Added support for LaTeX math (#87) Addresses #86.
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diff --git a/md2html/md2html.c b/md2html/md2html.c
index 0d5b38b..a8e47a5 100644
--- a/md2html/md2html.c
+++ b/md2html/md2html.c
@@ -208,6 +208,7 @@ static const option cmdline_options[] = {
{ "fcollapse-whitespace", 0, 'W', OPTION_ARG_NONE },
{ "ftables", 0, 'T', OPTION_ARG_NONE },
{ "fstrikethrough", 0, 'S', OPTION_ARG_NONE },
+ { "flatex-math", 0, 'L', OPTION_ARG_NONE },
{ "ftasklists", 0, 'X', OPTION_ARG_NONE },
{ 0 }
};
@@ -256,6 +257,7 @@ usage(void)
" --fno-html Same as --fno-html-blocks --fno-html-spans\n"
" --ftables Enable tables\n"
" --fstrikethrough Enable strikethrough spans\n"
+ " --flatex-math Enable LaTeX style mathematics spans (e.g. $a+b=c$ becomes <equation>a+b=c</equation>)\n"
" --ftasklists Enable task lists\n"
);
}
@@ -304,6 +306,7 @@ cmdline_callback(int opt, char const* value, void* data)
case 'V': parser_flags |= MD_FLAG_PERMISSIVEAUTOLINKS; break;
case 'T': parser_flags |= MD_FLAG_TABLES; break;
case 'S': parser_flags |= MD_FLAG_STRIKETHROUGH; break;
+ case 'L': parser_flags |= MD_FLAG_LATEXMATHSPANS; break;
case 'X': parser_flags |= MD_FLAG_TASKLISTS; break;
default:
diff --git a/md2html/render_html.c b/md2html/render_html.c
index b8046e0..2442697 100644
--- a/md2html/render_html.c
+++ b/md2html/render_html.c
@@ -426,12 +426,14 @@ enter_span_callback(MD_SPANTYPE type, void* detail, void* userdata)
}
switch(type) {
- case MD_SPAN_EM: RENDER_LITERAL(r, "<em>"); break;
- case MD_SPAN_STRONG: RENDER_LITERAL(r, "<strong>"); break;
- 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;
+ case MD_SPAN_EM: RENDER_LITERAL(r, "<em>"); break;
+ case MD_SPAN_STRONG: RENDER_LITERAL(r, "<strong>"); break;
+ 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;
+ case MD_SPAN_LATEXMATH: RENDER_LITERAL(r, "<equation>"); break;
+ case MD_SPAN_LATEXMATH_DISPLAY: RENDER_LITERAL(r, "<equation type=\"display\">"); break;
}
return 0;
@@ -451,12 +453,14 @@ leave_span_callback(MD_SPANTYPE type, void* detail, void* userdata)
}
switch(type) {
- case MD_SPAN_EM: RENDER_LITERAL(r, "</em>"); break;
- case MD_SPAN_STRONG: RENDER_LITERAL(r, "</strong>"); break;
- 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;
+ case MD_SPAN_EM: RENDER_LITERAL(r, "</em>"); break;
+ case MD_SPAN_STRONG: RENDER_LITERAL(r, "</strong>"); break;
+ 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;
+ case MD_SPAN_LATEXMATH: /*fall through*/
+ case MD_SPAN_LATEXMATH_DISPLAY: RENDER_LITERAL(r, "</equation>"); break;
}
return 0;
diff --git a/md4c/md4c.c b/md4c/md4c.c
index d2b4313..6025659 100644
--- a/md4c/md4c.c
+++ b/md4c/md4c.c
@@ -127,7 +127,7 @@ struct MD_CTX_tag {
#endif
/* For resolving of inline spans. */
- MD_MARKCHAIN mark_chains[11];
+ MD_MARKCHAIN mark_chains[12];
#define PTR_CHAIN ctx->mark_chains[0]
#define TABLECELLBOUNDARIES ctx->mark_chains[1]
#define ASTERISK_OPENERS_extraword_mod3_0 ctx->mark_chains[2]
@@ -139,8 +139,9 @@ struct MD_CTX_tag {
#define UNDERSCORE_OPENERS ctx->mark_chains[8]
#define TILDE_OPENERS ctx->mark_chains[9]
#define BRACKET_OPENERS ctx->mark_chains[10]
+#define DOLLAR_OPENERS ctx->mark_chains[11]
#define OPENERS_CHAIN_FIRST 2
-#define OPENERS_CHAIN_LAST 10
+#define OPENERS_CHAIN_LAST 11
int n_table_cell_boundaries;
@@ -1128,7 +1129,7 @@ md_is_html_comment(MD_CTX* ctx, const MD_LINE* lines, int n_lines, OFF beg, OFF
if(off+1 < lines[0].end && CH(off) == _T('-') && CH(off+1) == _T('>'))
return FALSE;
- /* HTML comment must not contyain "--", so we scan just for "--" instead
+ /* HTML comment must not contain "--", so we scan just for "--" instead
* of "-->" and verify manually that '>' follows. */
if(md_scan_for_html_closer(ctx, _T("--"), 2,
lines, n_lines, off, max_end, p_end, &ctx->html_comment_horizon))
@@ -2683,6 +2684,9 @@ md_build_mark_char_map(MD_CTX* ctx)
if(ctx->parser.flags & MD_FLAG_STRIKETHROUGH)
ctx->mark_char_map['~'] = 1;
+ if(ctx->parser.flags & MD_FLAG_LATEXMATHSPANS)
+ ctx->mark_char_map['$'] = 1;
+
if(ctx->parser.flags & MD_FLAG_PERMISSIVEEMAILAUTOLINKS)
ctx->mark_char_map['@'] = 1;
@@ -3251,6 +3255,21 @@ md_collect_marks(MD_CTX* ctx, const MD_LINE* lines, int n_lines, int table_mode)
continue;
}
+ /* A potential equation start/end */
+ if(ch == _T('$')) {
+ /* We can have at most two consecutive $ signs,
+ * where two dollar signs signify a display equation. */
+ OFF tmp = off+1;
+
+ while(tmp < line_end && CH(tmp) == _T('$'))
+ tmp++;
+
+ if (tmp - off <= 2)
+ PUSH_MARK(ch, off, tmp, MD_MARK_POTENTIAL_OPENER | MD_MARK_POTENTIAL_CLOSER);
+ off = tmp;
+ continue;
+ }
+
/* Turn non-trivial whitespace into single space. */
if(ISWHITESPACE_(ch)) {
OFF tmp = off+1;
@@ -3631,6 +3650,36 @@ md_analyze_tilde(MD_CTX* ctx, int mark_index)
}
static void
+md_analyze_dollar(MD_CTX* ctx, int mark_index)
+{
+ /* This should mimic the way inline equations work in LaTeX, so there
+ * can only ever be one item in the chain (i.e. the dollars can't be
+ * nested). This is basically the same as the md_analyze_tilde function,
+ * except that we require matching openers and closers to be of the same
+ * length.
+ *
+ * E.g.: $abc$$def$$ => abc (display equation) def (end equation) */
+ if(DOLLAR_OPENERS.head >= 0) {
+ /* If the potential closer has a non-matching number of $, discard */
+ MD_MARK* open = &ctx->marks[DOLLAR_OPENERS.head];
+ MD_MARK* close = &ctx->marks[mark_index];
+
+ int opener_index = DOLLAR_OPENERS.head;
+ md_rollback(ctx, opener_index, mark_index, MD_ROLLBACK_ALL);
+ if (open->end - open->beg == close->end - close->beg) {
+ /* We are the matching closer */
+ md_resolve_range(ctx, &DOLLAR_OPENERS, opener_index, mark_index);
+ } else {
+ /* We don't match the opener, so discard old opener and insert as opener */
+ md_mark_chain_append(ctx, &DOLLAR_OPENERS, mark_index);
+ }
+ } else {
+ /* No unmatched openers, so we are opener */
+ md_mark_chain_append(ctx, &DOLLAR_OPENERS, mark_index);
+ }
+}
+
+static void
md_analyze_permissive_url_autolink(MD_CTX* ctx, int mark_index)
{
MD_MARK* opener = &ctx->marks[mark_index];
@@ -3785,6 +3834,7 @@ md_analyze_marks(MD_CTX* ctx, const MD_LINE* lines, int n_lines,
case '_': /* Pass through. */
case '*': md_analyze_emph(ctx, i); break;
case '~': md_analyze_tilde(ctx, i); break;
+ case '$': md_analyze_dollar(ctx, i); break;
case '.': /* Pass through. */
case ':': md_analyze_permissive_url_autolink(ctx, i); break;
case '@': md_analyze_permissive_email_autolink(ctx, i); break;
@@ -3841,7 +3891,7 @@ static void
md_analyze_link_contents(MD_CTX* ctx, const MD_LINE* lines, int n_lines,
int mark_beg, int mark_end)
{
- md_analyze_marks(ctx, lines, n_lines, mark_beg, mark_end, _T("*_~@:."));
+ md_analyze_marks(ctx, lines, n_lines, mark_beg, mark_end, _T("*_~$@:."));
ASTERISK_OPENERS_extraword_mod3_0.head = -1;
ASTERISK_OPENERS_extraword_mod3_0.tail = -1;
ASTERISK_OPENERS_extraword_mod3_1.head = -1;
@@ -3858,6 +3908,8 @@ md_analyze_link_contents(MD_CTX* ctx, const MD_LINE* lines, int n_lines,
UNDERSCORE_OPENERS.tail = -1;
TILDE_OPENERS.head = -1;
TILDE_OPENERS.tail = -1;
+ DOLLAR_OPENERS.head = -1;
+ DOLLAR_OPENERS.tail = -1;
}
static int
@@ -3974,6 +4026,16 @@ md_process_inlines(MD_CTX* ctx, const MD_LINE* lines, int n_lines)
MD_LEAVE_SPAN(MD_SPAN_DEL, NULL);
break;
+ case '$':
+ if(mark->flags & MD_MARK_OPENER) {
+ MD_ENTER_SPAN((mark->end - off) % 2 ? MD_SPAN_LATEXMATH : MD_SPAN_LATEXMATH_DISPLAY, NULL);
+ text_type = MD_TEXT_LATEXMATH;
+ } else {
+ MD_LEAVE_SPAN((mark->end - off) % 2 ? MD_SPAN_LATEXMATH : MD_SPAN_LATEXMATH_DISPLAY, NULL);
+ text_type = MD_TEXT_NORMAL;
+ }
+ break;
+
case '[': /* Link, image. */
case '!':
case ']':
@@ -4072,12 +4134,17 @@ md_process_inlines(MD_CTX* ctx, const MD_LINE* lines, int n_lines)
if(off >= end)
break;
- if(text_type == MD_TEXT_CODE) {
+ if(text_type == MD_TEXT_CODE || text_type == MD_TEXT_LATEXMATH) {
OFF tmp;
MD_ASSERT(prev_mark != NULL);
- MD_ASSERT(prev_mark->ch == '`' && (prev_mark->flags & MD_MARK_OPENER));
- MD_ASSERT(mark->ch == '`' && (mark->flags & MD_MARK_CLOSER));
+ if (text_type == MD_TEXT_CODE) {
+ MD_ASSERT(prev_mark->ch == '`' && (prev_mark->flags & MD_MARK_OPENER));
+ MD_ASSERT(mark->ch == '`' && (mark->flags & MD_MARK_CLOSER));
+ } else if (text_type == MD_TEXT_LATEXMATH) {
+ MD_ASSERT(prev_mark->ch == '$' && (prev_mark->flags & MD_MARK_OPENER));
+ MD_ASSERT(mark->ch == '$' && (mark->flags & MD_MARK_CLOSER));
+ }
/* Inside a code span, trailing line whitespace has to be
* outputted. */
@@ -4085,11 +4152,11 @@ md_process_inlines(MD_CTX* ctx, const MD_LINE* lines, int n_lines)
while(off < ctx->size && ISBLANK(off))
off++;
if(off > tmp)
- MD_TEXT(MD_TEXT_CODE, STR(tmp), off-tmp);
+ MD_TEXT(text_type, STR(tmp), off-tmp);
/* and new lines are transformed into single spaces. */
if(prev_mark->end < off && off < mark->beg)
- MD_TEXT(MD_TEXT_CODE, _T(" "), 1);
+ MD_TEXT(text_type, _T(" "), 1);
} else if(text_type == MD_TEXT_HTML) {
/* Inside raw HTML, we output the new line verbatim, including
diff --git a/md4c/md4c.h b/md4c/md4c.h
index dcdadad..6d9fce5 100644
--- a/md4c/md4c.h
+++ b/md4c/md4c.h
@@ -129,7 +129,13 @@ typedef enum MD_SPANTYPE {
/* <del>...</del>
* Note: Recognized only when MD_FLAG_STRIKETHROUGH is enabled.
*/
- MD_SPAN_DEL
+ MD_SPAN_DEL,
+
+ /* For recognizing inline ($) and display ($$) equations
+ * Note: Recognized only when MD_FLAG_LATEXMATHSPANS is enabled.
+ */
+ MD_SPAN_LATEXMATH,
+ MD_SPAN_LATEXMATH_DISPLAY
} MD_SPANTYPE;
/* Text is the actual textual contents of span. */
@@ -168,7 +174,11 @@ typedef enum MD_TEXTTYPE {
/* Text is a raw HTML. If it is contents of a raw HTML block (i.e. not
* an inline raw HTML), then MD_TEXT_BR and MD_TEXT_SOFTBR are not used.
* The text contains verbatim '\n' for the new lines. */
- MD_TEXT_HTML
+ MD_TEXT_HTML,
+
+ /* Text is inside an equation. This is processed the same way as inlined code
+ * spans (`code`). */
+ MD_TEXT_LATEXMATH
} MD_TEXTTYPE;
@@ -275,6 +285,7 @@ typedef struct MD_SPAN_IMG_DETAIL {
#define MD_FLAG_STRIKETHROUGH 0x0200 /* Enable strikethrough extension. */
#define MD_FLAG_PERMISSIVEWWWAUTOLINKS 0x0400 /* Enable WWW autolinks (even without any scheme prefix, if they begin with 'www.') */
#define MD_FLAG_TASKLISTS 0x0800 /* Enable task list extension. */
+#define MD_FLAG_LATEXMATHSPANS 0x1000 /* Enable $ and $$ containing LaTeX equations. */
#define MD_FLAG_PERMISSIVEAUTOLINKS (MD_FLAG_PERMISSIVEEMAILAUTOLINKS | MD_FLAG_PERMISSIVEURLAUTOLINKS | MD_FLAG_PERMISSIVEWWWAUTOLINKS)
#define MD_FLAG_NOHTML (MD_FLAG_NOHTMLBLOCKS | MD_FLAG_NOHTMLSPANS)
diff --git a/scripts/run-tests.sh b/scripts/run-tests.sh
index 7f5324f..b8e335b 100755
--- a/scripts/run-tests.sh
+++ b/scripts/run-tests.sh
@@ -59,5 +59,9 @@ echo "Task lists extension:"
$PYTHON "$TEST_DIR/spec_tests.py" -s "$TEST_DIR/tasklists.txt" -p "$PROGRAM --ftasklists"
echo
+echo "LaTeX extension:"
+$PYTHON "$TEST_DIR/spec_tests.py" -s "$TEST_DIR/latex.txt" -p "$PROGRAM --flatex-math"
+
+echo
echo "Pathological input:"
$PYTHON "$TEST_DIR/pathological_tests.py" -p "$PROGRAM"
diff --git a/test/latex.txt b/test/latex.txt
new file mode 100644
index 0000000..ed2b947
--- /dev/null
+++ b/test/latex.txt
@@ -0,0 +1,30 @@
+
+# LaTeX
+
+With the flag `MD_FLAG_LATEXMATHSPANS`, MD4C enables extension for recognition
+of LaTeX style equation spans.
+
+An equation is is any text wrapped in tildes ($ or $$).
+
+```````````````````````````````` example
+$a+b=c$ Hello, world!
+.
+<p><equation>a+b=c</equation> Hello, world!</p>
+````````````````````````````````
+
+If a double dollar sign is used, the equation is a display equation.
+
+```````````````````````````````` example
+This is a display equation: $$\int_a^b x dx$$.
+.
+<p>This is a display equation: <equation type="display">\int_a^b x dx</equation>.</p>
+````````````````````````````````
+
+Equations may span multiple lines.
+
+```````````````````````````````` example
+$$
+\int_a^b f(x) dx
+$$
+<p><equation type="display">\int_a^b f(x) dx </equation></p>
+````````````````````````````````