commit 25a156ee1b21c7cb8d6cc82029c181fd15bccee8
parent d84dcec8f1e2f0b8d8b2086874637ace90dfb1e4
Author: Martin Mitas <mity@morous.org>
Date: Wed, 12 Jul 2017 23:30:14 +0200
Implement strikethrough extension.
Diffstat:
7 files changed, 104 insertions(+), 11 deletions(-)
diff --git a/README.md b/README.md
@@ -99,6 +99,9 @@ some extensions or allowing some deviations from the specification.
* With the flag `MD_FLAG_NOINDENTEDCODEBLOCKS`, indented code blocks are
disabled.
+ * With the flag `MD_FLAG_STRIKETHROUGH`, strikethrough spans are enabled
+ (text enclosed in tilde marks, e.g. '~foo bar~').
+
## Input/Output Encoding
diff --git a/md2html/md2html.c b/md2html/md2html.c
@@ -206,6 +206,7 @@ static const option cmdline_options[] = {
{ "fno-html", 0, 'H', OPTION_ARG_NONE },
{ "fcollapse-whitespace", 0, 'W', OPTION_ARG_NONE },
{ "ftables", 0, 'T', OPTION_ARG_NONE },
+ { "fstrikethrough", 0, 'S', OPTION_ARG_NONE },
{ 0 }
};
@@ -249,6 +250,7 @@ usage(void)
" Disable raw HTML spans\n"
" --fno-html Same as --fno-html-blocks --fno-html-spans\n"
" --ftables Enable tables\n"
+ " --fstrikethrough Enable strikethrough spans\n"
);
}
@@ -294,6 +296,7 @@ cmdline_callback(int opt, char const* value, void* data)
case '@': parser_flags |= MD_FLAG_PERMISSIVEEMAILAUTOLINKS; break;
case 'V': parser_flags |= MD_FLAG_PERMISSIVEAUTOLINKS; break;
case 'T': parser_flags |= MD_FLAG_TABLES; break;
+ case 'S': parser_flags |= MD_FLAG_STRIKETHROUGH; break;
default:
fprintf(stderr, "Illegal option: %s\n", value);
diff --git a/md2html/render_html.c b/md2html/render_html.c
@@ -410,6 +410,7 @@ enter_span_callback(MD_SPANTYPE type, void* detail, void* userdata)
case MD_SPAN_A: render_open_a_span(r, (MD_SPAN_A_DETAIL*) detail); break;
case MD_SPAN_IMG: render_open_img_span(r, (MD_SPAN_IMG_DETAIL*) detail); break;
case MD_SPAN_CODE: RENDER_LITERAL(r, "<code>"); break;
+ case MD_SPAN_DEL: RENDER_LITERAL(r, "<del>"); break;
}
return 0;
@@ -434,6 +435,7 @@ leave_span_callback(MD_SPANTYPE type, void* detail, void* userdata)
case MD_SPAN_A: RENDER_LITERAL(r, "</a>"); break;
case MD_SPAN_IMG: /*noop, handled above*/ break;
case MD_SPAN_CODE: RENDER_LITERAL(r, "</code>"); break;
+ case MD_SPAN_DEL: RENDER_LITERAL(r, "</del>"); break;
}
return 0;
diff --git a/md4c/md4c.c b/md4c/md4c.c
@@ -121,14 +121,15 @@ struct MD_CTX_tag {
#endif
/* For resolving of inline spans. */
- MD_MARKCHAIN mark_chains[7];
+ MD_MARKCHAIN mark_chains[8];
#define PTR_CHAIN ctx->mark_chains[0]
#define BACKTICK_OPENERS ctx->mark_chains[1]
#define LOWERTHEN_OPENERS ctx->mark_chains[2]
#define ASTERISK_OPENERS ctx->mark_chains[3]
#define UNDERSCORE_OPENERS ctx->mark_chains[4]
-#define BRACKET_OPENERS ctx->mark_chains[5]
-#define TABLECELLBOUNDARIES ctx->mark_chains[6]
+#define TILDE_OPENERS ctx->mark_chains[5]
+#define BRACKET_OPENERS ctx->mark_chains[6]
+#define TABLECELLBOUNDARIES ctx->mark_chains[7]
int n_table_cell_boundaries;
@@ -2131,6 +2132,8 @@ md_free_link_ref_defs(MD_CTX* ctx)
* '\\': Maybe escape sequence.
* '\0': NULL char.
* '*': Maybe (strong) emphasis start/end.
+ * '_': Maybe (strong) emphasis start/end.
+ * '~': Maybe strikethrough start/end (needs MD_FLAG_STRIKETHROUGH).
* '`': Maybe code span start/end.
* '&': Maybe start of entity.
* ';': Maybe end of entity.
@@ -2348,6 +2351,7 @@ md_rollback(MD_CTX* ctx, int opener_index, int closer_index, int how)
case '_': chain = &UNDERSCORE_OPENERS; break;
case '`': chain = &BACKTICK_OPENERS; break;
case '<': chain = &LOWERTHEN_OPENERS; break;
+ case '~': chain = &TILDE_OPENERS; break;
default: MD_UNREACHABLE(); break;
}
md_mark_chain_append(ctx, chain, mark_opener_index);
@@ -2395,6 +2399,9 @@ md_build_mark_char_map(MD_CTX* ctx)
ctx->mark_char_map[']'] = 1;
ctx->mark_char_map['\0'] = 1;
+ if(ctx->r.flags & MD_FLAG_STRIKETHROUGH)
+ ctx->mark_char_map['~'] = 1;
+
if(ctx->r.flags & MD_FLAG_PERMISSIVEURLAUTOLINKS)
ctx->mark_char_map[':'] = 1;
@@ -2653,6 +2660,17 @@ md_collect_marks(MD_CTX* ctx, const MD_LINE* lines, int n_lines, int table_mode)
continue;
}
+ /* A potential strikethrough start/end. */
+ if(ch == _T('~')) {
+ OFF tmp = off+1;
+
+ while(tmp < line_end && CH(tmp) == _T('~'))
+ tmp++;
+
+ PUSH_MARK(ch, off, tmp, MD_MARK_POTENTIAL_OPENER | MD_MARK_POTENTIAL_CLOSER);
+ off = tmp;
+ }
+
/* Turn non-trivial whitespace into single space. */
if(ISWHITESPACE_(ch)) {
OFF tmp = off+1;
@@ -3233,6 +3251,25 @@ md_analyze_underscore(MD_CTX* ctx, int mark_index)
}
static void
+md_analyze_tilde(MD_CTX* ctx, int mark_index)
+{
+ /* We attempt to be Github Flavored Markdown compatible here. GFM says
+ * that length of the tilde sequence is not important at all. Note that
+ * implies the TILDE_OPENERS chain can have at most one item. */
+
+ if(TILDE_OPENERS.head >= 0) {
+ /* The chain already contains an opener, so we may resolve the span. */
+ int opener_index = TILDE_OPENERS.head;
+
+ md_rollback(ctx, opener_index, mark_index, MD_ROLLBACK_CROSSING);
+ md_resolve_range(ctx, &TILDE_OPENERS, opener_index, mark_index);
+ } else {
+ /* We can only be opener. */
+ md_mark_chain_append(ctx, &TILDE_OPENERS, mark_index);
+ }
+}
+
+static void
md_analyze_permissive_url_autolink(MD_CTX* ctx, int mark_index)
{
MD_MARK* opener = &ctx->marks[mark_index];
@@ -3386,6 +3423,7 @@ md_analyze_marks(MD_CTX* ctx, const MD_LINE* lines, int n_lines, OFF beg, OFF en
case '|': md_analyze_table_cell_boundary(ctx, i); break;
case '*': md_analyze_asterisk(ctx, i); break;
case '_': md_analyze_underscore(ctx, i); break;
+ case '~': md_analyze_tilde(ctx, i); break;
case ':': md_analyze_permissive_url_autolink(ctx, i); break;
case '@': md_analyze_permissive_email_autolink(ctx, i); break;
}
@@ -3434,11 +3472,7 @@ md_analyze_inlines(MD_CTX* ctx, const MD_LINE* lines, int n_lines, int table_mod
md_analyze_marks(ctx, lines, n_lines, beg, end, _T("|"));
} else {
/* (3b) Emphasis and strong emphasis; permissive autolinks. */
- md_analyze_marks(ctx, lines, n_lines, beg, end, _T("*_@:"));
- ASTERISK_OPENERS.head = -1;
- ASTERISK_OPENERS.tail = -1;
- UNDERSCORE_OPENERS.head = -1;
- UNDERSCORE_OPENERS.tail = -1;
+ md_analyze_link_contents(ctx, lines, n_lines, beg, end);
}
abort:
@@ -3448,11 +3482,13 @@ abort:
static void
md_analyze_link_contents(MD_CTX* ctx, const MD_LINE* lines, int n_lines, OFF beg, OFF end)
{
- md_analyze_marks(ctx, lines, n_lines, beg, end, _T("*_@:"));
+ md_analyze_marks(ctx, lines, n_lines, beg, end, _T("*_~@:"));
ASTERISK_OPENERS.head = -1;
ASTERISK_OPENERS.tail = -1;
UNDERSCORE_OPENERS.head = -1;
UNDERSCORE_OPENERS.tail = -1;
+ TILDE_OPENERS.head = -1;
+ TILDE_OPENERS.tail = -1;
}
static int
@@ -3558,6 +3594,13 @@ md_process_inlines(MD_CTX* ctx, const MD_LINE* lines, int n_lines)
}
break;
+ case '~':
+ if(mark->flags & MD_MARK_OPENER)
+ MD_ENTER_SPAN(MD_SPAN_DEL, NULL);
+ else
+ MD_LEAVE_SPAN(MD_SPAN_DEL, NULL);
+ break;
+
case '[': /* Link, image. */
case '!':
case ']':
diff --git a/md4c/md4c.h b/md4c/md4c.h
@@ -126,7 +126,12 @@ typedef enum MD_SPANTYPE {
MD_SPAN_IMG,
/* <code>...</code> */
- MD_SPAN_CODE
+ MD_SPAN_CODE,
+
+ /* <del>...</del>
+ * Note: Recognized only when MD_FLAG_STRIKETHROUGH is enabled.
+ */
+ MD_SPAN_DEL
} MD_SPANTYPE;
/* Text is the actual textual contents of span. */
@@ -263,6 +268,7 @@ typedef struct MD_SPAN_IMG_DETAIL {
#define MD_FLAG_NOHTMLSPANS 0x0040 /* Disable raw HTML (inline). */
#define MD_FLAG_NOHTML (MD_FLAG_NOHTMLBLOCKS | MD_FLAG_NOHTMLSPANS)
#define MD_FLAG_TABLES 0x0100 /* Enable tables extension. */
+#define MD_FLAG_STRIKETHROUGH 0x0200 /* Enable strikethrough extension. */
/* Convenient sets of flags corresponding to well-known Markdown dialects.
* Note we may only support subset of features of the referred dialect.
@@ -270,7 +276,7 @@ typedef struct MD_SPAN_IMG_DETAIL {
* possible given what features we implement.
*/
#define MD_DIALECT_COMMONMARK 0
-#define MD_DIALECT_GITHUB (MD_FLAG_PERMISSIVEAUTOLINKS | MD_FLAG_TABLES)
+#define MD_DIALECT_GITHUB (MD_FLAG_PERMISSIVEAUTOLINKS | MD_FLAG_TABLES | MD_FLAG_STRIKETHROUGH)
/* Renderer structure.
*/
diff --git a/scripts/run-tests.sh b/scripts/run-tests.sh
@@ -35,3 +35,4 @@ $PYTHON "$TEST_DIR/spec_tests.py" -s "$TEST_DIR/coverage.txt" -p "$PROGRAM"
$PYTHON "$TEST_DIR/spec_tests.py" -s "$TEST_DIR/permissive-email-autolinks.txt" -p "$PROGRAM --fpermissive-email-autolinks"
$PYTHON "$TEST_DIR/spec_tests.py" -s "$TEST_DIR/permissive-url-autolinks.txt" -p "$PROGRAM --fpermissive-url-autolinks"
$PYTHON "$TEST_DIR/spec_tests.py" -s "$TEST_DIR/tables.txt" -p "$PROGRAM --ftables"
+$PYTHON "$TEST_DIR/spec_tests.py" -s "$TEST_DIR/strikethrough.txt" -p "$PROGRAM --fstrikethrough"
diff --git a/test/strikethrough.txt b/test/strikethrough.txt
@@ -0,0 +1,34 @@
+
+# Strikethrough
+
+With the flag `MD_FLAG_STRIKETHROUGH`, MD4C enables extension for recognition
+of strike-through spans.
+
+Strikethrough text is any text wrapped in tildes (~).
+
+```````````````````````````````` example
+~Hi~ Hello, world!
+.
+<p><del>Hi</del> Hello, world!</p>
+````````````````````````````````
+
+Any number of tildes may be used on either side of the text; they do not need
+to match, and they cannot be nested.
+
+```````````````````````````````` example
+This ~text~~~~ is ~~~~curious~.
+.
+<p>This <del>text</del> is <del>curious</del>.</p>
+````````````````````````````````
+
+As with regular emphasis delimiters, a new paragraph will cause the cessation
+of parsing a strikethrough:
+
+```````````````````````````````` example
+This ~~has a
+
+new paragraph~~.
+.
+<p>This ~~has a</p>
+<p>new paragraph~~.</p>
+````````````````````````````````+
\ No newline at end of file
