Generative Story Worldsas

Linear Logic ProgramsChris Martens, João Ferreira,

Anne-Gwenn Bosser, and Marc Cavazza

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Presented at Interactive Narrative TechnologiesJune 18, 2014

Generative Story Worldsas

Linear Logic ProgramsChris Martens, João Ferreira,

Anne-Gwenn Bosser, and Marc Cavazza

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Presented at Interactive Narrative TechnologiesJune 18, 2014

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new programming languages for digital narratives

Praxis & Prompter:

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OLD programming languages for digital narratives(?)

LOGIC

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old programming languages for digital narratives

LINEAR LOGIC

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used linear logic as a programming language (Celf)for specifying narrative worlds;

used proof search to generate structured stories.

What we did:

THREE ACTS

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I. Setup: agent simulation, linear logic, andlogic programming

II. Payoff: Stories as Proofs

III. Promise and Limitations

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greetinsult

complimentgossip

flirt...

social verbs: social state:

knowledgesentiment

emotional statepersonality

belief

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verbs: rulescausal relationships: resource dependencies

RULES

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Narrative Actions~

Logical implication

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the problem with standard logical implication:

buy_soda :has(Alice, $1) ^ wants(Alice, soda) ⇒

has(Alice, soda)

LINEAR LOGIC

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A -o B

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buy_soda :has(Alice, $1) * wants(Alice, soda) -o

has(Alice, soda)

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A * BA -o B

!A

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A * BA -o {B}

!A

Logic Programming

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proof search as program execution

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initial state

Σ Δ0

Celf

query(optional)

A

Δ0, …, ΔΔ ⊢ A?

narrative actions

Logic Programming

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A -o {B}

Δ, A → Δ, B

Δ = arbitrary context of resources A1, …, An

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Example in our paper:Shakespearean tragedy world

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Shakespearean tragedy world

state components:character location, possession,

sentiment toward other characters,goals

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Shakespearean tragedy worldat <character> <location>has <character> <object>

anger <character> <character>philia <character> <character>

depressed <character>

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Shakespearean tragedy world

!dead <character>!killed <character> <character>

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do/insult :

at C L * at C’ L * anger C C’

-o {at C L * at C’ L * anger C C’ anger C’ C * depressed C’}.

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do/compliment :

at C L * at C’ L * philia C C’

-o {at C L * at C’ L * philia C C’ * philia C’ C}.

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do/murder : anger C C’ * anger C C’ * anger C C’ * anger C C’ * at C L * at C’ L * has C weapon-o {at C L * !dead C’ * !murdered C C’ * has C weapon}.

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do/mourn : at C L * philia C C’ * dead C’-o {philia C C’ * at C L * depressed C * depressed C}.

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do/becomeSuicidal :

at C L * depressed C * depressed C * depressed C * depressed C

-o {at C L * suicidal C * wants C weapon}.

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do/loot

: at C L * dead C' * has C' O * wants C O

-o {at C L * has C O}.

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do/comfort : at C L * at C' L *suicidal C' * philia C C' * philia C' C -o {at C L * at C' L * philia C C' * philia C' C * philia C' C}.

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initial state

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story_start :init -o

{ at romeo town * at montague mon_house * at capulet cap_house * at mercutio town * at nurse cap_house * at juliet town * at tybalt town * at apothecary town *

has tybalt weapon * has romeo weapon * has apothecary weapon *

...

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... * anger montague capulet * anger capulet montague * anger tybalt romeo * anger capulet romeo * anger montague tybalt *

philia mercutio romeo * philia romeo mercutio * philia montague romeo * philia capulet juliet * philia juliet nurse * philia nurse juliet *

neutral nurse romeo * neutral mercutio juliet * neutral juliet mercutio * neutral apothecary nurse * neutral nurse apothecary}.

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final state

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ending_happy : nonfinal *

actor C * actor C’ *at C L * at C’ L * married C C’ -o {final}.

ending_vengeance : nonfinal *

actor C1 * actor C2 * actor C3 *killed C1 C2 * philia C3 C2 * killed C3 C1

-o {final}.

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proofs as stories

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query:init -o {final}

Nondeterminism

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A -o {B}

Δ, B

A -o {C}

Δ, C

Δ, A

Nondeterminism

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A -o {B} C -o {D}

Nondeterminism

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A -o {B}

Δ, B, C

C -o {D}

Δ, A, D

Δ, A, C

Nondeterminism

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A -o {B}

Δ, B, C

C -o {D}

Δ, A, D

Δ, A, C

Δ, B, D

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proof ofinit -o {final}:

function (x:init) =let [xs] = r [ys] in …

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...let {[X73, [X74, [X75, [X76, X77]]]]}

= do/insult/private [a-tybalt, [a-romeo, [X68, [X66, X72]]]] in

let {[X85, [X86, X87]]}

= do/becomeSuicidal [a-romeo, [X79, [X41, [X59, [X52, X77]]]]] in

let {[X88, [X89, [X90, [X91, X92]]]]}

= do/comfort [a-mercutio, [a-romeo, [X78, [X85, [X86, [X81, X83]]]]]] in

let {[X101, [!X102, [!X103, X104]]]}

= do/murder [a-romeo, [a-tybalt, [X58, [X40, [X76, [X51, [X94, [X96, X27]]]]]]]] in

let {[X105, [X106, [X107, X108]]]}

= do/compliment/private [a-nurse, [a-juliet, [X46, [X47, X30]]]] in

let {[X109, [X110, [X111, X112]]]}

= do/compliment/private [a-juliet, [a-nurse, [X106, [X105, X108]]]] in

let {[X113, X114]}= do/loot [a-romeo, [a-tybalt, [X101, [X102, [X26, X87]]]]] in

...

Concurrent Equality

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r1: A -o B r2: C -o D

“apply r1; apply r2” ~= “apply r2; apply r1”

if A and C are disjoint

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graphical representation of traces

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init

do/insult/privatedo/formOpinion/dislike

do/compliment/witnessed

do/travelTo

do/compliment/private

do/murder

do/marry

ending_1

do/steal

do/thinkVengefully

do/mourn

do/becomeSuicidal

cleanup/1

do/eroticize

do/suicide

do/flirt/discrete

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init

do/insult/privatedo/formOpinion/dislike

do/compliment/witnessed

do/travelTo

do/compliment/private

do/murder

do/marry

ending_1

do/steal

do/thinkVengefully

do/mourn

do/becomeSuicidal

cleanup/1

do/eroticize

do/suicide

do/flirt/discrete

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queries on sets of traces

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> exists ending_1

> exists do/thinkVengefully && ̃link do/thinkVengefully do/murder

generative exploration

informative structure

character perspective-agnosticism

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what does this accomplish?

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how do simulation designs fail their authors?

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orphan verbsvs causally connected chains

ACT III

Potential & Limitations

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combining reactive/exploratory+ goal-driven behavior:

A -o G vs A -o {B}(backward & forward chaining)

Additional potential of LL

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higher-order rules: (A -o B) -o C

Additional potential of LL

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higher-order rules: (A -o B) -o C

“serendipity:”Forall L. at romeo L * at juliet L -o {eros romeo juliet * at romeo L * at juliet L})

Additional potential of LL

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Additional potential of LL

dynamic object generation: Exists x:A. ...

makeRoom : has(C, magic door) * at C R -o {Exists r:room. !adjacent R r}

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limitations

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limitations(of the tool)

(of the underlying formalism)

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limitations of the tool:interactivity

history trackingdebugging facilitiesdrama management

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limitations of the formalism:ability to broadcast actions

nondeterminism and control over probabilities

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what I plan to address:interactivity

debugging facilitiesability to “broadcast” actions

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PHASES

Phases (Example)

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deduplication

phase act {…

} quiesced act -o {phase dedup}.

phase dedup { wants C O * wants C O -o {wants C O}. } quiesced dedup -o {phase act}.

Phases

phase p1 = {...}phase p2 = {...}

quiesced p1 -o {some_token * phase p2}.

quiesced p2 -o {phase p1}.

Blocks connected by specification of quiescence behavior

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Phases (Example)interactivity

phase world = { rule1 : do Action * … -o {…}. rule2 : do Action * … -o {…}.}

phase player = {get_input : player_turn -o {read #STDIN}.

}

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also possible to implement: broadcast

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also ongoing:phase invariants

for each phase, constraints on the context…- as an invariant of the phase

- at quiescence

programmer-specified, machine-checked!

FINALE

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the point of formalismis to be able to run

readable specifications

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the point of formalismis to be able to reason about

readable specifications

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linear logic can be used as a programming language for specifying narrative worlds;

to generate narratives& analyze their structure;

potentially the basis for a richer PL.

Takeaway

FINALE

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Celf: https://github.com/clf/celf

Example from the paper:http://tinyurl.com/int2014-clf

Me: Chris Martens@chrisamaphone

cmartens@cs.cmu.eduPlanning to graduate Summer 2015

MINUS WORLD(bonus slides)

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Cut

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Δ1 ⊢ A Δ 2, A ⊢ CΔ 1, Δ 2 ⊢ C

Frame Property

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If Δ1 ⊢ Athen

Δ1, Δ2 ⊢ A * ⨂Δ2

Frame Property (alt)

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If Δ1 → Δ2

then Δ1, Δ’ → Δ2, Δ’

Relationship between step and deductions

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Δ1 → Δ2

iff for all CΔ2 ⊢ C implies Δ1 ⊢ C

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LOGICSare formalisms with

composable consequences

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LOGICSare formalisms with

composable consequences

Δ ⊢ A Δ’, A ⊢ CΔ’, Δ ⊢ C

Phases (Example)Broadcast

phase act { do C A * in_room C R -o {broadcast C A R}. }quiesced act -o {phase broadcast}.

phase broadcast { broadcast C A R * in_room C' R -o

{notice C' C A * broadcast C A R}. }quiesced broadcast -o {phase notice}.

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Phases (Example)Broadcast

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phase notice { broadcast C A R * notice C' C A -o {react C' C A * in_room C' R * broadcast C A R}. }

quiesced notice * broadcast _ _ _ -o {phase react}.

phase react { react C C' (murder ...) * philia C C' -o {...}}

quiesced react -o {phase act}.

Phasesdelimited subsignatures connected by specifications of quiescence behavior.

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quiesced P * State -o {phase P’ * State’}.

arbitrarily many phaseslooping + branching