Gen

Namespace: FsCheck

Combinators to build custom random generators for any type.

Functions and values

Function or value	Description
`apply f gn` Signature: f:Gen<('a -> 'b)> -> gn:Gen<'a> -> Gen<'b> Type parameters: 'a, 'b Attributes: [<CompiledName("Apply")>]	Apply the given Gen function to the given generator, aka the applicative <*> operator. CompiledName: `Apply`
`array2DOf(g)` Signature: g:Gen<'a> -> Gen<'a [,]> Type parameters: 'a Attributes: [<CompiledName("Array2DOf")>]	Generates a 2D array. The square root of the size is the maximum number of rows and columns. CompiledName: `Array2DOf`
`array2DOfDim(rows, cols) g` Signature: (rows:int * cols:int) -> g:Gen<'a> -> Gen<'a [,]> Type parameters: 'a Attributes: [<CompiledName("Array2DOf")>]	Generates a 2D array of the given dimensions. CompiledName: `Array2DOf`
`arrayOf(g)` Signature: g:Gen<'a> -> Gen<'a []> Type parameters: 'a Attributes: [<CompiledName("ArrayOf")>]	Generates an array using the specified generator. The maximum length is the size+1. CompiledName: `ArrayOf`
`arrayOfLength n g` Signature: n:int -> g:Gen<'a> -> Gen<'a []> Type parameters: 'a Attributes: [<CompiledName("ArrayOf")>]	Generates an array of a specified length. CompiledName: `ArrayOf`
`choose(l, h)` Signature: (l:int * h:int) -> Gen<int> Attributes: [<CompiledName("Choose")>]	Generates an integer between l and h, inclusive. CompiledName: `Choose`
`constant(v)` Signature: v:'b -> Gen<'b> Type parameters: 'b Attributes: [<CompiledName("Constant")>]	Always generate the same instance v. See also fresh. CompiledName: `Constant`
`elements(xs)` Signature: xs:seq<'a> -> Gen<'a> Type parameters: 'a Attributes: [<CompiledName("Elements")>]	Build a generator that randomly generates one of the values in the given non-empty seq. CompiledName: `Elements`
`elementsArr(values)` Signature: values:'?202630 array -> Gen<'?202630> Type parameters: '?202630 Attributes: [<CompiledName("Elements")>] [<CompilerMessage("This method is not intended for use from F#.", 10001, IsHidden = true, IsError = false)>]	Build a generator that randomly generates one of the values in the given non-empty seq. CompiledName: `Elements`
`eval size seed arg3` Signature: size:int -> seed:StdGen -> Gen<'b> -> 'b Type parameters: 'b Attributes: [<CompiledName("Eval")>]	Generates a value of the give size with the given seed. CompiledName: `Eval`
`filter predicate generator` Signature: predicate:('a18 -> bool) -> generator:Gen<'a18> -> Gen<'a18> Type parameters: 'a18 Attributes: [<CompiledName("Filter")>]	Generates a value that satisfies a predicate. Contrary to tryFilter, this function keeps re-trying by increasing the size of the original generator ad infinitum. Make sure there is a high probability that the predicate is satisfied. The `filter` function is an alias for the `where` function. These two functions are identical, but co-exist so that you can choose the word that makes your code most readable in your given context. CompiledName: `Filter`
`four(g)` Signature: g:Gen<'b> -> Gen<'b * 'b * 'b * 'b> Type parameters: 'b Attributes: [<CompiledName("Four")>]	Build a generator that generates a 4-tuple of the values generated by the given generator. CompiledName: `Four`
`frequency(xs)` Signature: xs:seq<int * Gen<'a18>> -> Gen<'a18> Type parameters: 'a18 Attributes: [<CompiledName("Frequency")>]	Build a generator that generates a value from one of the generators in the given non-empty seq, with given probabilities. The sum of the probabilities must be larger than zero. CompiledName: `Frequency`
`frequencySeqWeightAndValue(...)` Signature: weightedValues:seq<WeightAndValue<Gen<'a>>> -> Gen<'a> Type parameters: 'a Attributes: [<CompiledName("Frequency")>] [<CompilerMessage("This method is not intended for use from F#.", 10001, IsHidden = true, IsError = false)>]	Build a generator that generates a value from one of the generators in the given non-empty seq, with given probabilities. The sum of the probabilities must be larger than zero. CompiledName: `Frequency`
`frequencyTupleArr(weightedValues)` Signature: weightedValues:(int * Gen<'a>) [] -> Gen<'a> Type parameters: 'a Attributes: [<CompiledName("Frequency")>] [<CompilerMessage("This method is not intended for use from F#.", 10001, IsHidden = true, IsError = false)>]	Build a generator that generates a value from one of the generators in the given non-empty seq, with given probabilities. The sum of the probabilities must be larger than zero. CompiledName: `Frequency`
`frequencyWeightAndValueArr(...)` Signature: weightedValues:WeightAndValue<Gen<'a>> [] -> Gen<'a> Type parameters: 'a Attributes: [<CompiledName("Frequency")>] [<CompilerMessage("This method is not intended for use from F#.", 10001, IsHidden = true, IsError = false)>]	Build a generator that generates a value from one of the generators in the given non-empty seq, with given probabilities. The sum of the probabilities must be larger than zero. CompiledName: `Frequency`
`fresh(fv)` Signature: fv:(unit -> '?202612) -> Gen<'?202612> Type parameters: '?202612 Attributes: [<CompiledName("Fresh")>]	Generate a fresh instance every time the generator is called. Useful for mutable objects. See also constant. CompiledName: `Fresh`
`freshFunc(fv)` Signature: fv:Func<'?202614> -> Gen<'?202614> Type parameters: '?202614 Attributes: [<CompiledName("Fresh")>] [<CompilerMessage("This method is not intended for use from F#.", 10001, IsHidden = true, IsError = false)>]	Generate a fresh instance every time the generatoris called. Useful for mutable objects. See also constant. CompiledName: `Fresh`
`growingElements(xs)` Signature: xs:seq<'?202634> -> Gen<'?202634> Type parameters: '?202634 Attributes: [<CompiledName("GrowingElements")>]	Build a generator that takes a non-empty sequence and randomly generates one of the values among an initial segment of that sequence. The size of this initial segment increases with the size parameter. Essentially this generator is Gen.elements but taking also the runtime size into account. CompiledName: `GrowingElements`
`listOf(gn)` Signature: gn:Gen<'a> -> Gen<'a list> Type parameters: 'a Attributes: [<CompiledName("ListOf")>]	Generates a list of random length. The maximum length depends on the size parameter. CompiledName: `ListOf`
`listOfLength n arb` Signature: n:int -> arb:Gen<'a18> -> Gen<'a18 list> Type parameters: 'a18 Attributes: [<CompiledName("ListOf")>]	Generates a list of given length, containing values generated by the given generator. CompiledName: `ListOf`
`map f gen` Signature: f:('a -> 'b) -> gen:Gen<'a> -> Gen<'b> Type parameters: 'a, 'b Attributes: [<CompiledName("Map")>]	Apply the function f to the value in the generator, yielding a new generator. CompiledName: `Map`
`map2 f a b` Signature: f:('c -> 'd -> 'e) -> a:Gen<'c> -> b:Gen<'d> -> Gen<'e> Type parameters: 'c, 'd, 'e Attributes: [<CompiledName("Map2")>]	Map the given function over values to a function over generators of those values. CompiledName: `Map2`
`map3 f a b c` Signature: f:('a18 -> 'a19 -> 'a20 -> 'a21) -> a:Gen<'a18> -> b:Gen<'a19> -> c:Gen<'a20> -> Gen<'a21> Type parameters: 'a18, 'a19, 'a20, 'a21 Attributes: [<CompiledName("Map3")>]	Map the given function over values to a function over generators of those values. CompiledName: `Map3`
`map4 f a b c d` Signature: f:('?202663 -> '?202664 -> '?202665 -> '?202666 -> '?202667) -> a:Gen<'?202663> -> b:Gen<'?202664> -> c:Gen<'?202665> -> d:Gen<'?202666> -> Gen<'?202667> Type parameters: '?202663, '?202664, '?202665, '?202666, '?202667 Attributes: [<CompiledName("Map4")>]	Map the given function over values to a function over generators of those values. CompiledName: `Map4`
`map5 f a b c d e` Signature: f:('a18 -> 'a19 -> 'a20 -> 'a21 -> 'a22 -> 'a23) -> a:Gen<'a18> -> b:Gen<'a19> -> c:Gen<'a20> -> d:Gen<'a21> -> e:Gen<'a22> -> Gen<'a23> Type parameters: 'a18, 'a19, 'a20, 'a21, 'a22, 'a23 Attributes: [<CompiledName("Map5")>]	Map the given function over values to a function over generators of those values. CompiledName: `Map5`
`map6 f a b c d e g` Signature: f:('?202678 -> '?202679 -> '?202680 -> '?202681 -> '?202682 -> '?202683 -> '?202684) -> a:Gen<'?202678> -> b:Gen<'?202679> -> c:Gen<'?202680> -> d:Gen<'?202681> -> e:Gen<'?202682> -> g:Gen<'?202683> -> Gen<'?202684> Type parameters: '?202678, '?202679, '?202680, '?202681, '?202682, '?202683, '?202684 Attributes: [<CompiledName("Map6")>]	Map the given function over values to a function over generators of those values. CompiledName: `Map6`
`nonEmptyListOf(gn)` Signature: gn:Gen<'b> -> Gen<'b list> Type parameters: 'b Attributes: [<CompiledName("NonEmptyListOf")>]	Generates a non-empty list of random length. The maximum length depends on the size parameter. CompiledName: `NonEmptyListOf`
`oneof(gens)` Signature: gens:seq<Gen<'a>> -> Gen<'a> Type parameters: 'a Attributes: [<CompiledName("OneOf")>]	Build a generator that generates a value from one of the generators in the given non-empty seq, with equal probability. CompiledName: `OneOf`
`oneOfArr(generators)` Signature: generators:Gen<'?202638> array -> Gen<'?202638> Type parameters: '?202638 Attributes: [<CompiledName("OneOf")>] [<CompilerMessage("This method is not intended for use from F#.", 10001, IsHidden = true, IsError = false)>]	Build a generator that generates a value from one of the given generators, with equal probability. CompiledName: `OneOf`
`optionOf(g)` Signature: g:Gen<'b> -> Gen<'b option> Type parameters: 'b	Generate an option value that is 'None' 1/8 of the time.
`piles k sum` Signature: k:int -> sum:int -> Gen<int []> Attributes: [<CompiledName("Piles")>]	Generates a random array of length k where the sum of all elements equals the given sum. CompiledName: `Piles`
`resize newSize arg2` Signature: newSize:int -> Gen<'b> -> Gen<'b> Type parameters: 'b Attributes: [<CompiledName("Resize")>]	Override the current size of the test. resize n g invokes generator g with size parameter n. CompiledName: `Resize`
`sample size n generator` Signature: size:int -> n:int -> generator:Gen<'b> -> 'b list Type parameters: 'b Attributes: [<CompiledName("Sample")>]	Generates n values of the given size. CompiledName: `Sample`
`sequence(l)` Signature: l:seq<Gen<'a>> -> Gen<'a list> Type parameters: 'a Attributes: [<CompiledName("SequenceToList")>]	Sequence the given enumerable of generators into a generator of a list. CompiledName: `SequenceToList`
`sequenceToArr(generators)` Signature: generators:Gen<'b> array -> Gen<'b []> Type parameters: 'b Attributes: [<CompiledName("Sequence")>]	Sequence the given array of generators into a generator of a array. CompiledName: `Sequence`
`sequenceToSeq(generators)` Signature: generators:seq<Gen<'?202702>> -> Gen<seq<'?202702>> Type parameters: '?202702 Attributes: [<CompiledName("Sequence")>]	Sequence the given enumerable of generators into a generator of an enumerable. CompiledName: `Sequence`
`shuffle(xs)` Signature: xs:seq<'?202710> -> Gen<'?202710 array> Type parameters: '?202710 Attributes: [<CompiledName("Shuffle")>]	Generates a random permutation of the given sequence. CompiledName: `Shuffle`
`sized(fgen)` Signature: fgen:(int -> Gen<'b>) -> Gen<'b> Type parameters: 'b Attributes: [<CompiledName("Sized")>]	Obtain the current size. sized g calls g, passing it the current size as a parameter. CompiledName: `Sized`
`sizedFunc(sizedGen)` Signature: sizedGen:Func<int,Gen<'?202621>> -> Gen<'?202621> Type parameters: '?202621 Attributes: [<CompiledName("Sized")>] [<CompilerMessage("This method is not intended for use from F#.", 10001, IsHidden = true, IsError = false)>]	Obtain the current size. sized g calls g, passing it the current size as a parameter. CompiledName: `Sized`
`subListOf(l)` Signature: l:seq<'?202729> -> Gen<'?202729 list> Type parameters: '?202729 Attributes: [<CompiledName("SubListOfToList")>]	Generates sublists of the given sequence. CompiledName: `SubListOfToList`
`subListOfArr(s)` Signature: s:'?202733 array -> Gen<IList<'?202733>> Type parameters: '?202733 Attributes: [<CompiledName("SubListOf")>] [<CompilerMessage("This method is not intended for use from F#.", 10001, IsHidden = true, IsError = false)>]	Generates sublists of the given arguments. CompiledName: `SubListOf`
`subListOfToIList(s)` Signature: s:seq<'?202731> -> Gen<IList<'?202731>> Type parameters: '?202731 Attributes: [<CompiledName("SubListOf")>] [<CompilerMessage("This method is not intended for use from F#.", 10001, IsHidden = true, IsError = false)>]	Generates sublists of the given IEnumerable. CompiledName: `SubListOf`
`suchThat` Signature: ('?202722 -> bool) -> Gen<'?202722> -> Gen<'?202722> Type parameters: '?202722 Attributes: [<Obsolete("This function will be removed in a future version of FsCheck. Please use the synonyms where or filter instead.")>] [<CompiledName("SuchThat")>]	WARNING: This API is obsolete This function will be removed in a future version of FsCheck. Please use the synonyms where or filter instead. Generates a value that satisfies a predicate. Contrary to suchThatOption, this function keeps re-trying by increasing the size of the original generator ad infinitum. Make sure there is a high probability that the predicate is satisfied. CompiledName: `SuchThat`
`suchThatOption` Signature: ('?202716 -> bool) -> Gen<'?202716> -> Gen<'?202716 option> Type parameters: '?202716 Attributes: [<Obsolete("This function will be removed in a future version of FsCheck. Please use the synonyms tryWhere or tryFilter instead.")>] [<CompiledName("SuchThatOption")>] [<EditorBrowsable(1)>]	WARNING: This API is obsolete This function will be removed in a future version of FsCheck. Please use the synonyms tryWhere or tryFilter instead. Tries to generate a value that satisfies a predicate. This function 'gives up' by generating None if the given original generator did not generate any values that satisfied the predicate, after trying to get values by increasing its size. CompiledName: `SuchThatOption`
`three(g)` Signature: g:Gen<'b> -> Gen<'b * 'b * 'b> Type parameters: 'b Attributes: [<CompiledName("Three")>]	Build a generator that generates a 3-tuple of the values generated by the given generator. CompiledName: `Three`
`tryFilter predicate generator` Signature: predicate:('?202714 -> bool) -> generator:Gen<'?202714> -> Gen<'?202714 option> Type parameters: '?202714 Attributes: [<CompiledName("TryFilter")>]	Tries to generate a value that satisfies a predicate. This function 'gives up' by generating None if the given original generator did not generate any values that satisfied the predicate, after trying to get values by increasing its size. The `tryFilter` function is an alias for the `tryWhere` function. These two functions are identical, but co-exist so that you can choose the word that makes your code most readable in your given context. CompiledName: `TryFilter`
`tryWhere predicate generator` Signature: predicate:('a -> bool) -> generator:Gen<'a> -> Gen<'a option> Type parameters: 'a Attributes: [<CompiledName("TryWhere")>]	Tries to generate a value that satisfies a predicate. This function 'gives up' by generating None if the given original generator did not generate any values that satisfied the predicate, after trying to get values by increasing its size. The `tryWhere` function is also aliased as `tryFilter`. These two functions are identical, but co-exist so that you can choose the word that makes your code most readable in your given context. CompiledName: `TryWhere`
`two(g)` Signature: g:Gen<'a18> -> Gen<'a18 * 'a18> Type parameters: 'a18 Attributes: [<CompiledName("Two")>]	Build a generator that generates a 2-tuple of the values generated by the given generator. CompiledName: `Two`
`unzip(g)` Signature: g:Gen<'?202693 * '?202694> -> Gen<'?202693> * Gen<'?202694> Type parameters: '?202693, '?202694	Split a generator of pairs into a pair of generators.
`unzip3(g)` Signature: g:Gen<'?202696 * '?202697 * '?202698> -> Gen<'?202696> * Gen<'?202697> * Gen<'?202698> Type parameters: '?202696, '?202697, '?202698	Split a generator of 3-tuples into a 3-tuple of generators.
`where predicate generator` Signature: predicate:('b -> bool) -> generator:Gen<'b> -> Gen<'b> Type parameters: 'b Attributes: [<CompiledName("Where")>]	Generates a value that satisfies a predicate. Contrary to tryWhere, this function keeps re-trying by increasing the size of the original generator ad infinitum. Make sure there is a high probability that the predicate is satisfied. The `where` function is also aliased as `filter`. These two functions are identical, but co-exist so that you can choose the word that makes your code most readable in your given context. CompiledName: `Where`
`zip f g` Signature: f:Gen<'c> -> g:Gen<'d> -> Gen<'c * 'd> Type parameters: 'c, 'd	Combine two generators into a generator of pairs.
`zip3 f g h` Signature: f:Gen<'d> -> g:Gen<'e> -> h:Gen<'f> -> Gen<'d * 'e * 'f> Type parameters: 'd, 'e, 'f	Combine three generators into a generator of 3-tuples.