Merge pull request #67 from Omikhleia/feat-mark-extension

feat: Support `mark` (highlight) extension
jgm · Sep 27, 2023 · 55bfb1f · 55bfb1f
2 parents 8e8c309 + 619e8f3
commit 55bfb1f
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Showing 4 changed files with 44 additions and 3 deletions.
diff --git a/bin/lunamark b/bin/lunamark
@@ -281,6 +281,10 @@ environment variable `LUNAMARK_EXTENSIONS` (see ENVIRONMENT below).
 :   Enable strike-through support for a text enclosed within double
     tildes, as in `~~deleted~~`.
 
+`(-) mark`
+:   Enable highlighting support for a text enclosed within double
+    equals, as in `==marked==`.
+
 `(-) subscript`
 :   Enable superscript support. Superscripts may be written by surrounding
     the subscripted text by `~` characters, as in `2~10~`.
@@ -519,6 +523,7 @@ given in parentheses:
   (-) fancy_lists          Pandoc style fancy lists
   (-) task_list            GitHub-Flavored Markdown task list
   (-) strikeout            Strike-through with double tildes
+  (-) mark                 Highlight with double equals
   (-) subscript            Subscripted text between tildes
   (-) superscript          Superscripted text between circumflexes
   (-) bracketed_spans      Spans with attributes
@@ -590,6 +595,7 @@ local extensions = {  -- defaults
   fancy_lists = false,
   task_list = false,
   strikeout = false,
+  mark = false,
   subscript = false,
   superscript = false,
   bracketed_spans = false,

diff --git a/lunamark/reader/markdown.lua b/lunamark/reader/markdown.lua
@@ -102,6 +102,7 @@ parsers.citation_chars         = parsers.alphanumeric
 parsers.internal_punctuation   = S(":;,.?")
 
 parsers.doubleasterisks        = P("**")
+parsers.doubleequals           = P("==")
 parsers.doubleunderscores      = P("__")
 parsers.doubletildes           = P("~~")
 parsers.fourspaces             = P("    ")
@@ -752,6 +753,10 @@ end
 --     :   Enable strike-through support for a text enclosed within double
 --         tildes, as in `~~deleted~~`.
 --
+--     `mark`
+--     :   Enable highlighting support for a text enclosed within double
+--         equals, as in `==marked==`.
+--
 --     `superscript`
 --     :   Enable superscript support. Superscripts may be written by surrounding
 --         the superscripted text by `^` characters, as in `2^10^.
@@ -922,11 +927,14 @@ function M.new(writer, options)
   -- Basic parsers (local)
   ------------------------------------------------------------------------------
 
+  local specials = "*_~`&[]<!\\-@^"
   if options.smart then
-    larsers.specialchar       = S("*_~`&[]<!\\'\"-.@^")
-  else
-    larsers.specialchar       = S("*_~`&[]<!\\-@^")
+    specials = specials .. "'.\""
+  end
+  if options.mark then
+    specials = specials .. "="
   end
+  larsers.specialchar         = S(specials)
 
   larsers.normalchar          = parsers.any - (larsers.specialchar
                                                 + parsers.spacing
@@ -1209,6 +1217,12 @@ function M.new(writer, options)
                                    parsers.doubletildes)
                    ) / writer.strikeout
 
+  larsers.Mark = parsers.between(parsers.Inline, parsers.doubleequals,
+                                 parsers.doubleequals)
+               / function (inlines)
+                   return writer.span(inlines, { class="mark" })
+                 end
+
   larsers.Span   = ( parsers.between(parsers.Inline, parsers.lbracket,
                                    parsers.rbracket) ) * ( parsers.attributes )
                    / writer.span
@@ -1799,6 +1813,7 @@ function M.new(writer, options)
                             + V("Emph")
                             + V("Span")
                             + V("Strikeout")
+                            + V("Mark")
                             + V("Subscript")
                             + V("Superscript")
                             + V("InlineNote")
@@ -1824,6 +1839,7 @@ function M.new(writer, options)
       Emph                  = larsers.Emph,
       Span                  = larsers.Span,
       Strikeout             = larsers.Strikeout,
+      Mark                  = larsers.Mark,
       Subscript             = larsers.Subscript,
       Superscript           = larsers.Superscript,
       InlineNote            = larsers.InlineNote,
@@ -1878,6 +1894,10 @@ function M.new(writer, options)
     syntax.Strikeout = parsers.fail
   end
 
+  if not options.mark then
+    syntax.Mark = parsers.fail
+  end
+
   if not options.raw_attribute then
     syntax.RawInLine = parsers.fail
   end

diff --git a/lunamark/writer/html5.lua b/lunamark/writer/html5.lua
@@ -16,6 +16,8 @@ function M.new(options)
   options = options or {}
   local Html5 = html.new(options)
 
+  local htmlSpan = Html5.span -- inherited, for overriding
+
   Html5.container = "section"
 
   Html5.template = [[
@@ -36,6 +38,14 @@ $body
     return {"<del>", s, "</del>"}
   end
 
+  function Html5.span(s, attr)
+    -- HTML5 has semantic <mark>
+    if attr.class == "mark" then
+      return {"<mark>", s, "</mark>"}
+    end
+    return htmlSpan(s, attr)
+  end
+
   return Html5
 end
 

diff --git a/tests/lunamark/ext_mark.test b/tests/lunamark/ext_mark.test
@@ -0,0 +1,5 @@
+lunamark -Xmark
+<<<
+Some ==highlighted text==.
+>>>
+<p>Some <span class="mark">highlighted text</span>.</p>