Extensible printf-style formatting for numbers and other datatypes
Format specifications are strings with "%" markers indicating format
placeholders. Format placeholders consist of:
%[flags][width][.precision][type]
where the type is interpreted as follows:
%b: bool, formatted as "true" or "false"
%s: string, formatted as its unescaped contents
%d, %i: any basic integer type formatted as a decimal integer, signed if the basic integer type is signed.
%u: any basic integer type formatted as an unsigned decimal integer
%x, %X, %o: any basic integer type formatted as an unsigned hexadecimal
(a-f)/Hexadecimal (A-F)/Octal integer
%e, %E, %f, %F, %g, %G:
any basic floating point type (float,float32) formatted
using a C-style floating point format specifications, i.e
%e, %E: Signed value having the form [-]d.dddde[sign]ddd where
d is a single decimal digit, dddd is one or more decimal
digits, ddd is exactly three decimal digits, and sign
is + or -
%f: Signed value having the form [-]dddd.dddd, where dddd is one
or more decimal digits. The number of digits before the
decimal point depends on the magnitude of the number, and
the number of digits after the decimal point depends on
the requested precision.
%g, %G: Signed value printed in f or e format, whichever is
more compact for the given value and precision.
%M: System.Decimal value
%O: Any value, printed by boxing the object and using it's ToString method(s)
%A: Any value, printed by using Microsoft.FSharp.Text.StructuredPrintfImpl.Display.any_to_string with the default layout settings
%a: A general format specifier, requires two arguments:
(1) a function which accepts two arguments:
(a) a context parameter of the appropriate type for the
given formatting function (e.g. an #System.IO.TextWriter)
(b) a value to print
and which either outputs or returns appropriate text.
(2) the particular value to print
%t: A general format specifier, requires one argument:
(1) a function which accepts a context parameter of the
appropriate type for the given formatting function (e.g.
an System.IO.TextWriter)and which either outputs or returns
appropriate text.
Basic integer types are:
byte,sbyte,int16,uint16,int32,uint32,int64,uint64,nativeint,unativeint
Basic floating point types are:
float, float32
The following format patterns are accepted but a warning is printed:
%h(d|u|x|X|o)
%l(d|u|x|X|o)
The following format patterns are now deprecated:
%Ld, %Li, %Lu, %Lx, %LX, %Lo: same, but an int64
%nd, %ni, %nu, %nx, %nX, %no: same, but a nativeint
%Ud, %Ui, %Uu, %Ux, %UX, %Uo: same, but an unsigned int32 (uint32)
%ULd, %ULi, %ULu, %ULx, %ULX, %ULo: same, but an unsigned int64 (uint64)
%Und, %Uni, %Unu, %Unx, %UnX, %Uno: same, but an unsigned nativeint (unativeint)
The optional width is an integer indicating the minimal width of the
result. For instance, %6d prints an integer, prefixing it with spaces
to fill at least 6 characters. If width is '*', then an extra integer
argument is taken to specify the corresponding width.
any number
'*':
Valid flags are:
0: add zeros instead of spaces to make up the required width
'-': left justify the result within the width specified
'+': add a '+' character if the number is positive (to match a '-' sign
for negatives)
' ': add an extra space if the number is positive (to match a '-'
sign for negatives)
The printf '#' flag is invalid and a compile-time error will be reported if it is used.
Type Definitions
| Type | Description |
|---|
| type BuilderFormat |
Represents a statically-analyzed format associated with writing to a System.Text.StringBuilder. The first type parameter indicates the
arguments of the format operation and the last the overall return type.
Note: an abbreviation for Format<'T,StringBuilder,unit,'Result> |
| type BuilderFormat |
Represents a statically-analyzed format associated with writing to a System.Text.StringBuilder. The type parameter indicates the
arguments and return type of the format operation.
Note: an abbreviation for BuilderFormat<'T,unit> |
| type StringFormat |
Represents a statically-analyzed format when formatting builds a string. The first type parameter indicates the
arguments of the format operation and the last the overall return type.
Note: an abbreviation for Format<'T,unit,string,'Result> |
| type StringFormat |
Represents a statically-analyzed format when formatting builds a string. The type parameter indicates the
arguments and return type of the format operation.
Note: an abbreviation for StringFormat<'T,string> |
| type TextWriterFormat |
Represents a statically-analyzed format associated with writing to a System.IO.TextWriter. The first type parameter indicates the
arguments of the format operation and the last the overall return type.
Note: an abbreviation for Format<'T,TextWriter,unit,'Result> |
| type TextWriterFormat |
Represents a statically-analyzed format associated with writing to a System.IO.TextWriter. The type parameter indicates the
arguments and return type of the format operation.
Note: an abbreviation for TextWriterFormat<'T,unit> |
Values
| Value | Description |
|---|
val bprintf : StringBuilder -> BuilderFormat<'T> -> 'T |
Print to a System.Text.StringBuilder
|
val eprintf : TextWriterFormat<'T> -> 'T |
Formatted printing to stderr
|
val eprintfn : TextWriterFormat<'T> -> 'T |
Formatted printing to stderr, adding a newline
|
val failwithf : StringFormat<'T,'Result> -> 'T |
Print to a string buffer and raise an exception with the given
result. Helper printers must return strings.
|
val fprintf : TextWriter -> TextWriterFormat<'T> -> 'T |
Print to a text writer or an OCaml-compatible channel
|
val fprintfn : TextWriter -> TextWriterFormat<'T> -> 'T |
Print to a text writer or an OCaml-compatible channel, adding a newline
|
val kbprintf :
(unit -> 'Result) -> StringBuilder -> BuilderFormat<'T,'Result> -> 'T |
bprintf, but call the given 'final' function to generate the result.
See kprintf.
|
val kfprintf :
(unit -> 'Result) -> TextWriter -> TextWriterFormat<'T,'Result> -> 'T |
fprintf, but call the given 'final' function to generate the result.
See kprintf.
|
val kprintf : (string -> 'Result) -> StringFormat<'T,'Result> -> 'T |
printf, but call the given 'final' function to generate the result.
For example, these let the printing force a flush after all output has
been entered onto the channel, but not before.
|
val ksprintf : (string -> 'Result) -> StringFormat<'T,'Result> -> 'T |
sprintf, but call the given 'final' function to generate the result.
See kprintf.
|
val ktwprintf :
(unit -> 'Result) -> TextWriter -> TextWriterFormat<'T,'Result> -> 'T |
twprintf, but call the given 'final' function to generate the result.
See kprintf.
|
val printf : TextWriterFormat<'T> -> 'T |
Formatted printing to stdout
|
val printfn : TextWriterFormat<'T> -> 'T |
Formatted printing to stdout, adding a newline
|
val sprintf : StringFormat<'T> -> 'T |
Print to a string via an internal string buffer and return
the result as a string. Helper printers must return strings.
|
val twprintf : TextWriter -> TextWriterFormat<'T> -> 'T |
Print to any subtype of the .NET type System.IO.TextWriter
|
val twprintfn : TextWriter -> TextWriterFormat<'T> -> 'T |
Print to any subtype of the .NET type System.IO.TextWriter, and add a newline
|
|