How to call/invoke fsc, the F# compiler, from FAKE? - f#

Question

How do I tell FAKE to compile a .fs file using fsc?
Bonus points for explaining how to also pass arguments like -a and -target:dll.
EDIT: I should clarify that I'm trying to do this without having an MSBuild/xbuild/.sln file. In other words, I want FAKE to fully take the place of MSBuild/xbuild.

Answer 1

FAKE has tasks to directly invoke the F# compiler. Usually you can use the Fsc task. If you want a target to compile an F# source file MyFile.fs to MyFile.exe, you can do:
Target "MyFile.exe" (fun _ ->
["MyFile.fs"]
|> Fsc (fun ps -> ps))
The Fsc task lets you compile multiple source files and specify every F# compile parameter. This simple example doesn't do that, but you can. To read up on the details, head over to the tutorial.

Answer 2

I recommend you read Ian Battersby's page on FAKE make on this topic
Code Excerpt:
first:
#!/bin/bash
TARGET=$1
BUILDTARGETS=$2
if [ -z "$BUILDTARGETS" ]
then
BUILDTARGETS="/Library/Frameworks/Mono.framework/Libraries/mono/xbuild/Microsoft/VisualStudio/v9.0"
fi
if [ -z "$TARGET" ]
then
CTARGET="Default"
else
CTARGET=`echo ${TARGET:0:1} | tr "[:lower:]" "[:upper:]"``echo ${TARGET:1} | tr "[:upper:]" "[:lower:]"`
fi
if [ ! -d "$BUILDTARGETS" ]
then
echo "BuildTargets directory '${BUILDTARGETS}' does not exist."
exit $?
else
export BUILDTARGETS="$BUILDTARGETS"
fi
echo "Executing command: $CTARGET"
mono packages/FAKE.1.64.6/tools/Fake.exe build.fsx target=$CTARGET
then
#I #"packages/FAKE.1.64.6/tools"
#r "FakeLib.dll"
open Fake
let buildDir = #"./build/"
let testDir = #"./test"
let fxReferences = !! #"*/*.csproj"
let testReferences = !! #"Tests/**/*.csproj"
let buildTargets = environVarOrDefault "BUILDTARGETS" ""
Target "Clean" (fun _ ->
CleanDirs [buildDir; testDir]
)
Target "Build" (fun _ ->
MSBuild buildDir "Build" ["Configuration","Debug"; "VSToolsPath",buildTargets] fxReferences
|> Log "Build-Output: "
)
Target "BuildTest" (fun _ ->
MSBuildRelease testDir "Build" testReferences
|> Log "Test-Output: "
)
Target "Test" (fun _ ->
!! (testDir + #"/*.Tests.dll")
|> xUnit (fun p ->
{ p with
ShadowCopy = true;
HtmlOutput = true;
XmlOutput = true;
OutputDir = testDir })
)
"Clean"
==> "Build"
"Build"
==> "BuildTest"
Target "Default" DoNothing
RunParameterTargetOrDefault "target" "Default"

Answer 3

Here's a possibly-useful -- though admittedly small -- twist on Yawar's answer above, which might make it fit in a bit better with the other FAKE examples you're likely to encounter.
The Fsc helper function wants a string list of filenames, which is fine as far as it goes. But most examples use the !! operator to find files, which results in FileIncludes which happens not to be a string list. You can convert a FileIncludes to a string list suitable for feeding to Fsc with Seq.toList.
Just to be thorough, I also convert things to relative pathnames (possibly just a personal quirk).
So here's an example of searching for all *.fs files and compiling them with some representative compiler options:
Target "BuildApp" (fun _ -> // Compile application source code
!! (srcApp ## #"**/*.fs") // Look for F# source files
|> Seq.map toRelativePath // Pathnames relative to current directory
|> Seq.toList // Convert FileIncludes to string list
|> Fsc (fun p -> // which is what the Fsc task wants
{p with // Fsc parameters: making an executable,
FscTarget = Exe // for any CPU, directing output to build
Platform = AnyCpu // area (both assembly & XML doc).
Output = ...exe file... // Executable generated
OtherParams = ["--doc:" + ...xmldoc file...) ]})
) //
As Yawar pointed out, there are a boatload of other compiler options covered in the tutorial.