Add replace_global! helper (#930)

src/globals.jl

@@ -55,6 +55,13 @@ end
 
 propertynames(::GlobalsType, private::Bool=false) = Vector{Symbol}(Globals.NamesGVars())
 
+function replace_global!(name::Symbol, val::Any)
+    n = GapObj(name)
+    Wrappers.MakeReadWriteGlobal(n)
+    setproperty!(Globals, name, val)
+    Wrappers.MakeReadOnlyGlobal(n)
+end
+
 @static if VERSION < v"1.10-DEV"
   # HACK to get tab completion to work for GAP globals accessed via GAP.Globals;
   # e.g. if the REPL already shows `GAP.Globals.MTX.Is` and the user presses

src/packages.jl

@@ -2,7 +2,7 @@
 module Packages
 
 using Downloads
-import ...GAP: Globals, GapObj, RNamObj, sysinfo, Wrappers
+import ...GAP: Globals, GapObj, replace_global!, RNamObj, sysinfo, Wrappers
 
 const DEFAULT_PKGDIR = Ref{String}()
 
@@ -17,16 +17,14 @@ function init_packagemanager()
     global DEFAULT_PKGDIR[] = sysinfo["DEFAULT_PKGDIR"]
 
     # overwrite PKGMAN_DownloadURL
-    Globals.MakeReadWriteGlobal(GapObj("PKGMAN_DownloadURL"))
-    Globals.PKGMAN_DownloadURL = function(url)
+    replace_global!(:PKGMAN_DownloadURL, function(url)
       try
         buffer = Downloads.download(String(url), IOBuffer())
         return GapObj(Dict{Symbol, Any}(:success => true, :result => String(take!(buffer))), recursive=true)
       catch
         return GapObj(Dict{Symbol, Any}(:success => false), recursive=true)
       end
-    end
-    Wrappers.MakeReadOnlyGlobal(GapObj("PKGMAN_DownloadURL"))
+    end)
 
     # Install a method (based on Julia's Downloads package) as the first choice
     # for the `Download` function from GAP's utils package,

src/prompt.jl

@@ -22,9 +22,7 @@ function prompt()
 
     # restore GAP's error output
     disable_error_handler[] = true
-    Globals.MakeReadWriteGlobal(GapObj("ERROR_OUTPUT"))
-    Globals.ERROR_OUTPUT = Globals._JULIAINTERFACE_ORIGINAL_ERROR_OUTPUT
-    Globals.MakeReadOnlyGlobal(GapObj("ERROR_OUTPUT"))
+    replace_global!(:ERROR_OUTPUT, Globals._JULIAINTERFACE_ORIGINAL_ERROR_OUTPUT)
 
     # enable break loop
     Globals.BreakOnError = true
@@ -40,9 +38,7 @@ function prompt()
 
     # restore GAP.jl error handler
     disable_error_handler[] = false
-    Globals.MakeReadWriteGlobal(GapObj("ERROR_OUTPUT"))
-    Globals.ERROR_OUTPUT = Globals._JULIAINTERFACE_ERROR_OUTPUT
-    Globals.MakeReadOnlyGlobal(GapObj("ERROR_OUTPUT"))
+    replace_global!(:ERROR_OUTPUT, Globals._JULIAINTERFACE_ERROR_OUTPUT)
 end
 
 # helper function for `gap.sh` scripts created by create_gap_sh()

src/wrappers.jl

@@ -53,6 +53,7 @@ import GAP: @wrap
 @wrap LQUO(x::Any, y::Any)::Any
 @wrap LT(x::Any, y::Any)::Bool
 @wrap MakeReadOnlyGlobal(x::Any)::Nothing
+@wrap MakeReadWriteGlobal(x::Any)::Nothing
 @wrap MOD(x::Any, y::Any)::Any
 @wrap NextIterator(x::Any)::Any
 @wrap NormalizedWhitespace(x::GapObj)::GapObj