fflat 2.0.5

fflat - F# native script compiler on bflat

<img alt="Nuget" src="https://img.shields.io/nuget/v/fflat">

Build 1MB native executables from .fsx scripts!

Installation

dotnet tool install --global fflat

Basic usage

fflat script.fsx             # about 1.4M, no debug/globalization/symbols
fflat script.fsx --small     # about 1MB, no reflection/exceptions, no printfn!

run fflat --help for a list of options

Advanced usage

arm64 executable

fflat script.fsx --small build --arch arm64 # 1.2MB and runs on raspberry pi! 👍

using fflat to as an interface to the F# compiler

fflat ./mylibrary.fsx build-il --watch ## quickly recompiles mylibrary.dll on every change 

bflat arguments are specified after build

fflat ./helloworld.fsx --small build -x -r "mylibrary.dll" --os windows ## ... etc

Shared library (experimental)

fflat script.fsx [--small] build-shared

all options

MAIN:

    <script>              .fsx script file path (first argument)

SUBCOMMANDS:

    build <options>       compile to native with bflat [default]
    build-il <options>    compile to IL (using fsc)
    build-shared <options>
                          compile to shared library

    Use 'fflat <subcommand> --help' for additional information.

OPTIONS:

    --verbose, -v         verbose output
    --version             version of application
    --ldflags <string>    <ldflags>
    --noreflection        disable reflection
    --arch <unknown|arm|arm64|x64|x86|wasm32|loongarch64>
                          <x64|arm64>
    --os <unknown|windows|linux|uefi>
                          <linux|windows|uefi>
    --optimize <none|prefersize|blended|preferspeed>
                          <preferspeed|prefersize>
    --tiny, -t            smallest possible executable. NB! avoid using printfn with this
    --small, -s           small executable but retains reflection, stack trace and exception
                          messages
    --output, -o <outputFile>
                          output executable path
    --help                display this list of options.

Common questions, troubleshooting

Why?

there is almost a 1000x difference in startup time for dotnet fsi scripts using nuget!

there is also FSharpPacker for .fsx scripts, which compiles .fsx scripts to native executables using the standard MSBuild pipeline (PublishAOT), but bflat can produce significantly smaller executables or even omit the .NET runtime/GC all together.

TypeInitialization_Type_NoTypeAvailable errors

use --small instead of --tiny, --tiny will crash if your script uses any reflection features.

there's many untrimmable features in the F# core library like printfn, quotations and linq. substituting all printfn calls with stdout.WriteLine will produce significantly smaller binaries as well.

Have fun!