Convert --with-fenced-code to runtime flag for issue Orc#124.

This change is more invasive and difficult for me as not all existing
preprocessor directives directly translate to `if () {}`.

Instead of passing `--with-fenced-code` to `configure.sh`, now use
`MKD_FENCEDCODE` or `-ffencedcode`.

The output of `markdown -VV` will now display `FENCEDCODE` if the
feature is enabled and `!FENCEDCODE` if it is disabled rather than
displaying `FENCED-CODE` if the feature is enabled.

configure.sh

@@ -11,7 +11,6 @@ ac_help='--enable-amalloc	Enable memory allocation debugging
 --with-tabstops=N	Set tabstops to N characters (default is 4)
 --with-id-anchor	Use id= anchors for table-of-contents links
 --with-github-tags	Allow `_` and `-` in <> tags
---with-fenced-code	Allow fenced code blocks
 --with-urlencoded-anchor	Use url-encoded chars to multibyte chars in toc links
 --enable-all-features	Turn on all stable optional features
 --shared		Build shared libraries (default is static)'
@@ -47,14 +46,13 @@ TARGET=markdown
 
 AC_INIT $TARGET
 
-for banned_with in dl; do
-    banned_with_variable_ref=\$WITH_`echo "$banned_with" | $AC_UPPERCASE`
+for banned_with in dl fenced-code; do
+    banned_with_variable_ref=\$WITH_`echo "$banned_with" | $AC_UPPERCASE | tr - _`
     if [ "`eval echo "$banned_with_variable_ref"`" ]; then
 	AC_FAIL "Invalid option: --with-$banned_with. Please use a runtime flag to configure this feature."
     fi
 done
 
-test "$WITH_FENCED_CODE" && AC_DEFINE "WITH_FENCED_CODE" 1
 test "$WITH_ID_ANCHOR" && AC_DEFINE 'WITH_ID_ANCHOR' 1
 test "$WITH_GITHUB_TAGS" && AC_DEFINE 'WITH_GITHUB_TAGS' 1
 test "$WITH_URLENCODED_ANCHOR" && AC_DEFINE 'WITH_URLENCODED_ANCHOR' 1

flags.c

@@ -32,6 +32,7 @@ static struct flagnames flagnames[] = {
     { MKD_NOSTYLE,        "!STYLE" },
     { MKD_NODLDISCOUNT,   "!DLDISCOUNT" },
     { MKD_DLEXTRA,        "DLEXTRA" },
+    { MKD_FENCEDCODE,     "FENCEDCODE" },
 };
 #define NR(x)	(sizeof x/sizeof x[0])
 

markdown.1

@@ -119,6 +119,8 @@ Enable extra-style definition lists (not default). Both styles may be enabled si
 Allow markdown extra-style footnotes.
 .It Ar style
 Extract <style> blocks from the output.
+.It Ar fencedcode
+Allow fenced code blocks (not default).
 .El
 .Pp
 As an example, the option

markdown.3

@@ -112,6 +112,8 @@ Enable the extra definition list syntax style.
 Enable markdown extra-style footnotes.
 .It Ar MKD_NOSTYLE
 Do not extract (omit) <style/> blocks from the output.
+.It Ar MKD_FENCEDCODE
+Allow fenced code blocks.
 .El
 .Sh RETURN VALUES
 .Fn markdown

markdown.c

@@ -178,20 +178,16 @@ splitline(Line *t, int cutpoint)
 
 #define UNCHECK(l) ((l)->flags &= ~CHECKED)
 
-#ifdef WITH_FENCED_CODE
-# define UNLESS_FENCED(t) if (fenced) { \
+#define UNLESS_FENCED(t) if (fenced) { \
     other = 1; l->count += (c == ' ' ? 0 : -1); \
   } else { t; }
-#else
-# define UNLESS_FENCED(t) t;
-#endif
 
 /*
  * walk a line, seeing if it's any of half a dozen interesting regular
  * types.
  */
 static void
-checkline(Line *l)
+checkline(Line *l, DWORD flags)
 {
     int eol, i;
     int dashes = 0, spaces = 0,
@@ -210,6 +206,7 @@ checkline(Line *l)
 
     for (i=l->dle; i<eol; i++) {
 	register int c = T(l->text)[i];
+	int is_fence_char = 0;
 
 	if ( c != ' ' ) l->count++;
 
@@ -219,14 +216,20 @@ checkline(Line *l)
 	case '=':  equals = 1; break;
 	case '_':  UNLESS_FENCED(underscores = 1); break;
 	case '*':  stars = 1; break;
-#if WITH_FENCED_CODE
-	case '~':  if (other) return; fenced = 1; tildes = 1; break;
-	case '`':  if (other) return; fenced = 1; backticks = 1; break;
-#endif
 	default:
-    other = 1;
-    l->count--;
-    if (!fenced) return;
+	    if (flags & MKD_FENCEDCODE) {
+		switch (c) {
+		case '~':  if (other) return; is_fence_char = 1; tildes = 1; break;
+		case '`':  if (other) return; is_fence_char = 1; backticks = 1; break;
+		}
+		if (is_fence_char) {
+		    fenced = 1;
+		    break;
+		}
+	    }
+	    other = 1;
+	    l->count--;
+	    if (!fenced) return;
 	}
     }
 
@@ -242,10 +245,8 @@ checkline(Line *l)
     if ( stars || underscores ) { l->kind = chk_hr; }
     else if ( dashes ) { l->kind = chk_dash; }
     else if ( equals ) { l->kind = chk_equal; }
-#if WITH_FENCED_CODE
     else if ( tildes ) { l->kind = chk_tilde; }
     else if ( backticks ) { l->kind = chk_backtick; }
-#endif
 }
 
 
@@ -372,10 +373,10 @@ iscode(Line *t)
 
 
 static inline int
-ishr(Line *t)
+ishr(Line *t, DWORD flags)
 {
     if ( ! (t->flags & CHECKED) )
-	checkline(t);
+	checkline(t, flags);
 
     if ( t->count > 2 )
 	return t->kind == chk_hr || t->kind == chk_dash || t->kind == chk_equal;
@@ -384,7 +385,7 @@ ishr(Line *t)
 
 
 static int
-issetext(Line *t, int *htyp)
+issetext(Line *t, int *htyp, DWORD flags)
 {
     Line *n;
 
@@ -394,7 +395,7 @@ issetext(Line *t, int *htyp)
 
     if ( (n = t->next) ) {
 	if ( !(n->flags & CHECKED) )
-	    checkline(n);
+	    checkline(n, flags);
 
 	if ( n->kind == chk_dash || n->kind == chk_equal ) {
 	    *htyp = SETEXT;
@@ -406,7 +407,7 @@ issetext(Line *t, int *htyp)
 
 
 static int
-ishdr(Line *t, int *htyp)
+ishdr(Line *t, int *htyp, DWORD flags)
 {
     /* ANY leading `#`'s make this into an ETX header
      */
@@ -417,19 +418,19 @@ ishdr(Line *t, int *htyp)
 
     /* And if not, maybe it's a SETEXT header instead
      */
-    return issetext(t, htyp);
+    return issetext(t, htyp, flags);
 }
 
 
 static inline int
-end_of_block(Line *t)
+end_of_block(Line *t, DWORD flags)
 {
     int dummy;
 
     if ( !t )
 	return 0;
 
-    return ( (S(t->text) <= t->dle) || ishr(t) || ishdr(t, &dummy) );
+    return ( (S(t->text) <= t->dle) || ishr(t, flags) || ishdr(t, &dummy, flags) );
 }
 
 
@@ -471,7 +472,7 @@ is_extra_dt(Line *t, int *clip, DWORD flags)
 		      && T(t->text)[S(t->text)-1] != '=') {
 	Line *x;
 
-	if ( iscode(t) || end_of_block(t) )
+	if ( iscode(t) || end_of_block(t, flags) )
 	    return 0;
 
 	if ( (x = skipempty(t->next)) && is_extra_dd(x) ) {
@@ -506,7 +507,7 @@ islist(Line *t, int *clip, DWORD flags, int *list_type)
     int i, j;
     char *q;
 
-    if ( end_of_block(t) )
+    if ( end_of_block(t, flags) )
 	return 0;
 
     if ( !(flags & (MKD_NODLIST|MKD_STRICT)) && isdefinition(t,clip,list_type,flags) )
@@ -614,12 +615,14 @@ codeblock(Paragraph *p)
 }
 
 
-#ifdef WITH_FENCED_CODE
 static int
-iscodefence(Line *r, int size, line_type kind)
+iscodefence(Line *r, int size, line_type kind, DWORD flags)
 {
+    if ( !(flags & MKD_FENCEDCODE) )
+	return 0;
+
     if ( !(r->flags & CHECKED) )
-	checkline(r);
+	checkline(r, flags);
 
     if ( kind )
 	return (r->kind == kind) && (r->count >= size);
@@ -628,7 +631,7 @@ iscodefence(Line *r, int size, line_type kind)
 }
 
 static Paragraph *
-fencedcodeblock(ParagraphRoot *d, Line **ptr)
+fencedcodeblock(ParagraphRoot *d, Line **ptr, DWORD flags)
 {
     Line *first, *r;
     Paragraph *ret;
@@ -637,14 +640,14 @@ fencedcodeblock(ParagraphRoot *d, Line **ptr)
 
     /* don't allow zero-length code fences
      */
-    if ( (first->next == 0) || iscodefence(first->next, first->count, 0) )
+    if ( (first->next == 0) || iscodefence(first->next, first->count, 0, flags) )
 	return 0;
 
     /* find the closing fence, discard the fences,
      * return a Paragraph with the contents
      */
     for ( r = first; r && r->next; r = r->next )
-	if ( iscodefence(r->next, first->count, first->kind) ) {
+	if ( iscodefence(r->next, first->count, first->kind, flags) ) {
 	    (*ptr) = r->next->next;
 	    ret = Pp(d, first->next, CODE);
       if (S(first->text) - first->count > 0) {
@@ -662,7 +665,6 @@ fencedcodeblock(ParagraphRoot *d, Line **ptr)
 	}
     return 0;
 }
-#endif
 
 
 static int
@@ -688,7 +690,7 @@ endoftextblock(Line *t, int toplevelblock, DWORD flags)
 {
     int z;
 
-    if ( end_of_block(t) || isquote(t) )
+    if ( end_of_block(t, flags) || isquote(t) )
 	return 1;
 
     /* HORRIBLE STANDARDS KLUDGES:
@@ -877,9 +879,9 @@ listitem(Paragraph *p, int indent, DWORD flags, linefn check)
 	    indent = clip ? clip : 2;
 	}
 
-	if ( (q->dle < indent) && (ishr(q) || islist(q,&z,flags,&z)
+	if ( (q->dle < indent) && (ishr(q,flags) || islist(q,&z,flags,&z)
 					   || (check && (*check)(q)))
-			       && !issetext(q,&z) ) {
+			       && !issetext(q,&z,flags) ) {
 	    q = t->next;
 	    t->next = 0;
 	    return q;
@@ -1253,11 +1255,9 @@ compile(Line *ptr, int toplevel, MMIOT *f)
 
 	    ptr = codeblock(p);
 	}
-#if WITH_FENCED_CODE
-	else if ( iscodefence(ptr,3,0) && (p=fencedcodeblock(&d, &ptr)) )
+	else if ( iscodefence(ptr,3,0,f->flags) && (p=fencedcodeblock(&d, &ptr, f->flags)) )
 	    /* yay, it's already done */ ;
-#endif
-	else if ( ishr(ptr) ) {
+	else if ( ishr(ptr, f->flags) ) {
 	    p = Pp(&d, 0, HR);
 	    r = ptr;
 	    ptr = ptr->next;
@@ -1279,7 +1279,7 @@ compile(Line *ptr, int toplevel, MMIOT *f)
 	    p->down = compile(p->text, 1, f);
 	    p->text = 0;
 	}
-	else if ( ishdr(ptr, &hdr_type) ) {
+	else if ( ishdr(ptr, &hdr_type, f->flags) ) {
 	    p = Pp(&d, ptr, HDR);
 	    ptr = headerblock(p, hdr_type);
 	}

markdown.h

@@ -131,6 +131,7 @@ typedef struct mmiot {
 #define MKD_NOSTYLE	0x00400000
 #define MKD_NODLDISCOUNT 0x00800000
 #define	MKD_DLEXTRA	0x01000000
+#define MKD_FENCEDCODE	0x02000000
 #define IS_LABEL	0x08000000
 #define USER_FLAGS	0x0FFFFFFF
 #define INPUT_MASK	(MKD_NOHEADER|MKD_TABSTOP)

mkdio.h.in

@@ -108,6 +108,7 @@ void mkd_ref_prefix(MMIOT*, char*);
 #define MKD_NOSTYLE	0x00400000	/* don't extract <style> blocks */
 #define MKD_NODLDISCOUNT 0x00800000	/* disable discount-style definition lists */
 #define	MKD_DLEXTRA	0x01000000	/* enable extra-style definition lists */
+#define MKD_FENCEDCODE	0x02000000	/* enabled fenced code blocks */
 
 #define MKD_EMBED	MKD_NOLINKS|MKD_NOIMAGE|MKD_TAGTEXT
 

pgm_options.c

@@ -57,6 +57,7 @@ static struct _opt {
     { "style",         "extract style blocks",       1, 0, 1, MKD_NOSTYLE },
     { "dldiscount",    "discount-style definition lists", 1, 0, 1, MKD_NODLDISCOUNT },
     { "dlextra",       "extra-style definition lists", 0, 0, 1, MKD_DLEXTRA },
+    { "fencedcode",    "fenced code blocks",         0, 0, 1, MKD_FENCEDCODE },
 } ;
 
 #define NR(x)	(sizeof x / sizeof x[0])