Glossary

What follows is an alphabetized glossary of terms defined in this reference.

Each entry below links to the section where the term is introduced.

Action: A construct specifying something a character can do in the storyworld. See Actions.
Action body: The fields that make up an action definition. See Action body.
Action header: The portion of an action definition that declares its name, markers, and inheritance. See Action header.
Action name: The unique identifier for an action definition. See Action name.
Action search: An expression that searches over a character’s memories or the chronicle, optionally filtered by a query. See Action searches.
Action targeting: The runtime process of determining whether an action can be performed. See Action targeting.
Adapter: The interface through which the host application exposes read–write capabilities to the Viv runtime. See Introduction.
Arithmetic expression: An expression applying a binary arithmetic operator. See Arithmetic expressions.
Assignment expression: An expression that modifies a value in the host application. See Assignment expressions.
Associations: Per-character tag-like annotations attached to an action memory. See Associations.
Binding entry: A mapping from a role reference to an expression in a bindings block. See Binding entries.
Bindings: Precast role values supplied to a targeted construct. See Bindings.
Boolean literals: The values true and false. See Booleans.
Casting pool: The set of candidates from which a role is cast. See Casting pool.
Casting-pool directive: A role field specifying a custom casting pool. See Casting pool.
Chance expression: An expression that evaluates to true with a specified probability. See Chance expressions.
Child action: An action that inherits from a parent action. See Inheritance.
Chronicle: The complete record of all actions performed in a simulation. See Search domains.
Comment: Text introduced with // that is ignored by the grammar. See Comments.
Concatenated source: The result of merging all included files into a single logical source. See Concatenated source.
Conditional: An if/elif/else/end control-flow construct. See Conditionals.
Constants: Tokens with special fixed values. See Constants.
Content bundle: The compiled JSON artifact consumed by a Viv runtime. See Compiler output.
Custom function call: An invocation of a host-application function via the ~ operator. See Custom function calls.
Dehydration: The conversion of entity data to entity IDs before passing values across boundaries. See Dehydration.
Embargo: A declaration constraining the subsequent performance of an action. See Embargoes.
Entity: Anything in the storyworld with a persistent identity managed by the host application. See Entities.
Entity ID: A unique string identifier for an entity, provisioned by the host application. See Entities.
Entity view: The data object furnished by the host application for a given entity. See Entities.
Enum literal: An identifier preceded by #, representing a named value. See Enums.
Evaluation context: The set of bindings and state available during expression evaluation. See Evaluation context.
Expression: A construct that evaluates to a value. See Expressions.
Fail-safe marker: The ? token, which causes missing values to yield null rather than errors. See Fail-safe marker.
General action: An action that may be targeted anytime (not reserved). See Reserved marker.
Global condition: A condition that references no roles and is tested before role casting. See Condition grouping.
Gloss: A brief string or template string describing an action instance. See Gloss.
Group role: A role with a slots maximum greater than one. See Group roles.
Group-role decorator: The * token appended to a role reference to mark it as a group role. See Group-role decorator.
Hearer (@hearer): A special role reference bound to the character hearing about an action after the fact, via knowledge relaying. See Evaluation context.
Host application: The project (typically a videogame) that integrates the Viv runtime. See Introduction.
Identifier: An author-defined name for a construct, role, or variable. See Identifiers.
Include: A statement that imports constructs from another Viv source file. See Includes.
Inheritance: The mechanism by which a child action incorporates material from a parent action. See Inheritance.
Inscription: An expression that records knowledge of an action onto an item. See Inscriptions.
Inspection: An expression that causes a character to learn about actions inscribed on an item. See Inspections.
Joinable: A field that may be merged (rather than overridden) during inheritance. See Field joinability.
Keywords: Tokens with special meaning in the grammar. See Keywords.
List literal: An ordered sequence of expressions in brackets. See Lists.
Local variable: A variable scoped to a single block, prefixed with _. See Local variables.
Logical expression: An expression combining tests with && and ||. See Logical expressions.
Loop: A loop/as/end iteration construct. See Loops.
Metadata: Version and validation data in the content bundle. See Metadata.
Null literal: The value null. See Null.
Number literal: A decimal integer or fraction. See Numbers.
Numeric criterion: A threshold test on a numeric value in a query. See Numeric criteria.
Object literal: Key–value pairs in a JavaScript-like notation. See Objects.
Operators: Tokens that perform computations or comparisons. See Operators.
Optional role: A role with a slots minimum of zero. See Slots range.
Optional slot: A slot beyond the minimum that may or may not be filled. See Slots range.
Orderless: The property that constructs in a source file have no meaningful order. See Source units are orderless.
Parent action: An action from which a child action inherits. See Inheritance.
Plan: A multi-phase sequence of coordinated reactions. See Plans.
Plan instruction: A building block of a plan phase. See Plan instructions.
Plan phase: A named stage in a plan, prefixed with >. See Phases.
Positional binding: A sugared binding matched to roles by position rather than name. See Positional bindings.
Query: A pattern for searching over recorded action instances. See Queries.
Reaction: A declaration that queues a construct for future execution. See Reactions.
Reaction window: A plan construct that groups instructions with a completion policy. See Reaction windows.
Reference: The primary way to name and access a role binding or variable. See References.
Reference path: A chain of property, pointer, or lookup accesses extending a reference. See Reference paths.
Relational expression: An expression comparing two operands. See Relational operators.
Report: A longer string or template string describing an action instance. See Report.
Required slot: A slot that must be filled for targeting to succeed. See Slots range.
Reserved action: An action that may only be targeted via a reaction or selector. See Reserved marker.
Reserved word: A keyword that cannot be used as an identifier. See Identifiers.
Role: A slot in the cast of a construct, filled with an entity or symbol at runtime. See Roles.
Role body: The fields that make up a role definition. See Role body.
Role label: A keyword specifying a role’s entity type and casting behavior. See Labels.
Role reference: A sigil-prefixed identifier naming a role. See Role reference.
Role-dependency forest: A tree structure governing the order in which roles are cast. See Role dependency trees.
Salience: A per-character numeric score representing how memorable an action is. See Saliences.
Scope sigil: A sigil ($ or _) indicating storage scope. See Scope sigils.
Scratch variable: A temporary variable scoped to an action definition, prefixed with $. See Scratch.
Search domain: The collection of action instances to search over. See Search domains.
Selector: A construct specifying a set of candidates and a policy for choosing among them. See Selectors.
Set predicate: A test on the relationship between an actual set and a specified set. See Set predicates.
Sifting expression: An expression that invokes a sifting pattern. See Sifting expressions.
Sifting pattern: A pattern describing a causally related sequence of actions. See Sifting patterns.
Sigil: A single-character token prefixing a name to indicate type or scope. See Sigils.
Slots: Parameters controlling how many entities fill a role. See Slots.
Spawn directive: A role field specifying an adapter function to construct a new entity. See Spawn directive.
Statement: A conditional, loop, reaction, or expression. See Statements.
Story sifting: The detection of emergent storylines via sifting patterns. See Sifting patterns.
String literal: A quoted string value. See Strings.
Sugared bindings: Compact inline bindings enclosed in angle brackets. See Sugared bindings.
Symbol: A value that does not correspond to a host-application entity. See Symbols.
Target: The file path specified in an include statement. See Targets.
Target group: The set of candidates and selection policy in a selector. See Target group.
Target policy: The strategy for choosing among selector candidates. See Target policies.
Template action: An action intended solely for inheritance, excluded from the content bundle. See Template marker.
Template gap: An interpolation point in a template string. See Template strings.
Template string: A string with interpolated expressions. See Template strings.
Temporal constraint: A restriction on when a reaction or query match is valid. See Temporal constraints.
This (@this): A special reference to the action instance currently being executed. See Evaluation context.
Time period: A duration comprising a quantity and a unit. See Time periods.
Time-frame anchor: The reference point for a time-frame constraint. See Time-frame anchors.
Time-frame constraint: A temporal constraint specifying a window relative to an anchor. See Time-frame constraints.
Time-of-day constraint: A temporal constraint specifying clock-time boundaries. See Time-of-day constraints.
Token: The smallest unit of meaning recognized by the grammar. See Tokens.
Trope: A relational pattern among entities that can be tested at runtime. See Tropes.
Trope fit: An expression testing whether a trope matches for given bindings. See Trope fits.
Type sigil: A sigil (@ or &) indicating entity or symbol type. See Type sigils.
Wait instruction: A plan instruction that pauses execution for a duration. See Wait.