F# comes with a number of essential basic functions and operators pre-defined. For example, even “+” is an operator defined in Microsoft.FSharp.Core.Operators, which is opened by default. Likewise “abs” is a function to take the absolute value of a signed integer or floating point number, and “int64” is a function that converts its input to a 64-bit signed integer.
In this post I’ve listed the most important of the pre-defined operators. These operators are also now listed in the F# manual, Chapter 16. Importantly, many of these operators use a form of statically resolved, extensible overloading in the form of F# member constraints. That is, a function such as “int64” (convert to int64) can be used with any type that has a static ToInt64 member with an appropriate signature. The relevant corresponding member name is shown in F# intellisense in Visual Studio and may appear in error messages, and the full required signature is specified in prim-types.fsi in the F# distribution. F# simulates the presence of certain methods on basic types to ensure consistency and uniformity in the overloading scheme.
Note that some functions have beeen added in the CTP release and may be unfamiliar to existing users, e.g. pown. Also, some functions an operators are given special types when applied to floating point (float, float32 or decimal) arguments with unit-of-measure annotations.
Basic Type Abbreviations
Type Name |
Short Description |
obj |
System.Object |
exn |
System.Exception |
nativeint |
System.IntPtr |
unativeint |
System.UIntPtr |
string |
System.String |
float32, single |
System.Single |
float, double |
System.Double |
sbyte |
System.SByte |
byte |
System.Byte |
int16 |
System.Int16 |
uint16 |
System.UInt16 |
int32, int |
System.Int32 |
uint32 |
System.UInt32 |
int64 |
System.Int64 |
uint64 |
System.UInt64 |
char |
System.Char |
bool |
System.Boolean |
decimal |
System.Decimal |
Basic Arithmetic Operators
The following operators are defined in Microsoft.FSharp.Core.Operators:
Operator/Function Name |
Expression Form |
Short Description |
(+) |
x + y |
Overloaded addition |
(-) |
x – y |
Overloaded subtraction |
(*) |
x * y |
Overloaded multiplication |
(/) |
x / y |
Overloaded division |
(%) |
x % y |
Overloaded modulus |
(~-) |
-x |
Overloaded unary negation |
not |
not x |
Boolean negation |
Generic Equality and Comparison Operators
The following operators are defined in Microsoft.FSharp.Core.Operators:
Operator/Function Name |
Expression Form |
Short Description |
(<) |
x < y |
Generic less-than |
(<=) |
x <= y |
Generic less-than-or-equal |
(>) |
x > y |
Generic greater-than |
(>=) |
x >= y |
Generic greater-than-or-equal |
(=) |
x = y |
Generic equality |
(<>) |
x <> y |
Generic disequality |
max |
max x y |
Generic maximum |
min |
min x y |
Generic minimum |
Bitwise manipulation operators
The following operators are defined in Microsoft.FSharp.Core.Operators:
Operator/Function Name |
Expression Form |
Short Description |
(<<<) |
x <<< y |
Overloaded bitwise shift-left |
(>>>) |
x >>> y |
Overloaded bitwise arithmetic shift-right |
(^^^) |
x ^^^ y |
Overloaded bitwise exclusive or |
(&&&) |
x &&& y |
Overloaded bitwise and |
(|||) |
x ||| y |
Overloaded bitwise or |
(~~~) |
~~~x |
Overloaded bitwise negation |
Math operators
The following operators are defined in Microsoft.FSharp.Core.Operators:
Operator/Function Name |
Expression Form |
Short Description |
abs |
abs x |
Overloaded absolute value |
acos |
acos x |
Overloaded inverse cosine |
asin |
asin x |
Overloaded inverse sine |
atan |
atan x |
Overloaded inverse tangent |
atan2 |
atan2 x y |
Overloaded inverse tangent of x/y |
ceil |
ceil x |
Overloaded floating point ceiling |
cos |
cos x |
Overloaded cosine |
cosh |
cosh x |
Overloaded hyperbolic cosine |
exp |
exp x |
Overloaded exponent |
floor |
floor x |
Overloaded floating point floor |
log |
log x |
Overloaded natural logarithm |
log10 |
log10 x |
Overloaded base-10 logarithm |
(**) |
x ** y |
Overloaded exponential |
pown |
pown x y |
Overloaded integer exponential |
round |
round x |
Overloaded rounding |
sign |
sign x |
Overloaded sign function |
sin |
sin x |
Overloaded sine function |
sinh |
sinh x |
Overloaded hyperbolic sine function |
sqrt |
sqrt x |
Overloaded square root function |
tan |
tan x |
Overloaded tangent function |
tanh |
tanh x |
Overloaded hyperbolic tangent function |
Function Pipelining and Composition Operators
The following operators are defined in Microsoft.FSharp.Core.Operators:
Operator/Function Name |
Expression Form |
Short Description |
(|>) |
x |> f |
Pipelining |
(>>) |
f >> g |
Function composition |
(<|) |
f <| x |
Backward pipelining |
(<<) |
g << f |
Backward function composition |
ignore |
ignore x |
Compute and discard a value |
Object Transformation Operators
The following operators are defined in Microsoft.FSharp.Core.Operators:
Operator/Function Name |
Expression Form |
Short Description |
box |
box x |
Convert to object representation |
hash |
hash x |
Generic hashing operator |
sizeof |
sizeof<type> |
Compute the size of a value of the given type |
typeof |
typeof<type> |
Compute the System.Type representation of the given type |
typedefof |
typedefof<type> |
Compute the System.Type representation of the given type and calls GetGenericTypeDefinition if this is a generic type. |
unbox |
unbox x |
Convert form object representation |
ref |
ref x |
Allocate a mutable reference cell |
(!) |
!x |
Read a mutable reference cell |
Pair Operators
The following operators are defined in Microsoft.FSharp.Core.Operators:
Operator/Function Name |
Expression Form |
Short Description |
fst |
fst p |
Take the first element of a pair |
snd |
snd p |
Take the second element of a pair |
Exception Operators
The following operators are defined in Microsoft.FSharp.Core.Operators:
Operator/Function Name |
Expression Form |
Short Description |
failwith |
failwith x |
Raise a FailureException exception |
invalid_arg |
invalid_arg x |
Raise an ArgumentException exception |
raise |
raise x |
Raise an exception |
rethrow |
rethrow() |
Special operator to raise an exception |
Input/Output Handles
The following operators are defined in Microsoft.FSharp.Core.Operators:
Operator/Function Name |
Expression Form |
Short Description |
stdin |
stdin |
Computes System.Console.In |
stdout |
stdout |
Computes System.Console.Out |
stderr |
stderr |
Computes System.Console.Error |
Overloaded Conversion Functions
The following operators are defined in Microsoft.FSharp.Core.Operators:
Operator/Function Name |
Expression Form |
Short Description |
byte |
byte x |
Overloaded conversion to a byte |
sbyte |
sbyte x |
Overloaded conversion to a signed byte |
int16 |
int16 x |
Overloaded conversion to a 16 bit integer |
uint16 |
uint16 x |
Overloaded conversion to an unsigned 16 bit integer |
int32, int |
int32 x int x |
Overloaded conversion to a 32 bit integer |
uint32 |
uint32 x |
Overloaded conversion to an unsigned 32 bit integer |
int64 |
int64 x |
Overloaded conversion to a 64 bit integer |
uint64 |
uint64 x |
Overloaded conversion to an unsigned 64 bit integer |
nativeint |
nativeint x |
Overloaded conversion to an native integer |
unativeint |
unativeint x |
Overloaded conversion to an unsigned native integer |
float, double |
float x double x |
Overloaded conversion to a 64-bit IEEE floating point number |
float32, single |
float32 x single x |
Overloaded conversion to a 32-bit IEEE floating point number |
decimal |
decimal x |
Overloaded conversion to a System.Decimal number |
char |
char x |
Overloaded conversion to a System.Char value |
enum |
enum x |
Overloaded conversion to a typed enumeration value |
Checked Arithmetic Operators
The module Microsoft.FSharp.Core.Operators.Checked defines runtime-overflow-checked versions of the following operators:
Operator/Function Name |
Expression Form |
Short Description |
(+) |
x + y |
Checked overloaded addition |
(-) |
x – y |
Checked overloaded subtraction |
(*) |
x * y |
Checked overloaded multiplication |
(~-) |
-x |
Checked overloaded unary negation |
byte |
byte x |
Checked overloaded conversion to a byte |
sbyte |
sbyte x |
Checked overloaded conversion to a signed byte |
int16 |
int16 x |
Checked overloaded conversion to a 16 bit integer |
uint16 |
uint16 x |
Checked overloaded conversion to an unsigned 16 bit integer |
int32, int |
int32 x int x |
Checked overloaded conversion to a 32 bit integer |
uint32 |
uint32 x |
Checked overloaded conversion to an unsigned 32 bit integer |
int64 |
int64 x |
Checked overloaded converstion to a 64 bit integer |
uint64 |
uint64 x |
Checked overloaded conversion to an unsigned 64 bit integer |
nativeint |
nativeint x |
Checked overloaded conversion to an native integer |
unativeint |
unativeint x |
Checked overloaded conversion to an unsigned native integer |
char |
char x |
Checked overloaded conversion to a System.Char value |
Great overview, which is in my opinion a bit more accesible than the overview in the documentation.
I caught a typo up above in row unbox:
"Convert form object representation". If these were copy/pasted from elsewhere, please correct.
This is great work. Are ther points
in FSharp?
I would like to know more about F#
such as how could i learn this language
how soon will manuals be available?
Have people started to use this yet?  I was just introduced to it and think it has a lot of potential