blob_append((blob), "" literal, (sizeof literal)-1)
  /*
   * The empty string in the second argument leads to a syntax error
   * when the macro is not used with a string literal. Unfortunately
   * the error is not overly explicit.
   */

/* BLOB_APPEND_BLOB -- append blob contents to another */
#define BLOB_APPEND_BLOB(dest, src) \
/* BLOB_APPEND_BLOB -- append blob contents to another
** TODO: Refactor all invocations to use globall macro blob_appendb()
*/
#define BLOB_APPEND_BLOB(dest, src) blob_appendb((dest), (src))
  blob_append((dest), blob_buffer(src), blob_size(src))

#ifndef FOOTNOTES_WITHOUT_URI
  #define BLOB_APPEND_URI(dest,ctx) BLOB_APPEND_BLOB(dest,&((ctx)->reqURI))
  #define BLOB_APPEND_URI(dest,ctx) blob_appendb(dest,&((ctx)->reqURI))
#else
  #define BLOB_APPEND_URI(dest,ctx)
#endif

/* Converts an integer to a null-terminated base26 representation
 * Return empty string if that integer is negative.   */
static bitfield64_t to_base26(int i, int uppercase){

    sprintf(pos, "%s-%i-%s", ctx->unique.c, iMark, l.c);
    if(span && blob_size(span)) {
      BLOB_APPEND_LITERAL(ob,"<span class='");
      append_footnote_upc(ob, upc, 0);
      BLOB_APPEND_LITERAL(ob,"notescope' id='noteref");
      blob_appendf(ob,"%s'>",pos);
      BLOB_APPEND_BLOB(ob, span);
      blob_appendb(ob, span);
      blob_trim(ob);
      BLOB_APPEND_LITERAL(ob,"<sup class='noteref'><a href='");
      BLOB_APPEND_URI(ob, ctx);
      blob_appendf(ob,"#footnote%s'>%i</a></sup></span>", pos, iMark);
    }else{
      blob_trim(ob);
      BLOB_APPEND_LITERAL(ob,"<sup class='");
      append_footnote_upc(ob, upc, 0);
      BLOB_APPEND_LITERAL(ob,"noteref'><a href='");
      BLOB_APPEND_URI(ob, ctx);
      blob_appendf(ob,"#footnote%s' id='noteref%s'>%i</a></sup>",
                      pos,           pos,  iMark);
    }
  }else{              /* misreference */
    assert( iMark == -1 );

    sprintf(pos, "%s-%s", ctx->unique.c, l.c);
    if(span && blob_size(span)) {
      blob_appendf(ob, "<span class='notescope' id='misref%s'>", pos);
      BLOB_APPEND_BLOB(ob, span);
      blob_appendb(ob, span);
      blob_trim(ob);
      BLOB_APPEND_LITERAL(ob, "<sup class='noteref misref'><a href='");
      BLOB_APPEND_URI(ob, ctx);
      blob_appendf(ob, "#misreference%s'>misref</a></sup></span>", pos);
    }else{
      blob_trim(ob);
      BLOB_APPEND_LITERAL(ob, "<sup class='noteref misref'><a href='");

    }
    BLOB_APPEND_LITERAL(ob,"</sup>\n");
    if( bJoin ){
      BLOB_APPEND_LITERAL(ob,"<sup class='fn-joined'></sup><ul>");
      blob_append(ob,blob_buffer(text)+_jfi_sz,blob_size(text)-_jfi_sz);
    }else if( nUsed ){
      append_footnote_upc(ob, upc, 1);
      BLOB_APPEND_BLOB(ob, text);
      blob_appendb(ob, text);
    }else{
      BLOB_APPEND_LITERAL(ob,"<i></i>\n"
          "<pre><code class='language-markdown'>");
      if( blob_size(upc) ){
        BLOB_APPEND_BLOB(ob, upc);
        blob_appendb(ob, upc);
      }
      html_escape(ob, blob_buffer(text), blob_size(text));
      BLOB_APPEND_LITERAL(ob,"</code></pre>");
    }
    #undef _joined_footnote_indicator
    #undef _jfi_sz
  }else{             /* a footnote was defined but wasn't referenced */
    /* make.footnote_item() invocations should pass args accordingly */
    const struct Blob * id = text-1;
    assert( !nUsed );
    assert( text );
    assert( blob_size(text) );
    assert( blob_size(id) );
    BLOB_APPEND_LITERAL(ob,"<li class='fn-unreferenced'>\n[^&nbsp;<code>");
    html_escape(ob, blob_buffer(id), blob_size(id));
    BLOB_APPEND_LITERAL(ob, "</code>&nbsp;]<i></i>\n"
        "<pre><code class='language-markdown'>");
    if( blob_size(upc) ){
      BLOB_APPEND_BLOB(ob, upc);
      blob_appendb(ob, upc);
    }
    html_escape(ob, blob_buffer(text), blob_size(text));
    BLOB_APPEND_LITERAL(ob,"</code></pre>");
  }
  BLOB_APPEND_LITERAL(ob, "\n</li>\n");
}
static void html_footnotes(
  struct Blob *ob, const struct Blob *items, void *opaque
){
  if( items && blob_size(items) ){
    BLOB_APPEND_LITERAL(ob,
      "\n<hr class='footnotes-separator'/>\n<ol class='footnotes'>\n");
    BLOB_APPEND_BLOB(ob, items);
    blob_appendb(ob, items);
    BLOB_APPEND_LITERAL(ob, "</ol>\n");
  }
}

/* HTML span tags */

static int html_raw_html_tag(struct Blob *ob, struct Blob *text, void *opaque){