Enable command line arguments when compiling with juliac

juliac/runicc.jl

@@ -2,10 +2,21 @@ module RunicC
 
 using Runic: Runic
 
-# TODO: Why do we need this shim? Wouldn't it be possible to just compile `src/Runic.jl`?
-Base.@ccallable function main()::Cint
-    argv = String[]
-    return Runic.main(argv)
+# Compileable main function corresponding to `int main(int argc, char** argv)`
+Base.@ccallable function main(argc::Cint, argv::Ptr{Ptr{UInt8}})::Cint
+    # Load command line arguments. Note that the first argument is the
+    # executable name so we skip it.
+    args = Vector{String}(undef, argc - 1)
+    for i in 2:argc
+        argptr = unsafe_load(argv, i)
+        arg = unsafe_string(argptr)
+        args[i - 1] = arg
+    end
+    # Call Runic's main function
+    return Runic.main(args)
 end
 
+# Tell juliac about the main entrypoint
+Base.Experimental.entrypoint(main, (Cint, Ptr{Ptr{UInt8}}))
+
 end