switch to using Wolfram app discovery

.github/workflows/CI.yml

@@ -20,6 +20,8 @@ jobs:
       - uses: julia-actions/cache@v1
       - uses: julia-actions/julia-buildpkg@v1
       - uses: julia-actions/julia-runtest@v1
+        env:
+          JULIA_DEBUG: MathLink
       - uses: julia-actions/julia-processcoverage@v1
       - uses: codecov/codecov-action@v1
         with:
@@ -40,11 +42,17 @@ jobs:
           echo 'Installing Wolfram Engine...'
           brew install --cask wolfram-engine
           echo 'Installed Wolfram Engine.'
-
+      
       - uses: julia-actions/setup-julia@v1
       - uses: julia-actions/cache@v1
       - uses: julia-actions/julia-buildpkg@v1
+      - run: mdfind "kMDItemCFBundleIdentifier == 'com.wolfram.*'"
+      - run: mdls "/Applications/Wolfram Engine.app"
+      - run: julia --project -e 'using WolframAppDiscovery_jll; run(`$(wolfram_app_discovery()) default`)'
       - uses: julia-actions/julia-runtest@v1
+        env:
+          JULIA_DEBUG: MathLink
+          RUST_BACKTRACE: full
       - uses: julia-actions/julia-processcoverage@v1
       - uses: codecov/codecov-action@v1
         with:
@@ -102,9 +110,10 @@ jobs:
       - uses: julia-actions/setup-julia@v1
       - uses: julia-actions/cache@v1
       - uses: julia-actions/julia-buildpkg@v1
-        env:
-          JULIA_WOLFRAM_DIR: '${{ runner.temp }}\${{ env.WOLFRAMENGINE_INSTALLATION_SUBDIRECTORY }}'
       - uses: julia-actions/julia-runtest@v1
+        env:
+          JULIA_DEBUG: MathLink
+          WOLFRAM_APP_DIRECTORY: '${{ runner.temp }}\${{ env.WOLFRAMENGINE_INSTALLATION_SUBDIRECTORY }}'
       - uses: julia-actions/julia-processcoverage@v1
       - uses: codecov/codecov-action@v1
         with:

Project.toml

@@ -5,6 +5,7 @@ version = "0.5.1"
 [deps]
 Libdl = "8f399da3-3557-5675-b5ff-fb832c97cbdb"
 Printf = "de0858da-6303-5e67-8744-51eddeeeb8d7"
+WolframAppDiscovery_jll = "630c5959-bfb3-598a-bb45-cbcabe526631"
 
 [compat]
 julia = "1"

README.md

@@ -6,9 +6,9 @@ This package provides access to Mathematica/Wolfram Engine via the MathLink libr
 
 ## Installation
 
-The package requires an installation of either [Mathematica](http://www.wolfram.com/mathematica/) or the free [Wolfram Engine](https://www.wolfram.com/engine/). It will attempt to find the installation at build time; if this fails, please see the [installation troubleshoot](#installation-troubleshoot) below.
- 
- 
+The package requires an installation of either [Mathematica](http://www.wolfram.com/mathematica/) or the free [Wolfram Engine](https://www.wolfram.com/engine/). It will attempt to find the installation at load time using [wolfram-app-discovery](https://github.com/WolframResearch/wolfram-app-discovery-rs). A precise location can be specied by setting the `WOLFRAM_APP_DIRECTORY` environment variable.
+
+
 ## Usage
 
 The main interface consists of the `W""` string macro for specifying symbols. These are call-overloaded for building more complicated expressions. 
@@ -166,42 +166,6 @@ julia> W2Mstr(W`b/(c^(a+c))`)
 Printing in Jupyter notebooks is, by default, done in latex.
 This can be turned off with the command `MathLink.set_texOutput(false)`
 
-## Installation Troubleshoot
-The package requires an installation of either [Mathematica](http://www.wolfram.com/mathematica/) or the free [Wolfram Engine](https://www.wolfram.com/engine/). It will attempt to find the installation at build time; if this fails, you will need to set the following environment variables:
-- `JULIA_MATHKERNEL`: the path of the MathKernel executable
-- `JULIA_MATHLINK`: the path of the MathLink dynamic library named
-  - `libML64i4.so`/ `libML32i4.so` on Linux
-  - `ml64i4.dll`/`ml32i4.dll`/`libML64.dll`/ `libML32.dll` on Windows
-
-After setting, you may need to manually build the package
-```julia
-(@v1.X) pkg> build MathLink
-```
-
-A separate workaround is to directly edit the deps/deps.jl file, which should be located (on Linux) at `~/.julia/packages/MathLink/<version dependent>/deps/deps.jl`
-
-The contents of `deps.jl` could for instance, read
-```julia
-const mlib = "/usr/local/Wolfram/Mathematica/11.3/SystemFiles/Links/MathLink/DeveloperKit/Linux-x86-64/CompilerAdditions/libML64i4"
-const mker = "WolframKernel"
-```
-After creating the file `deps.jl` try loading MathLink the usual way
-```julia
-(@v1.X) pkg> using MathLink
-```
-If you do not have a Mathematica installation at all, the above trick still works, but then you must leave the path blank 
-```julia
-const mlib = ""
-const mker = "WolframKernel"
-```
-Loading `MathLink` then proclaims
-```julia
-julia> using MathLink
-[ Info: Precompiling MathLink [18c93696-a329-5786-9845-8443133fa0b4]
-[ Info: Pretending fake installation works
-```
-
-
 ## Notes
 
 - Mathematica, Wolfram, MathLink are all trademarks of Wolfram Research.

src/MathLink.jl

@@ -4,22 +4,14 @@ using Printf
 
 export @W_str, @W_cmd, weval
 
+using WolframAppDiscovery_jll
 
-###Checking that the deps.jl file exists. And throwing a readable error if it does not!
-
-FilePath=@__DIR__
-FilePath=FilePath[1:end-4]*"/deps/deps.jl"
-
-
-#if isfile("../deps/deps.jl")
-    #include("../deps/deps.jl")
-if isfile(FilePath)
-    include(FilePath)
+if VERSION >= v"1.8"
+    libwstp::String = ""
 else
-    error("The file $FilePath does not exist.\n"
-          *"This usually means that the MathLink installation failed.\n"
-          *"Have you checked that Mathematica is installed on your system?")
+    libwstp = ""
 end
+
 include("types.jl")
 include("consts.jl")
 include("init.jl")

src/init.jl

@@ -29,20 +29,34 @@ function refcount_dec()
     # refcount zero, all objects finalized, now finalize MathLink
     if Threads.atomic_sub!(REFCOUNT, 1) == 1
         # void WSDeinitialize(WSENV env)
-        ccall((:MLDeinitialize, mlib), Cvoid, (CEnv,), env)
+        ccall((:WSDeinitialize, libwstp), Cvoid, (CEnv,), env)
         env.ptr = C_NULL
     end
 end
 
+
 function __init__()
-    if mlib == ""
-        ###when JULIA_REGISTRYCI_AUTOMERGE=true the mlib is an empty string, and we can test for that
-        # We need to be able to install and load this package without error for
-        # Julia's registry AutoMerge to work. Skip initialization of the mathlink library.
-        @info "Pretending fake installation works"
-    else
+
+    out = IOBuffer()
+    if !success(pipeline(`$(wolfram_app_discovery()) default --raw-value wstp-compiler-additions-directory`, out))
+        @debug "Could not find WSTP installation"
+        return
+    end
+    wstp_dir = String(take!(out))
+
+    if Sys.iswindows()
+        global libwstp = joinpath(wstp_dir, "..", "SystemAdditions", "wstp$(Sys.WORD_SIZE)i4.dll")
+    elseif Sys.isapple()
+        global libwstp = joinpath(wstp_dir, "wstp.framework", "wstp")
+    elseif Sys.isunix()
+        global libwstp = joinpath(wstp_dir, "libWSTP$(Sys.WORD_SIZE)i4.so")
+    end
+
+    @debug "WSTP installation found" wstp_dir libwstp
+
+    if libwstp != ""
         # WSENV WSInitialize(WSEnvironmentParameter p) 
-        env.ptr = ccall((:MLInitialize, mlib), CEnv, (Ptr{Cvoid},), C_NULL)
+        env.ptr = ccall((:WSInitialize, libwstp), CEnv, (Ptr{Cvoid},), C_NULL)
         if env.ptr == C_NULL
             error("Could not initialize MathLink library")
         end