From cc15dfacd6ee5a28d8a058ce5439645071836c0b Mon Sep 17 00:00:00 2001
From: Sebastian Gutsche <gutsche@mathematik.uni-siegen.de>
Date: Mon, 17 Jun 2019 17:19:23 +0200
Subject: [PATCH] Enable ? help for `GAP.Globals.FOO`

---
 pkg/GAPJulia/JuliaInterface/julia/libgap.jl | 19 ++++++++++++++++
 src/GAP.jl                                  |  1 +
 src/gap2.jl                                 |  5 -----
 src/help.jl                                 | 25 +++++++++++++++++++++
 4 files changed, 45 insertions(+), 5 deletions(-)
 create mode 100644 pkg/GAPJulia/JuliaInterface/julia/libgap.jl
 create mode 100644 src/help.jl

diff --git a/pkg/GAPJulia/JuliaInterface/julia/libgap.jl b/pkg/GAPJulia/JuliaInterface/julia/libgap.jl
new file mode 100644
index 00000000..436316d9
--- /dev/null
+++ b/pkg/GAPJulia/JuliaInterface/julia/libgap.jl
@@ -0,0 +1,19 @@
+#
+# This is a very hacky prototype calling libgap from julia
+#
+# It is intended to be a low level interface to the C functions
+# the higher level API can be found in gap.jl
+#
+
+using Libdl
+
+import Base: length, convert
+
+const MPtr = Main.ForeignGAP.MPtr
+
+
+include( "ccalls.jl" )
+include( "gap.jl" )
+include( "gap_to_julia.jl" )
+include( "julia_to_gap.jl" )
+include( "help.jl" )
diff --git a/src/GAP.jl b/src/GAP.jl
index beb668fa..55a99421 100644
--- a/src/GAP.jl
+++ b/src/GAP.jl
@@ -129,5 +129,6 @@ include( "gap2.jl" )
 include( "macros.jl" )
 include( "gap_to_julia.jl" )
 include( "julia_to_gap.jl" )
+include( "help.jl" )
 
 end
diff --git a/src/gap2.jl b/src/gap2.jl
index b13dd61c..e6caf9bc 100644
--- a/src/gap2.jl
+++ b/src/gap2.jl
@@ -144,8 +144,3 @@ function Display(x::GapObj)
         error("variable was not correctly evaluated")
     end
 end
-
-function show_GAP_help( topic::String, onlyexact::Bool=false )
-    print( GAP.gap_to_julia( GAP.Globals.HelpString(
-           GAP.julia_to_gap( topic ), onlyexact ) ) )
-end
diff --git a/src/help.jl b/src/help.jl
new file mode 100644
index 00000000..6d109c06
--- /dev/null
+++ b/src/help.jl
@@ -0,0 +1,25 @@
+function GAP_help_string(topic::String, onlyexact::Bool = false)
+    return GAP.gap_to_julia(GAP.Globals.HelpString(GAP.julia_to_gap(topic), onlyexact))
+end
+
+function show_GAP_help(topic::String, onlyexact::Bool = false)
+    print(GAP_help_string(topic, onlyexact))
+end
+
+import Base.Docs: Binding, getdoc, docstr
+
+## Create a helper type that gets returned by Binding
+struct GAPHelpType
+    name::Symbol
+end
+
+Base.Docs.Binding(x::GlobalsType, name::Symbol) = GAPHelpType(name)
+
+function Base.Docs.doc(x::GAPHelpType, typesig::Type = Union{})
+    return Text(GAP_help_string(string(x.name)))
+end
+
+## Set getdoc for GlobalsType to nothing,
+## so it dispatches on the Binding.
+Base.Docs.getdoc(x::GlobalsType) = nothing
+Base.Docs.getdoc(x::GapObj) = Text(GAP_help_string(gap_to_julia(Globals.NameFunction(x))))