From f62d953da8069c3f8d67046a8e2879f2272ff882 Mon Sep 17 00:00:00 2001
From: Fredrik Ekre <ekrefredrik@gmail.com>
Date: Sat, 12 Sep 2020 16:19:00 +0200
Subject: [PATCH] Support multiline comments for markdown input, fixes #26.

---
 docs/src/fileformat.md | 25 +++++++++++++++++++++++++
 src/Literate.jl        |  9 +++++++++
 test/runtests.jl       | 23 +++++++++++++++++++++++
 3 files changed, 57 insertions(+)

diff --git a/docs/src/fileformat.md b/docs/src/fileformat.md
index 2892c85..d9eefa4 100644
--- a/docs/src/fileformat.md
+++ b/docs/src/fileformat.md
@@ -45,6 +45,31 @@ For simple use this is all you need to know. The following additional special sy
 There is also some default convenience replacements that will always be performed, see
 [Default Replacements](@ref).
 
+!!! compat "Multiline comments in Literate 2.7"
+    Literate version 2.7 adds support for Julia multiline comments for markdown input.
+    All multiline comments in the input are rewritten to regular comments as part of the
+    preprocessing step, before any other processing is performed. For Literate to recognize
+    multiline comments it is required that the start token (`#=`) and end token (`=#`) are
+    placed on their own lines. Note also that it is allowed to have more than one `=` in the
+    tokens, for example
+    ```juila
+    #=
+    This multiline comment
+    is treated as markdown.
+    =#
+
+    #=====================
+    This is also markdown.
+    =====================#
+    ```
+    is rewritten to
+    ```juila
+    # This multiline comment
+    # is treated as markdown.
+
+    # This is also markdown.
+    ```
+
 
 ## [**2.2.** Filtering Lines](@id Filtering-Lines)
 
diff --git a/src/Literate.jl b/src/Literate.jl
index 4d118d0..92cf041 100644
--- a/src/Literate.jl
+++ b/src/Literate.jl
@@ -146,6 +146,15 @@ function replace_default(content, sym;
 
     push!(repls, "\r\n" => "\n") # normalize line endings
 
+    # unconditionally rewrite multiline comments to regular comments
+    multiline_r = r"^#=+$\R^(\X*?)\R^=+#$"m
+    while (m = match(multiline_r, content); m !== nothing)
+        newlines = sprint() do io
+            foreach(l -> println(io, "# ", l), eachline(IOBuffer(m[1])))
+        end
+        content = replace(content, multiline_r => chop(newlines); count=1)
+    end
+
     # unconditionally remove #src lines
     push!(repls, r"^#src.*\n?"m => "") # remove leading #src lines
     push!(repls, r".*#src$\n?"m => "") # remove trailing #src lines
diff --git a/test/runtests.jl b/test/runtests.jl
index b054736..2a7b135 100644
--- a/test/runtests.jl
+++ b/test/runtests.jl
@@ -255,6 +255,15 @@ content = """
     #nb #-
     #nb # %% [markdown] {"meta": "data"}
     #nb # # Explicit markdown cell with metadata
+
+    #=
+    First multiline
+    comment
+    =#
+
+    #=======================
+    Second multiline comment
+    =======================#
     """
 
 const TRAVIS_ENV = Dict(
@@ -424,6 +433,8 @@ const GITLAB_ENV = Dict(
             @test occursin("# # Example", script)
             @test occursin("# foo, bar", script)
             @test occursin("# \\int f(x) dx", script)
+            @test occursin("# First multiline", script)
+            @test occursin("# Second multiline comment", script)
 
             # verify that inputfile exists
             @test_throws ArgumentError Literate.script("nonexistent.jl", outdir)
@@ -556,6 +567,11 @@ end end
             hidden2 * hidden2
             ```
 
+            First multiline
+            comment
+
+            Second multiline comment
+
             ---
 
             *This page was generated using [Literate.jl](https://github.com/fredrikekre/Literate.jl).*
@@ -877,6 +893,13 @@ end end
                }
             """,
 
+            """
+               "source": [
+                "First multiline\\n",
+                "comment"
+               ]
+            """,
+
             """
                "source": [
                 "---\\n",