Annotation tweaks in preparation for Base changes

src/styledmarkup.jl

@@ -5,7 +5,7 @@
 
 module StyledMarkup
 
-using Base: AnnotatedString, annotatedstring
+using Base: AnnotatedString, annotations, annotatedstring
 using ..StyledStrings: Face, SimpleColor
 
 export @styled_str, styled
@@ -97,7 +97,7 @@ function addpart!(state::State, stop::Int)
                     range = (start - state.point[]):(stop - state.point[] + state.offset[] + 1)
                     push!(styles, tupl(range, annot))
                 end
-                sort!(state.pending_styles, by = (r -> (first(r), -last(r))) ∘ first) # see `Base._annot_sortkey`
+                sort!(state.pending_styles, by = (r -> (first(r), -last(r))) ∘ first) # Prioritise the most specific styles
                 for (range, annot) in state.pending_styles
                     if !isempty(range)
                         push!(styles, tupl(range .- state.point[], annot))
@@ -135,11 +135,15 @@ function addpart!(state::State, start::Int, expr, stop::Int)
         else
             push!(state.parts,
                 :(let $str = string($expr)
-                      if isempty($str)
-                          ""
+                      $len = ncodeunits($str) # Used in `annots`.
+                      if $str isa AnnotatedString && !isempty($str)
+                          AnnotatedString(String($str), vcat($annots, annotations($str)))
                       else
-                          $len = ncodeunits($str)
-                          AnnotatedString($str, $annots)
+                          if isempty($str)
+                              ""
+                          else
+                              AnnotatedString($str, $annots)
+                          end
                       end
                   end))
         end
@@ -641,6 +645,36 @@ function run_state_machine!(state::State)
     end
 end
 
+"""
+    annotatedstring_optimize!(str::AnnotatedString)
+
+Merge contiguous identical annotations in `str`.
+"""
+function annotatedstring_optimize!(s::AnnotatedString)
+    last_seen = Dict{Pair{Symbol, Any}, Int}()
+    i = 1
+    while i <= length(s.annotations)
+        region, keyval = s.annotations[i]
+        prev = get(last_seen, keyval, 0)
+        if prev > 0
+            lregion, _ = s.annotations[prev]
+            if last(lregion) + 1 == first(region)
+                s.annotations[prev] =
+                    setindex(s.annotations[prev],
+                             first(lregion):last(region),
+                             1)
+                deleteat!(s.annotations, i)
+            else
+                delete!(last_seen, keyval)
+            end
+        else
+            last_seen[keyval] = i
+            i += 1
+        end
+    end
+    s
+end
+
 """
     @styled_str -> AnnotatedString
 
@@ -740,7 +774,7 @@ macro styled_str(raw_content::String)
     elseif state.interpolated[]
         :(annotatedstring($(state.parts...)))
     else
-        annotatedstring(map(Base.Fix1(hygienic_eval, state), state.parts)...) |> Base.annotatedstring_optimize!
+        annotatedstring(map(Base.Fix1(hygienic_eval, state), state.parts)...) |> annotatedstring_optimize!
     end
 end
 
@@ -762,7 +796,7 @@ function styled(content::AbstractString)
     if !isempty(state.errors)
         throw(MalformedStylingMacro(state.content, state.errors))
     else
-        annotatedstring(state.parts...) |> Base.annotatedstring_optimize!
+        annotatedstring(state.parts...) |> annotatedstring_optimize!
     end
 end