From 9b125f53c880784357cb2e2ce3807ddfdb0b79de Mon Sep 17 00:00:00 2001
From: Juergen Fuhrmann <juergen.fuhrmann@wias-berlin.de>
Date: Fri, 4 Sep 2020 16:14:35 +0200
Subject: [PATCH] Added optional hashify_block_comments filter before parsing.
 Config is on by default.

---
 src/Literate.jl  | 43 ++++++++++++++++++++++++++++++++++++++++++-
 test/runtests.jl |  8 ++++++--
 2 files changed, 48 insertions(+), 3 deletions(-)

diff --git a/src/Literate.jl b/src/Literate.jl
index 4d118d0..ec9de03 100644
--- a/src/Literate.jl
+++ b/src/Literate.jl
@@ -216,6 +216,7 @@ function create_configuration(inputfile; user_config, user_kwargs, type=nothing)
     cfg["documenter"] = true
     cfg["credit"] = true
     cfg["keep_comments"] = false
+    cfg["hashify_block_comments"] = true
     cfg["execute"] = type === :md ? false : true
     cfg["codefence"] = get(user_config, "documenter", true) && !get(user_config, "execute", cfg["execute"]) ?
         ("```@example $(get(user_config, "name", cfg["name"]))" => "```") : ("```julia" => "```")
@@ -298,6 +299,40 @@ See the manual section about [Configuration](@ref) for more information.
 """
 const DEFAULT_CONFIGURATION=nothing # Dummy const for documentation
 
+
+# Turn block comments starting in the first column into "normal" hash comments
+function hashify_block_comments(input)
+    lines_in = collect(eachline(IOBuffer(input)))
+    lines_out=IOBuffer()
+    line_number=0
+    in_block_comment_region=false
+    for line in lines_in
+        line_number+=1
+        if occursin(r"^#=", line)
+            if in_block_comment_region
+                error("line $(line_number): already in block comment region\n$(line)")
+            end
+            println(lines_out,replace(line,r"^#=" => "#"))
+            in_block_comment_region=true
+        elseif occursin(r"^=#", line)
+            if !in_block_comment_region
+                error("line $(line_number): not in block comment region\n$(line)")
+            end
+            println(lines_out,replace(line,r"^=#" => "#"))
+            in_block_comment_region=false
+        else
+            if in_block_comment_region
+                println(lines_out,"# "*line)
+            else
+                println(lines_out,line)
+            end
+        end
+    end
+    return String(take!(lines_out))
+end
+
+
+
 function preprocessor(inputfile, outputdir; user_config, user_kwargs, type)
     # Create configuration by merging default and userdefined
     config = create_configuration(inputfile; user_config=user_config,
@@ -323,9 +358,15 @@ function preprocessor(inputfile, outputdir; user_config, user_kwargs, type)
     # read content
     content = read(inputfile, String)
 
+        
     # run custom pre-processing from user
     content = config["preprocess"](content)
-
+        
+    # hashify block comments
+    if config["hashify_block_comments"]
+        content=hashify_block_comments(content)
+    end
+        
     # run some Documenter specific things for markdown output
     if type === :md && config["documenter"]::Bool
         # change the Edit on GitHub link
diff --git a/test/runtests.jl b/test/runtests.jl
index b054736..25263a6 100644
--- a/test/runtests.jl
+++ b/test/runtests.jl
@@ -108,6 +108,9 @@ end
         ## Line 77
         ##
         ## Line 79
+    #=
+    Line 81
+    =#
     """
     expected_chunks = Chunk[
         MDChunk(["" => "Line 1"]),
@@ -145,8 +148,9 @@ end
         CodeChunk(["Line 64", "    # Line 65", "    Line 66", "Line 67"], false),
         CodeChunk(["# Line 73", "#", "# Line 75"], false),
         CodeChunk(["    # Line 77", "    #", "    # Line 79"], false),
-        ]
-    parsed_chunks = Literate.parse(content)
+        MDChunk(["" => "Line 81"]),
+      ] 
+    parsed_chunks = Literate.parse(Literate.hashify_block_comments(content))
     compare_chunks(parsed_chunks, expected_chunks)
 
     # test leading/trailing whitespace removal