Implement mime chooser for markdown output

src/Literate.jl

@@ -6,7 +6,7 @@ https://fredrikekre.github.io/Literate.jl/ for documentation.
 """
 module Literate
 
-import JSON, REPL, IOCapture
+import JSON, REPL, IOCapture, Base64
 
 include("IJulia.jl")
 import .IJulia
@@ -648,10 +648,8 @@ function execute_markdown!(io::IO, sb::Module, block::String, outputdir;
     plain_fence = "\n````\n" =>  "\n````"
 
     # Any explicit calls to display(...)
-    for dict in display_dicts
-        for (mime, data) in dict
-            display_markdown(io, data, outputdir, flavor, image_formats, file_prefix, plain_fence)
-        end
+    for (i, d) in enumerate(display_dicts)
+        display_markdown_mime(io, d, outputdir, flavor, image_formats, "$(file_prefix)-$i", plain_fence)
     end
 
     if r !== nothing && !REPL.ends_with_semicolon(block)
@@ -678,7 +676,7 @@ function display_markdown(io, data, outputdir, flavor, image_formats, file_prefi
             open(joinpath(outputdir, file), "w") do io
                 Base.invokelatest(show, io, mime, data)
             end
-            write(io, "![](", file, ")\n")
+            write(io, "\n![](", file, ")\n")
             return
         end
     end
@@ -695,6 +693,52 @@ function display_markdown(io, data, outputdir, flavor, image_formats, file_prefi
     return
 end
 
+function display_markdown_mime(io, mime_dict, outputdir, flavor, image_formats, file_prefix, plain_fence)
+    if (flavor isa FranklinFlavor || flavor isa DocumenterFlavor) &&
+        haskey(mime_dict, "text/html")
+        htmlfence = flavor isa FranklinFlavor ? ("~~~" => "~~~") : ("```@raw html" => "```")
+        data = mime_dict["text/html"]
+        write(io, "\n", htmlfence.first, "\n")
+        write(io, data)
+        write(io, "\n", htmlfence.second, "\n")
+        return
+    end
+
+    for (mime, ext) in image_formats
+        if haskey(mime_dict, string(mime))
+            data = mime_dict[string(mime)]
+            file = file_prefix * ext
+            if istextmime(mime)
+                write(joinpath(outputdir, file), data)
+            else
+                data_decoded = Base64.base64decode(data)
+                write(joinpath(outputdir, file), data_decoded)
+            end
+            write(io, "\n![](", file, ")\n")
+            return
+        end
+    end
+
+    if haskey(mime_dict, "text/latex")
+        data = mime_dict["text/latex"]
+        write(io, "\n```latex\n", data, "\n```\n")
+        return
+    end
+
+    if haskey(mime_dict, "text/markdown")
+        data = mime_dict["text/markdown"]
+        write(io, '\n', data, '\n')
+        return
+    end
+
+    # fallback to text/plain
+    @assert haskey(mime_dict, "text/plain")
+    write(io, plain_fence.first)
+    write(io, mime_dict["text/plain"])
+    write(io, plain_fence.second, '\n')
+end
+
+
 const JUPYTER_VERSION = v"4.3.0"
 
 parse_nbmeta(line::Pair) = parse_nbmeta(line.second)

test/runtests.jl

@@ -987,25 +987,52 @@ end end
 
             # Calls to display(x) and display(mime, x)
             script = """
-            struct DF x end
-            Base.show(io::IO, ::MIME"text/plain", df::DF) = print(io, "DF(\$(df.x)) as text/plain")
-            Base.show(io::IO, ::MIME"text/html", df::DF) = print(io, "DF(\$(df.x)) as text/html")
-            Base.show(io::IO, ::MIME"text/latex", df::DF) = print(io, "DF(\$(df.x)) as text/latex")
+            struct DF{N} x end
+            DF(x) = DF{x}(x)
+            Base.show(io::IO, ::MIME"text/plain", df::DF{1}) = print(io, "DF(\$(df.x)) as text/plain")
+            Base.show(io::IO, ::MIME"text/html", df::DF{2}) = print(io, "DF(\$(df.x)) as text/html")
+            Base.show(io::IO, ::MIME"text/markdown", df::DF{3}) = print(io, "DF(\$(df.x)) as text/markdown")
+            Base.show(io::IO, ::MIME"text/latex", df::DF{4}) = print(io, "DF(\$(df.x)) as text/latex")
+            Base.show(io::IO, ::MIME"image/svg+xml", df::DF{5}) = print(io, "DF(\$(df.x)) as image/svg+xml")
+            Base.show(io::IO, ::MIME"image/png", df::DF{6}) = print(io, "DF(\$(df.x)) as image/png")
             #-
-            foreach(display, [DF(1), DF(2)])
-            DF(3)
+            foreach(display, [DF(1), DF(2), DF(3), DF(4), DF(5)])
+            DF(6)
             #-
             display(MIME("text/latex"), DF(4))
             """
             write(inputfile, script)
             Literate.markdown(inputfile, outdir; execute=true)
             markdown = read(joinpath(outdir, "inputfile.md"), String)
-            @test occursin("````\n\"DF(1) as text/plain\"\n````", markdown)
-            @test occursin("````\n\"DF(1) as text/html\"\n````", markdown)
-            @test occursin("````\n\"DF(2) as text/plain\"\n````", markdown)
-            @test occursin("````\n\"DF(2) as text/html\"\n````", markdown)
-            @test occursin("```@raw html\nDF(3) as text/html\n```", markdown)
-            @test occursin("````\n\"DF(4) as text/latex\"\n````", markdown)
+
+            # Make sure each one shows up.
+            @test occursin("DF(1)", markdown)
+            @test occursin("DF(2)", markdown)
+            @test occursin("DF(3)", markdown)
+            @test occursin("DF(4)", markdown)
+            @test occursin("inputfile-3-5.svg", markdown)
+            @test occursin("inputfile-3.png", markdown)
+
+            # Check the ordering.
+            @test findfirst("DF(1)", markdown)[1] < findfirst("DF(2)", markdown)[1]
+            @test findfirst("DF(2)", markdown)[1] < findfirst("DF(3)", markdown)[1]
+            @test findfirst("DF(3)", markdown)[1] < findfirst("DF(4)", markdown)[1]
+            @test findfirst("DF(4)", markdown)[1] < findfirst("inputfile-3-5.svg", markdown)[1]
+            @test findfirst("inputfile-3-5.svg", markdown)[1] < findfirst("inputfile-3.png", markdown)[1]
+
+            # Check the formatting.
+            @test occursin("````\nDF(1) as text/plain\n````", markdown)
+            @test occursin("```@raw html\nDF(2) as text/html\n```", markdown)
+            @test occursin("\nDF(3) as text/markdown\n", markdown)
+            @test occursin("```latex\nDF(4) as text/latex\n```", markdown)
+            @test occursin("\n![](inputfile-3-5.svg)\n", markdown)
+            @test occursin("\n![](inputfile-3.png)\n", markdown)
+
+            svg = read(joinpath(outdir, "inputfile-3-5.svg"), String)
+            @test svg == "DF(5) as image/svg+xml"
+
+            png = read(joinpath(outdir, "inputfile-3.png"), String)
+            @test png == "DF(6) as image/png"
 
             # Softscope
             write(