@usine/expression/expression-engine

Classes

Environment

The types and root variables an expression is checked and evaluated against.

Extends

• Schema.Class

Constructors

Constructor

new Environment(…args): Environment

Parameters

Parameter	Type
…args	[props: object, options?: MakeOptions]

Returns

Environment

Properties

types

readonly types: readonly ObjectType[]

variables

readonly variables: readonly Variable[]

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ExpressionCheckError

The expression failed to parse, to type-check, or to produce the expected result type.

Extends

• Schema.Class

Constructors

Constructor

new ExpressionCheckError(…args): ExpressionCheckError

Parameters

Parameter	Type
…args	[props: object, options?: MakeOptions]

Returns

ExpressionCheckError

Properties

code

readonly code: "check_failed" | "parse_error" | "type_error" | "unexpected_result_type"

message

readonly message: string

position

readonly position: Option<number>

source

readonly source: string & Brand<"ExpressionSource">

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ExpressionEngine

Evaluates Loop conditions and prompt expressions against their declared payload context.

Extends

• Context.ServiceClass

Properties

Service

readonly Service: ExpressionEngineService

The service’s operations: what yield* ExpressionEngine returns.

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ExpressionEvaluationError

Evaluation failed on an expression that had already checked.

Extends

• Schema.Class

Constructors

Constructor

new ExpressionEvaluationError(…args): ExpressionEvaluationError

Parameters

Parameter	Type
…args	[props: object, options?: MakeOptions]

Returns

ExpressionEvaluationError

Properties

message

readonly message: string

source

readonly source: string & Brand<"ExpressionSource">

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ObjectField

One named field and its CEL type within an object descriptor.

Extends

• Schema.Class

Constructors

Constructor

new ObjectField(…args): ObjectField

Parameters

Parameter	Type
…args	[props: object, options?: MakeOptions]

Returns

ObjectField

Properties

name

readonly name: string

type

readonly type: string & Brand<"CelTypeReference">

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ObjectType

A CEL object type. Declare a type before the types that reference it.

Extends

• Schema.Class

Constructors

Constructor

new ObjectType(…args): ObjectType

Parameters

Parameter	Type
…args	[props: object, options?: MakeOptions]

Returns

ObjectType

Properties

fields

readonly fields: readonly ObjectField[]

name

readonly name: string

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Variable

A root variable available to CEL expressions in an Environment.

Extends

• Schema.Class

Constructors

Constructor

new Variable(…args): Variable

Parameters

Parameter	Type
…args	[props: object, options?: MakeOptions]

Returns

Variable

Properties

name

readonly name: string

type

readonly type: string & Brand<"CelTypeReference">

Interfaces

ExpressionEngineService

Checks and evaluates the expressions used to select Items and fill Loop task templates.

Properties

checkBoolean

readonly checkBoolean: (source, environment) => Effect<void, ExpressionCheckError>

Checks whether the expression can select Items, without evaluating a payload.

Parameters

Parameter	Type
source	string & Brand<"ExpressionSource">
environment	Environment

Returns

Effect<void, ExpressionCheckError>

checkScalar

readonly checkScalar: (source, environment) => Effect<void, ExpressionCheckError>

Checks whether the expression can produce one value for prompt interpolation.

Parameters

Parameter	Type
source	string & Brand<"ExpressionSource">
environment	Environment

Returns

Effect<void, ExpressionCheckError>

evaluateBoolean

readonly evaluateBoolean: (source, environment, context) => Effect<boolean, ExpressionCheckError | ExpressionEvaluationError>

Checks and evaluates a selection condition; context supplies values for the environment’s root variables.

Parameters

Parameter	Type
source	string & Brand<"ExpressionSource">
environment	Environment
context	JsonObject

Returns

Effect<boolean, ExpressionCheckError | ExpressionEvaluationError>

evaluateScalar

readonly evaluateScalar: (source, environment, context) => Effect<string | number | bigint | boolean | null, ExpressionCheckError | ExpressionEvaluationError>

Checks and evaluates a prompt interpolation; context supplies values for the environment’s root variables.

Parameters

Parameter	Type
source	string & Brand<"ExpressionSource">
environment	Environment
context	JsonObject

Returns

Effect<string | number | bigint | boolean | null, ExpressionCheckError | ExpressionEvaluationError>

relatedStringLiterals

readonly relatedStringLiterals: (source, memberPath) => Effect<readonly string[], ExpressionCheckError>

The string literals the expression compares against the name field of values reached from memberPath, following macro bindings and collection transformations. Config validation uses it to spot undeclared labels.

Parameters

Parameter	Type
source	string & Brand<"ExpressionSource">
memberPath	readonly string[]

Returns

Effect<readonly string[], ExpressionCheckError>

Type Aliases

CheckErrorCode

CheckErrorCode = typeof CheckErrorCode.Type

Whether checking failed during parsing, type resolution, or result-type validation.

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ExpressionError

ExpressionError = typeof ExpressionError.Type

The failures callers can receive when checking or evaluating a CEL expression.

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Scalar

Scalar = typeof Scalar.Type

Values prompt interpolation can render. CEL ints stay bigint.

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Source

Source = typeof Source.Type

Non-blank CEL source text.

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TypeReference

TypeReference = typeof TypeReference.Type

A type name in CEL syntax such as string, Issue, or list<Label>.

Variables

CheckErrorCode

const CheckErrorCode: Schema.Literals<readonly ["check_failed", "parse_error", "type_error", "unexpected_result_type"]>

Whether checking failed during parsing, type resolution, or result-type validation.

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ExpressionError

const ExpressionError: Schema.Union<readonly [typeof ExpressionCheckError, typeof ExpressionEvaluationError]>

The failures callers can receive when checking or evaluating a CEL expression.

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Scalar

const Scalar: Schema.Union<readonly [Schema.String, Schema.Number, Schema.BigInt, Schema.Boolean, Schema.Null]>

Values prompt interpolation can render. CEL ints stay bigint.

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Source

const Source: Schema.brand<Schema.String, "ExpressionSource">

Non-blank CEL source text.

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TypeReference

const TypeReference: Schema.brand<Schema.String, "CelTypeReference">

A type name in CEL syntax such as string, Issue, or list<Label>.