Expression

Expression

Expression represents the closure of the value inside expect(...). Expressions are memoized by default. This makes them safe to call evaluate() multiple times without causing a re-evaluation of the underlying closure.

public struct Expression<T>

@warning Since the closure can be any code, Objective-C code may choose to raise an exception. Currently, Expression does not memoize exception raising.

This provides a common consumable API for matchers to utilize to allow Nimble to change internals to how the captured closure is managed.

Initializers

init(expression:location:isClosure:)

Creates a new expression struct. Normally, expect(...) will manage this creation process. The expression is memoized.

public init(expression: @escaping () throws -> T?, location: SourceLocation, isClosure: Bool = true)

@param expression The closure that produces a given value. @param location The source location that this closure originates from. @param isClosure A bool indicating if the captured expression is a closure or internally produced closure. Some matchers may require closures. For example, toEventually() requires an explicit closure. This gives Nimble flexibility if @autoclosure behavior changes between Swift versions. Nimble internals always sets this true.

init(memoizedExpression:location:withoutCaching:isClosure:)

Creates a new expression struct. Normally, expect(...) will manage this creation process.

public init(memoizedExpression: @escaping (Bool) throws -> T?, location: SourceLocation, withoutCaching: Bool, isClosure: Bool = true)

@param expression The closure that produces a given value. @param location The source location that this closure originates from. @param withoutCaching Indicates if the struct should memoize the given closure's result. Subsequent evaluate() calls will not call the given closure if this is true. @param isClosure A bool indicating if the captured expression is a closure or internally produced closure. Some matchers may require closures. For example, toEventually() requires an explicit closure. This gives Nimble flexibility if @autoclosure behavior changes between Swift versions. Nimble internals always sets this true.

init(expression:location:isClosure:)

Creates a new expression struct. Normally, expect(...) will manage this creation process. The expression is memoized.

public init(expression: @escaping () throws -> T?, location: SourceLocation, isClosure: Bool = true)

@param expression The closure that produces a given value. @param location The source location that this closure originates from. @param isClosure A bool indicating if the captured expression is a closure or internally produced closure. Some matchers may require closures. For example, toEventually() requires an explicit closure. This gives Nimble flexibility if @autoclosure behavior changes between Swift versions. Nimble internals always sets this true.

init(memoizedExpression:location:withoutCaching:isClosure:)

Creates a new expression struct. Normally, expect(...) will manage this creation process.

public init(memoizedExpression: @escaping (Bool) throws -> T?, location: SourceLocation, withoutCaching: Bool, isClosure: Bool = true)

@param expression The closure that produces a given value. @param location The source location that this closure originates from. @param withoutCaching Indicates if the struct should memoize the given closure's result. Subsequent evaluate() calls will not call the given closure if this is true. @param isClosure A bool indicating if the captured expression is a closure or internally produced closure. Some matchers may require closures. For example, toEventually() requires an explicit closure. This gives Nimble flexibility if @autoclosure behavior changes between Swift versions. Nimble internals always sets this true.

Properties

location

let location: SourceLocation

isClosure

let isClosure: Bool

location

let location: SourceLocation

isClosure

let isClosure: Bool

Methods

cast(_:)

Returns a new Expression from the given expression. Identical to a map() on this type. This should be used only to typecast the Expression's closure value.

public func cast<U>(_ block: @escaping (T?) throws -> U?) -> Expression<U>

The returned expression will preserve location and isClosure.

@param block The block that can cast the current Expression value to a new type.

evaluate()

public func evaluate() throws -> T?

withoutCaching()

public func withoutCaching() -> Expression<T>

cast(_:)

Returns a new Expression from the given expression. Identical to a map() on this type. This should be used only to typecast the Expression's closure value.

public func cast<U>(_ block: @escaping (T?) throws -> U?) -> Expression<U>

The returned expression will preserve location and isClosure.

@param block The block that can cast the current Expression value to a new type.

evaluate()

public func evaluate() throws -> T?

withoutCaching()

public func withoutCaching() -> Expression<T>