BlackFox.MasterOfFoo
2.1.0
dotnet add package BlackFox.MasterOfFoo --version 2.1.0
NuGet\Install-Package BlackFox.MasterOfFoo -Version 2.1.0
<PackageReference Include="BlackFox.MasterOfFoo" Version="2.1.0" />
paket add BlackFox.MasterOfFoo --version 2.1.0
#r "nuget: BlackFox.MasterOfFoo, 2.1.0"
// Install BlackFox.MasterOfFoo as a Cake Addin #addin nuget:?package=BlackFox.MasterOfFoo&version=2.1.0 // Install BlackFox.MasterOfFoo as a Cake Tool #tool nuget:?package=BlackFox.MasterOfFoo&version=2.1.0
MasterOfFoo
A library to allow using printf
style strings in more places.
The code is essentially an extracted version of printf.fs
where the environement can not only decide
what to do with the final blocks that compose the string (printf put them on the console, sprintf in a buffer, ...)
but also what to do with the parameters passed for each format specifier.
Sample usage
module MyModule =
open System.Text
open BlackFox.MasterOfFoo
type private MySprintfEnv() =
inherit PrintfEnv<unit, string, string>()
let buf = StringBuilder()
override this.Finalize() = buf.ToString ()
override this.Write(s : PrintableElement) = ignore(buf.Append(s.FormatAsPrintF()))
override this.WriteT(s : string) = ignore(buf.Append(s))
let mysprintf (format: Format<'T, unit, string, string>) =
doPrintfFromEnv format (MySprintfEnv())
MyModule.mysprintf "Hello %s." "World"
Mini-Doc
PrintableElement
PrintableElement
represent an element in a string, for example sprintf "Foo %s bar" "x"
produce 3
PrintableElement
, the first contains the string "Foo "
the second is a format specifier 's'
with an associated
string value "x"
and then there is the string the string " Bar"
.
Members :
ElementType
: Tell your if this is a string or a format specifier.Value
: give the value if it was a format specifier.ValueType
: give the type of value expected by the format specifier.StarWidth
: The width if specified via another parameter as in "%*i".StarPrecision
: The precision if specified via another parameter as in "%.*f".FormatAsPrintF()
: Get the string representation that printf would have normally generated.Specifier
: The format specification for format specifiers.
PrintfEnv
PrintfEnv
is the type to implement to create a printf variant it has 3 type parameters:
'State
: The state of the printer, passed as argument when using '%t'.'Residue
: The type that methods passed to '%t' must return.'Result
: The final result type for the printer.
Members:
Finalize
: Create the final result for this printerWrite
: Write an element from the format string to the printerWriteT
: Write the result of the method provided by %t to the printer.
Functions
doPrintfFromEnv
: Take a format and aPrintfEnv
to create a printf-like functiondoPrintf
: Same asdoPrintfFromEnv
but allow to know the number of elements when thePrintfEnv
is created.
FAQ
What does it allow exactly that can't be done with the original set of functions ?
- Generating complex object that aren't only a string like an
SqlCommand
or structured logging. - Escaping parts in strings, like an
xmlprintf
that would escape<
to<
in parameters but not in the format string.
What are the limitations ?
The main limitation is that the F# compiler allow a strict set of things an you can't go differently.
The function signature that is the first argument to Format<_,_,_,_,>
is generated from rules in the compiler and no
library can change them.
The consequence is that we're limited to what is present in the F# compiler, can't add a %Z
or allow %0s
to work.
Aren't you just replicating ksprintf
?
ksprintf
allow you to run code on the final generated result, essentially allowing you to run code during
PrintfEnv.Finalize
but you can't manipualte the format specifiers or their parameters.
What this Star
syntax
When *
is specified for either the width or the precision an additional parameter is taken by the format to get the
value.
> sprintf "%*.*f";;
val it : (int -> int -> float -> string) = <fun:it@1>
How are interpolated strings represented ?
The details of string interpolation internals are specified in F# RFC FS-1001 - String Interpolation.
They appear as follow in this library:
- Type-checked "printf-style" fills behave exactly as they do in
sprintf
and friends. - Unchecked ".NET-style" fills appear with a
Specifier.TypeChar
of'P'
and the .NET format string inSpecifier.InteropHoleDotNetFormat
.
Projects using it
- ColoredPrintf: A small library that I created to add colored parts to printf strings.
If you use it somewhere, ping me on the fediverse @vbfox@hachyderm.io so I can add you.
More fun ?
module ColorPrintf =
open System
open System.Text
open BlackFox.MasterOfFoo
type private Colorize<'Result>(k) =
inherit PrintfEnv<unit, string, 'Result>()
override this.Finalize() : 'Result = k()
override this.Write(s : PrintableElement) =
match s.ElementType with
| PrintableElementType.FromFormatSpecifier ->
let color = Console.ForegroundColor
Console.ForegroundColor <- ConsoleColor.Blue
Console.Write(s.FormatAsPrintF())
Console.ForegroundColor <- color
| _ -> Console.Write(s.FormatAsPrintF())
override this.WriteT(s : string) =
let color = Console.ForegroundColor
Console.ForegroundColor <- ConsoleColor.Red
Console.Write(s)
Console.ForegroundColor <- color
let colorprintf (format: Format<'T, unit, string, unit>) =
doPrintfFromEnv format (Colorize id)
ColorPrintf.colorprintf "%s est %t" "La vie" (fun _ -> "belle !")
Product | Versions Compatible and additional computed target framework versions. |
---|---|
.NET | net5.0 is compatible. net5.0-windows was computed. net6.0 was computed. net6.0-android was computed. net6.0-ios was computed. net6.0-maccatalyst was computed. net6.0-macos was computed. net6.0-tvos was computed. net6.0-windows was computed. net7.0 was computed. net7.0-android was computed. net7.0-ios was computed. net7.0-maccatalyst was computed. net7.0-macos was computed. net7.0-tvos was computed. net7.0-windows was computed. net8.0 was computed. net8.0-android was computed. net8.0-browser was computed. net8.0-ios was computed. net8.0-maccatalyst was computed. net8.0-macos was computed. net8.0-tvos was computed. net8.0-windows was computed. |
.NET Core | netcoreapp2.0 was computed. netcoreapp2.1 was computed. netcoreapp2.2 was computed. netcoreapp3.0 was computed. netcoreapp3.1 was computed. |
.NET Standard | netstandard2.0 is compatible. netstandard2.1 was computed. |
.NET Framework | net461 is compatible. net462 was computed. net463 was computed. net47 was computed. net471 was computed. net472 was computed. net48 was computed. net481 was computed. |
MonoAndroid | monoandroid was computed. |
MonoMac | monomac was computed. |
MonoTouch | monotouch was computed. |
Tizen | tizen40 was computed. tizen60 was computed. |
Xamarin.iOS | xamarinios was computed. |
Xamarin.Mac | xamarinmac was computed. |
Xamarin.TVOS | xamarintvos was computed. |
Xamarin.WatchOS | xamarinwatchos was computed. |
-
.NETFramework 4.6.1
- FSharp.Core (>= 4.5.0)
-
.NETStandard 2.0
- FSharp.Core (>= 4.5.0)
-
net5.0
- No dependencies.
NuGet packages (3)
Showing the top 3 NuGet packages that depend on BlackFox.MasterOfFoo:
Package | Downloads |
---|---|
BlackFox.ColoredPrintf
Provide a printf replacement with colors. This library provide a colorprintf function where colors can be set for a range using the syntax : $foreground;background[text] For example: colorprintf "Hello $red[%s]." "world" |
|
Interstellar.Core
Cross-platform F# browser library |
|
FSharp.Logf
Printf-style logging for structured loggers. |
GitHub repositories
This package is not used by any popular GitHub repositories.
Version | Downloads | Last updated |
---|---|---|
2.1.0 | 331 | 9/6/2024 |
2.0.0 | 207 | 9/5/2024 |
2.0.0-alpha.2 | 50 | 9/5/2024 |
2.0.0-alpha.1 | 56 | 9/5/2024 |
1.0.6 | 7,179 | 4/17/2021 |
1.0.5 | 3,560 | 12/4/2018 |
1.0.4 | 1,232 | 12/4/2018 |
1.0.3 | 1,362 | 9/9/2018 |
1.0.2 | 17,653 | 7/22/2018 |
1.0.1 | 3,308 | 2/11/2018 |
0.2.1 | 1,646 | 4/28/2017 |
0.2.0 | 1,794 | 10/23/2016 |
0.1.2 | 1,889 | 10/7/2016 |
0.1.1 | 1,591 | 10/7/2016 |
Synchronize with the latest FSharp.Core version and support the `%B` format specifier