NickelEval.jl

commit 0139f5f82a9fe335d165b8211549a7c30fc992a6
parent 2251a68997c0e59c5662acdf875a6df5240d9d7c
Author: Erik Loualiche <eloualiche@users.noreply.github.com>
Date:   Wed, 18 Mar 2026 13:51:58 -0400

Merge pull request #11 from LouLouLibs/fix/graceful-dlopen

Graceful dlopen fallback + build_ffi() function
Diffstat:
M
src/NickelEval.jl
 | 
2
+-
M
src/ffi.jl
 | 
37
+++++++++++++++++++++++++++++++------

2 files changed, 32 insertions(+), 7 deletions(-)
diff --git a/src/NickelEval.jl b/src/NickelEval.jl
@@ -2,7 +2,7 @@ module NickelEval
 
 export nickel_eval, nickel_eval_file, @ncl_str, NickelError, NickelEnum
 export nickel_to_json, nickel_to_yaml, nickel_to_toml
-export check_ffi_available
+export check_ffi_available, build_ffi
 
 """
     NickelError <: Exception
diff --git a/src/ffi.jl b/src/ffi.jl
@@ -44,9 +44,14 @@ FFI_AVAILABLE::Bool = false
 function __init_ffi__()
     path = _find_library_path()
     if path !== nothing
-        global libnickel_lang = path
-        global FFI_AVAILABLE = true
-        Libdl.dlopen(path)
+        try
+            Libdl.dlopen(path)
+            global libnickel_lang = path
+            global FFI_AVAILABLE = true
+        catch e
+            @warn "Found libnickel_lang at $path but failed to load it: $e\n" *
+                  "Build from source with: build_ffi()"
+        end
     end
 end
 
@@ -61,12 +66,32 @@ Check if the Nickel C API library is available.
 """
 check_ffi_available() = FFI_AVAILABLE
 
+"""
+    build_ffi()
+
+Build the Nickel C API library from source. Requires Rust (cargo).
+Restarts the FFI after building so you don't need to restart Julia.
+"""
+function build_ffi()
+    build_script = joinpath(@__DIR__, "..", "deps", "build.jl")
+    @info "Building Nickel C API library from source..."
+    withenv("NICKELEVAL_BUILD_FFI" => "true") do
+        include(build_script)
+    end
+    # Re-initialize to pick up the newly built library
+    __init_ffi__()
+    if FFI_AVAILABLE
+        @info "FFI ready. nickel_eval() is now available."
+    else
+        error("Build completed but library still not loadable. Check the build output above.")
+    end
+end
+
 function _check_ffi_available()
     FFI_AVAILABLE && return
     error("Nickel C API library not available.\n\n" *
-          "Install options:\n" *
-          "  1. Build from source: NICKELEVAL_BUILD_FFI=true julia -e 'using Pkg; Pkg.build(\"NickelEval\")'\n" *
-          "  2. Place $(LIB_NAME) in deps/ manually\n")
+          "Build from Julia:  using NickelEval; build_ffi()\n" *
+          "Build from shell:  NICKELEVAL_BUILD_FFI=true julia -e 'using Pkg; Pkg.build(\"NickelEval\")'\n")
 end
 
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