Add ::MIME"text/plain" versions of show_special macros (Nemocas#1583)

Author: joschmitt

src/AbstractAlgebra.jl

@@ -462,6 +462,19 @@ macro show_special(io, O)
   end )
 end
 
+macro show_special(io, mime, O)
+  return :( begin
+    local i = $(esc(io))
+    local m = $(esc(mime))
+    local o = $(esc(O))
+    s = get_attribute(o, :show)
+    if s !== nothing
+      s(i, m, o)
+      return
+    end
+  end )
+end
+
 macro show_special_elem(io, e)
   return :( begin
     local i = $(esc(io))
@@ -475,6 +488,20 @@ macro show_special_elem(io, e)
   end )
 end
 
+macro show_special_elem(io, mime, e)
+  return :( begin
+    local i = $(esc(io))
+    local m = $(esc(mime))
+    local a = $(esc(e))
+    local o = parent(a)
+    s = get_attribute(o, :show_elem)
+    if s !== nothing
+      s(i, m, a)
+      return
+    end
+  end )
+end
+
 ###############################################################################
 # generic fall back if no immediate coercion is possible
 # can/ should be called for more generic general coercion mechanisms