linux-packaging-fsharp/Language-Version-History.md

Features Added in F# Language Versions

F# 4.7

• Compiler support for LangVersion
• Implicit yields
• No more required double underscore (wildcard identifier)
• Indentation relaxations for parameters passed to constructors and static methods

F# 4.6

• Anonymous records
• ValueOption module functions

F# 4.5

• Versioning alignment of binary, package, and language
• Support for Span<'T> and related types
• Ability to produce byref returns
• The voidptr type
• The inref<'T> and outref<'T> types to represent readonly and write-only byrefs
• IsByRefLike structs
• IsReadOnly structs
• Extension method support for byref<'T>/inref<'T>/outref<'T>
• match! keyword in computation expressions
• Relaxed upcast with yield in F# sequence/list/array expressions
• Relaxed indentation with list and array expressions
• Enumeration cases emitted as public

F# 4.1

• Struct tuples which inter-operate with C# tuples
• Struct annotations for Records
• Struct annotations for Single-case Discriminated Unions
• Underscores in numeric literals
• Caller info argument attributes
• Result type and some basic Result functions
• Mutually referential types and modules within the same file
• Implicit Module syntax on modules with shared name as type
• Byref returns, supporting consuming C# ref-returning methods
• Error message improvements
• Support for fixed

F# 4.0

• printf on unitized values
• Extension property initializers
• Non-null provided types
• Primary constructors as functions
• Static parameters for provided methods
• printf interpolation
• Extended #if grammar
• Multiple interface instantiations
• Optional type args
• Params dictionaries

F# 3.1

• Named union type fields
• Extensions to array slicing
• Type inference enhancements

F# 3.0

• Type providers
• LINQ query expressions
• CLIMutable attribute
• Triple-quoted strings
• Auto-properties
• Provided units-of-measure

F# 2.0

• Active patterns
• Units of measure
• Sequence expressions
• Asynchronous programming
• Agent programming
• Extension members
• Named arguments
• Optional arguments
• Array slicing
• Quotations
• Native interoperability
• Computation expressions

F# 1.1

• Interactive environment
• Object programming
• Encapsulation Extensions

F# 1.0

• Discriminated unions
• Records
• Tuples
• Pattern matching
• Type abbreviations
• Object expressions
• Structs
• Signature files
• Imperative programming
• Modules (no functors)
• Nested modules
• .NET Interoperability