 0
        bs  = ask batch int c [1, 2, 3, 4]
        assert eq (ag sum ints bs) 20

        c2  = new counter agent 100
        rel = relay int c c2 5
        assert str eq (format agent reply rel) "115" "relay int c (10+5=15) -> c2 (100+15=115)"

        st1 = stop agent c
        assert str eq (format agent status st1) "stopped" "stop agent returns AgentStopped"
        assert eq (is agent alive c) False
        assert str eq (format agent status (agent status c)) "stopped" "agent status after stop"
        assert str eq (format agent reply (ask int c 1)) "agent stopped" "ask int after stop"
        assert str eq (format agent reply (try poll int c)) "agent stopped" "try poll int after stop"
        assert str eq (format agent reply (ask int with timeout c 1 50)) "agent stopped" "ask int with timeout after stop"
        assert str eq (format agent reply (relay int c c2 1)) "agent stopped" "relay int after stop"
        c0  = new counter agent 0
        assert int equals (counter get c0) 0 "counter 0 initial"
        assert int equals (counter add c0 3) 3 "counter 0 add 3"
        stop agent c0
        stop agent c2
        assert eq (is agent alive c2) False

38.3.5. Example 5: Append-Only Log Agent (new log agent) and Message-Passing In-Memory Key-Value Store (new kv agent)

In this hands-on walkthrough we thoroughly exercise how agent behaves across this functional area, covering standard inputs, parameter combinations, and corner cases:

fn :: test log and kv agents => ()
      test log and kv agents =
        lg  = new log agent "\n"
        assert ok (is agent alive lg)
        assert str eq (format agent reply (try poll str lg)) "agent outbox empty" "log empty outbox"
        assert str eq (log read lg) "" "initial log empty"
        assert str eq (log append lg "alpha") "alpha" "log append alpha"
        assert str eq (log append lg "beta") "alpha\nbeta" "log append beta"
        assert str eq (format agent reply (ask str with timeout lg "gamma" 200)) "alpha\nbeta\ngamma" "ask str with timeout gamma"
        assert str eq (log read lg) "alpha\nbeta\ngamma" "log read"
        assert str eq (log clear lg) "" "log clear"
        assert str eq (log read lg) "" "log read after clear"
        b   = ask batch str lg ["one", "two"]
        assert str eq (ag join strs b) "one|one\ntwo" "ask batch str"
        lg2 = new log agent ":"
        assert str eq (format agent reply (relay str lg lg2 "three")) "one\ntwo\nthree" "relay str"
        stop agent lg
        stop agent lg2
        assert str eq (format agent reply (ask str lg "x")) "agent stopped" "ask str after stop"

        kv  = new kv agent
        assert ok (is agent alive kv)
        assert int equals (kv count kv) 0 "kv count 0"
        assert false (kv has kv "host") "kv has host false"
        assert str eq (kv put kv "host" "127.0.0.1") "127.0.0.1" "kv put host"
        assert str eq (kv put kv "port" "8080") "8080" "kv put port"
        assert int equals (kv count kv) 2 "kv count 2"
        assert ok (kv has kv "host")
        assert ok (kv has kv "port")
        assert str eq (kv get kv "host") "127.0.0.1" "kv get host"
        assert str eq (kv get kv "port") "8080" "kv get port"
        assert str eq (kv keys kv) "host,port" "kv keys"
        assert str eq (kv put kv "port" "9090") "9090" "kv overwrite port"
        assert str eq (kv get kv "port") "9090" "kv get updated port"
        assert int equals (kv count kv) 2 "kv count after overwrite"
        assert str eq (kv delete kv "host") "127.0.0.1" "kv delete host"
        assert false (kv has kv "host") "kv has host after delete"
        assert int equals (kv count kv) 1 "kv count 1"
        assert str eq (kv clear kv) "" "kv clear"
        assert int equals (kv count kv) 0 "kv count after clear"
        stop agent kv
        assert false (is agent alive kv) "kv stopped"

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38.4. Under the Hood: How agent Is Built in Pure Ridgun (src/main/ridgun/lib/agent.rg)

One of the biggest advantages of ridgun-libs is that there are no C black boxes. You can open src/main/ridgun/lib/agent.rg and read exactly how every operation is implemented using pattern matching, | / |. guard trees, and tail-call optimization (TCO). Let's inspect the key building blocks of its real implementation:

38.4.1. Internal Implementation: Status & Reply Formatting

Observe how agent.rg declares explicit fn :: ... => ... contracts first and resolves each case through aligned equations and tail calls:

module :: agent

fn :: format agent status AgentStatus        => String
      format agent status AgentRunning       =  "running"
      format agent status AgentStopped       =  "stopped"
      format agent status (AgentTimedOut ms) =  "timeout after {ms} ms"
      format agent status (AgentFailed   msg) = "failed: {msg}"

fn :: format agent reply AgentReply        => String
      format agent reply (ReplyInt     n)  =  int to str n
      format agent reply (ReplyStr     s)  =  s
      format agent reply (ReplyBool True)  =  "true"
      format agent reply (ReplyBool False) =  "false"
      format agent reply ReplyEmpty        =  "agent outbox empty"
      format agent reply ReplyStopped      =  "agent stopped"
      format agent reply (ReplyTimeout ms) =  "agent timeout after {ms} ms"
      format agent reply (ReplyError  msg) =  "agent error: {msg}"

38.4.2. Internal Implementation: Core Combinators (agent ask, agent try ask, agent send batch, agent receive count, agent map batch, agent drain ready)

Observe how agent.rg declares explicit fn :: ... => ... contracts first and resolves each case through aligned equations and tail calls:

fn :: agent ask Agent A   => B
      agent ask ag    msg =  ask ag msg

fn :: agent try ask Agent A   => Option
      agent try ask ag    msg =
        send msg to ag
        try receive from ag

fn :: agent send batch Agent [A]      => ()
      agent send batch _     []       =  ()
      agent send batch ag    (m:rest) =
        send m to ag
        agent send batch ag rest

fn :: agent receive count Agent Int   => [B]
      agent receive count ag    count =  agent receive count loop ag count []

fn :: agent receive count loop Agent Int [B] => [B]
      agent receive count loop ag count acc
        | count <= 0 = acc
        | otherwise =
          r = receive from ag
          agent receive count loop ag (count - 1) (acc :: [r])

fn :: agent map batch Agent [A]  => [B]
      agent map batch ag    msgs =
        agent list len msgs 0 -> n
        agent send batch ag msgs -> ()
        agent receive count ag n

fn :: agent list len [A]    Int => Int
      agent list len []     acc =  acc
      agent list len (_:xs) acc =  agent list len xs (acc + 1)

fn :: agent drain ready Agent => [B]
      agent drain ready ag    =  agent drain ready loop ag []

fn :: agent drain ready loop Agent [B] => [B]
      agent drain ready loop ag acc =
        agent drain step ag (try receive from ag) acc

fn :: agent drain step Agent Option [B] => [B]
      agent drain step _ None acc = acc
      agent drain step ag (Some r) acc = agent drain ready loop ag (acc :: [r])

38.4.3. Internal Implementation: Stateful Counter Agent (new counter agent, counter add, counter get, counter reset)

Observe how agent.rg declares explicit fn :: ... => ... contracts first and resolves each case through aligned equations and tail calls:

fn :: ag counter step CounterState Int   => CounterState Int
      ag counter step st           delta =
        | delta == (0 - 999999999) = (CounterState 0, 0)
        | otherwise                =
          nxt = (cnt_val st) + delta
          (CounterState nxt, nxt)

fn :: new counter agent Int  => Agent Int Int
      new counter agent init =  agent (ag counter step) (CounterState init)

fn :: counter add (Agent Int Int) Int   => Int
      counter add ag              delta =
        | not (agent alive ag) = 0
        | otherwise            =
          _ = send delta to ag
          receive from ag

fn :: counter get (Agent Int Int) => Int
      counter get ag              =  counter add ag 0

fn :: counter reset (Agent Int Int) => Int
      counter reset ag              =  counter add ag (0 - 999999999)

38.4.4. Internal Implementation: Stateful In-Memory Key-Value Agent (new kv agent, kv put, kv get, kv delete, kv has, kv count, kv keys, kv clear)

Observe how agent.rg declares explicit fn :: ... => ... contracts first and resolves each case through aligned equations and tail calls:

fn :: ag kv lookup [KvEntry] String => String
      ag kv lookup []        _      =  ""
      ag kv lookup (e:rest)  key    =
        | (kv_k e) == key = kv_v e
        | otherwise       = ag kv lookup rest key

fn :: ag kv exists [KvEntry] String => Bool
      ag kv exists []        _      =  False
      ag kv exists (e:rest)  key    =
        | (kv_k e) == key = True
        | otherwise       = ag kv exists rest key

fn :: ag kv put list [KvEntry] String String => [KvEntry]
      ag kv put list [] key val = [KvEntry key val]
      ag kv put list (e:rest) key val =
        | (kv_k e) == key = [KvEntry key val] :: rest
        | otherwise       = [e] :: (ag kv put list rest key val)

fn :: ag kv del list [KvEntry] String => [KvEntry]
      ag kv del list [] _ = []
      ag kv del list (e:rest) key =
        | (kv_k e) == key = rest
        | otherwise       = [e] :: (ag kv del list rest key)

fn :: ag kv len [KvEntry] => Int
      ag kv len []        =  0
      ag kv len (_:rest)  =  1 + (ag kv len rest)

fn :: ag kv keys join String String => String
      ag kv keys join k rest_s =
        | (str len rest_s) == 0 = k
        | otherwise             = k + "," + rest_s

fn :: ag kv keys str [KvEntry] => String
      ag kv keys str []        =  ""
      ag kv keys str (e:rest)  =  ag kv keys join (kv_k e) (ag kv keys str rest)

fn :: ag kv has str Bool  => String
      ag kv has str True  =  "1"
      ag kv has str False =  "0"

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38.5. Algorithmic Guarantees, RMM1/RMM2 Memory, and the 5 Golden Rules of agent

• Algorithmic & Safety Guarantee: Zero shared mutable memory across actors: every message is transferred by value / Copy-on-Write and stop deterministically reclaims the actor's region.
• $O(1)$ Stack Complexity via TCO: Every recursive loop in src/main/ridgun/lib/agent.rg is in tail position, so ridgunc compiles them into native jumps with zero stack growth.
• Deterministic Memory (RMM1/RMM2): Zero garbage-collector pauses; all intermediate allocations are reclaimed deterministically on scope exit.
• Continuous Verification: Statically checked via stable check and tested by the automated suite in src/test/ridgun/test agent.rg.

The 5 Golden Rules When Programming with agent

1. Declare import agent at the top of your file and take advantage of space/underscore equivalence so your code reads like natural prose.
2. Align your data pipelines with =: chain agent calls into named intermediate steps and let stable format align the columns.
3. Leverage agent's total functions inside | guards: inspect return values or unwrap ADTs via pattern matching rather than assuming external input is valid.
4. Avoid cloning large structures when only reading: remember that under RMM2, function input arguments incur zero reference-count overhead (+0 / -0).
5. Pair agent with test (import test): always lock in your domain invariants with assert equals or assert true.

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In Chapter 39, we will explore the pool lib in full depth (The pool Lib — Bounded Worker Pool, Round-Robin Dispatch, and Work-Stealing).