add support for groff mom filter

4 files changed, 290 insertions, 2 deletions

diff --git a/src/CMakeLists.txt b/src/CMakeLists.txt
index 48ddd01..d4e2a57 100644
--- a/src/CMakeLists.txt
+++ b/src/CMakeLists.txt
@@ -40,6 +40,7 @@ set(LIBRARY_SOURCES
   houdini_html_e.c
   houdini_html_u.c
   cmark_ctype.c
+  mom.c
   ${HEADERS}
   )
 
diff --git a/src/cmark.h b/src/cmark.h
index a37c185..afd90e9 100644
--- a/src/cmark.h
+++ b/src/cmark.h
@@ -536,6 +536,12 @@ char *cmark_render_commonmark(cmark_node *root, int options, int width);
 CMARK_EXPORT
 char *cmark_render_latex(cmark_node *root, int options, int width);
 
+/** Render a 'node' tree as a groff mom document.
+ * It is the caller's responsibility to free the returned buffer.
+ */
+CMARK_EXPORT
+char *cmark_render_mom(cmark_node *root, int options, int width);
+
 /**
  * ## Options
  */
diff --git a/src/main.c b/src/main.c
index 0cc2b3d..17bfcfa 100644
--- a/src/main.c
+++ b/src/main.c
@@ -25,14 +25,15 @@ typedef enum {
   FORMAT_XML,
   FORMAT_MAN,
   FORMAT_COMMONMARK,
-  FORMAT_LATEX
+  FORMAT_LATEX,
+  FORMAT_MOM
 } writer_format;
 
 void print_usage() {
   printf("Usage:   cmark [FILE*]\n");
   printf("Options:\n");
   printf("  --to, -t FORMAT  Specify output format (html, xml, man, "
-         "commonmark, latex)\n");
+         "commonmark, latex, mom)\n");
   printf("  --width WIDTH    Specify wrap width (default 0 = nowrap)\n");
   printf("  --sourcepos      Include source position attribute\n");
   printf("  --hardbreaks     Treat newlines as hard line breaks\n");
@@ -65,6 +66,9 @@ static void print_document(cmark_node *document, writer_format writer,
   case FORMAT_LATEX:
     result = cmark_render_latex(document, options, width);
     break;
+  case FORMAT_MOM:
+    result = cmark_render_mom(document, options, width);
+    break;
   default:
     fprintf(stderr, "Unknown format %d\n", writer);
     exit(1);
@@ -148,6 +152,8 @@ int main(int argc, char *argv[]) {
           writer = FORMAT_COMMONMARK;
         } else if (strcmp(argv[i], "latex") == 0) {
           writer = FORMAT_LATEX;
+        } else if (strcmp(argv[i], "mom") == 0) {
+          writer = FORMAT_MOM;
         } else {
           fprintf(stderr, "Unknown format %s\n", argv[i]);
           exit(1);
diff --git a/src/mom.c b/src/mom.c
new file mode 100644
index 0000000..aa866f0
--- /dev/null
+++ b/src/mom.c
@@ -0,0 +1,275 @@
+#include <stdlib.h>
+#include <stdio.h>
+#include <string.h>
+#include <assert.h>
+
+#include "config.h"
+#include "cmark.h"
+#include "node.h"
+#include "buffer.h"
+#include "utf8.h"
+#include "render.h"
+
+#define OUT(s, wrap, escaping) renderer->out(renderer, s, wrap, escaping)
+#define LIT(s) renderer->out(renderer, s, false, LITERAL)
+#define CR() renderer->cr(renderer)
+#define BLANKLINE() renderer->blankline(renderer)
+#define LIST_NUMBER_SIZE 20
+
+// Functions to convert cmark_nodes to groff man strings.
+static void S_outc(cmark_renderer *renderer, cmark_escaping escape, int32_t c,
+                   unsigned char nextc) {
+  (void)(nextc);
+
+  if (escape == LITERAL) {
+    cmark_render_code_point(renderer, c);
+    return;
+  }
+
+  switch (c) {
+  case 46:
+    if (renderer->begin_line) {
+      cmark_render_ascii(renderer, "\\&.");
+    } else {
+      cmark_render_code_point(renderer, c);
+    }
+    break;
+  case 39:
+    if (renderer->begin_line) {
+      cmark_render_ascii(renderer, "\\&'");
+    } else {
+      cmark_render_code_point(renderer, c);
+    }
+    break;
+  case 45:
+    cmark_render_ascii(renderer, "\\-");
+    break;
+  case 92:
+    cmark_render_ascii(renderer, "\\e");
+    break;
+  case 8216: // left single quote
+    cmark_render_ascii(renderer, "\\[oq]");
+    break;
+  case 8217: // right single quote
+    cmark_render_ascii(renderer, "\\[cq]");
+    break;
+  case 8220: // left double quote
+    cmark_render_ascii(renderer, "\\[lq]");
+    break;
+  case 8221: // right double quote
+    cmark_render_ascii(renderer, "\\[rq]");
+    break;
+  case 8212: // em dash
+    cmark_render_ascii(renderer, "\\[em]");
+    break;
+  case 8211: // en dash
+    cmark_render_ascii(renderer, "\\[en]");
+    break;
+  default:
+    cmark_render_code_point(renderer, c);
+  }
+}
+
+static int S_render_node(cmark_renderer *renderer, cmark_node *node,
+                         cmark_event_type ev_type, int options) {
+  bool entering = (ev_type == CMARK_EVENT_ENTER);
+  bool allow_wrap = renderer->width > 0 && !(CMARK_OPT_NOBREAKS & options);
+  char s_tmp[128];
+
+
+  // avoid unused parameter error:
+  (void)(options);
+
+  switch (node->type) {
+  case CMARK_NODE_DOCUMENT:
+    if (entering) {
+      LIT(".DOCTYPE DEFAULT");
+      CR();
+      LIT(".PRINTSTYLE TYPESET");
+      CR();
+      LIT(".JUSTIFY");
+      CR();
+      LIT(".START");
+      CR();
+      CR();
+    }
+    break;
+
+  case CMARK_NODE_BLOCK_QUOTE:
+    if (entering) {
+      CR();
+      LIT(".BLOCKQUOTE");
+      CR();
+    } else {
+      CR();
+      LIT(".BLOCKQUOTE END");
+      CR();
+    }
+    break;
+
+  case CMARK_NODE_LIST:
+    if (entering) {
+      CR();
+      LIT(".LIST ");
+      CR();
+      LIT(".SHIFT_LIST 20p");
+      if (cmark_node_get_list_type(node) == CMARK_BULLET_LIST) {
+        LIT("BULLET");
+      } else {
+        LIT("DIGIT");
+      }
+      CR();
+    } else {
+      CR();
+      LIT(".LIST OFF");
+      CR();
+    }
+    break;
+
+  case CMARK_NODE_ITEM:
+    if (entering) {
+      CR();
+      LIT(".ITEM");
+      CR();
+    } else {
+      CR();
+    }
+    break;
+
+  case CMARK_NODE_HEADING:
+    if (entering) {
+      CR();
+      sprintf(s_tmp, ".HEADING %d \"", cmark_node_get_heading_level(node));
+      LIT(s_tmp);
+    } else {
+      LIT("\"");
+      CR();
+    }
+    break;
+
+
+  case CMARK_NODE_CODE_BLOCK:
+    CR();
+    LIT(".QUOTE");
+    CR();
+    LIT(".CODE BR");
+    CR();
+    OUT(cmark_node_get_literal(node), false, NORMAL);
+    CR();
+    LIT(".QUOTE OFF");
+    CR();
+    break;
+
+  case CMARK_NODE_HTML_BLOCK:
+    break;
+
+  case CMARK_NODE_CUSTOM_BLOCK:
+    CR();
+    OUT(entering ? cmark_node_get_on_enter(node) : cmark_node_get_on_exit(node),
+        false, LITERAL);
+    CR();
+    break;
+
+  case CMARK_NODE_THEMATIC_BREAK:
+    CR();
+    LIT(".PP\n  *  *  *  *  *");
+    CR();
+    break;
+
+  case CMARK_NODE_PARAGRAPH:
+    if (entering) {
+      // no blank line if first paragraph in list:
+        CR();
+        LIT(".PP");
+        CR();
+    } else {
+      CR();
+    }
+    break;
+
+  case CMARK_NODE_TEXT:
+    OUT(cmark_node_get_literal(node), allow_wrap, NORMAL);
+    break;
+
+  case CMARK_NODE_LINEBREAK:
+    CR();
+    LIT(".BR");
+    CR();
+    break;
+
+  case CMARK_NODE_SOFTBREAK:
+    if (options & CMARK_OPT_HARDBREAKS) {
+      LIT(".PD 0\n.P\n.PD");
+      CR();
+    } else if (renderer->width == 0 && !(CMARK_OPT_NOBREAKS & options)) {
+      CR();
+    } else {
+      OUT(" ", allow_wrap, LITERAL);
+    }
+    break;
+
+  case CMARK_NODE_CODE:
+    LIT("\\f[C]");
+    OUT(cmark_node_get_literal(node), allow_wrap, NORMAL);
+    LIT("\\f[]");
+    break;
+
+  case CMARK_NODE_HTML_INLINE:
+    break;
+
+  case CMARK_NODE_CUSTOM_INLINE:
+    OUT(entering ? cmark_node_get_on_enter(node) : cmark_node_get_on_exit(node),
+        false, LITERAL);
+    break;
+
+  case CMARK_NODE_STRONG:
+    if (entering) {
+      CR();
+      LIT(".SETBOLDER");
+      CR();
+    } else {
+      CR();
+      LIT(".SETBOLDER RESET");
+      CR();
+    }
+    break;
+
+  case CMARK_NODE_EMPH:
+    if (entering) {
+      CR();
+      LIT(".SETSLANT");
+      CR();
+    } else {
+      CR();
+      LIT(".SETSLANT RESET");
+      CR();
+    }
+    break;
+
+  case CMARK_NODE_LINK:
+    if (!entering) {
+      LIT(" (");
+      OUT(cmark_node_get_url(node), allow_wrap, URL);
+      LIT(")");
+    }
+    break;
+
+  case CMARK_NODE_IMAGE:
+    if (entering) {
+      LIT("[IMAGE: ");
+    } else {
+      LIT("]");
+    }
+    break;
+
+  default:
+    assert(false);
+    break;
+  }
+
+  return 1;
+}
+
+char *cmark_render_mom(cmark_node *root, int options, int width) {
+  return cmark_render(root, options, width, S_outc, S_render_node);
+}