diff --git a/Makefile.in b/Makefile.in index 843e479..9345818 100644 --- a/Makefile.in +++ b/Makefile.in @@ -22,12 +22,15 @@ install: $(PGM) # @INSTALL_DIR@ $(MANDIR)/man3 # @INSTALL_DATA@ markdown.3 mkdio.3 $(MANDIR)/man3 -version.o: VERSION +version.o: VERSION config.h echo 'char version[] = VERSION;' > version.c && \ $(CC) -DVERSION=\"`cat VERSION`\" -c version.c -$(PGM): main.c version.o $(MKDLIB) - $(CC) -L. -I. -o $(PGM) main.c version.o -lmarkdown @LIBS@ +$(PGM): main.o version.o $(MKDLIB) + $(CC) -L. -o $(PGM) main.o version.o -lmarkdown @LIBS@ + +main.o: main.c mkdio.h config.h + $(CC) -I. -c main.c $(MKDLIB): $(OBJS) $(AR) crv $(MKDLIB) $(OBJS) @@ -41,5 +44,4 @@ distclean spotless: clean markdown.o: markdown.c config.h cstring.h -mkdio.o: mkdio.c mkdio.h cstring.h -$(PGM): mkdio.h config.h +mkdio.o: mkdio.c mkdio.h cstring.h config.h diff --git a/cstring.h b/cstring.h index 4d361dc..b4f68fe 100644 --- a/cstring.h +++ b/cstring.h @@ -20,7 +20,7 @@ : !((x).text = realloc((x).text, sizeof T(x)[0] * ((x).alloc += 100)))), \ (x).size++] -#define DELETE(x) (x).alloc ? (free(T(x)), S(x) x.alloc = 0) \ +#define DELETE(x) (x).alloc ? (free(T(x)), S(x) = (x).alloc = 0) \ : ( S(x) = 0 ) #define CLIP(t,i,sz) \ ( ((i) >= 0) && ((sz) > 0) && (((i)+(sz)) <= S(t)) ) ? \ diff --git a/main.c b/main.c index 6cb3f73..1f4950b 100644 --- a/main.c +++ b/main.c @@ -2,6 +2,7 @@ #include #include +float main(int argc, char **argv) { diff --git a/markdown.c b/markdown.c index 536b109..d492260 100644 --- a/markdown.c +++ b/markdown.c @@ -1,10 +1,16 @@ /* markdown: a C implementation of John Gruber's Markdown markup language. + * + * Copyright (C) 2007 David L Parsons. + * The redistribution terms are provided in the COPYRIGHT file that must + * be distributed with this source code. */ #include #include #include #include #include +#include + #include "cstring.h" #include "markdown.h" @@ -20,8 +26,12 @@ static char *blocktags[] = { "ADDRESS", "BDO", "BLOCKQUOTE", "CENTER", "H5", "H6", "LISTING", "NOBR", "UL", "P", "OL", "DL", "PLAINTEXT", "PRE", "WBR", "XMP" }; -#define SZBLOCKTAGS (sizeof blocktags / sizeof blocktags[0]) +#define SZTAGS (sizeof blocktags / sizeof blocktags[0]) +static STRING(Footnote) footnotes; + + +typedef int (*stfu)(const void*,const void*); /* case insensitive string sort (for qsort() and bsearch() of block tags) */ @@ -47,7 +57,7 @@ footsort(Footnote *a, Footnote *b) static char * isblocktag(char *tag) { - char **r=bsearch(&tag, blocktags, SZBLOCKTAGS, sizeof blocktags[0], casort); + char **r=bsearch(&tag, blocktags, SZTAGS, sizeof blocktags[0], (stfu)casort); return r ? (*r) : 0; } @@ -87,7 +97,7 @@ mkd_firstnonblank(Line *p) static Cstring output; static unsigned int csp = 0; -static int +static void push(char *t, int s) { int i; @@ -183,7 +193,6 @@ linkylinky(int image, FILE *out) skipblankc(); if ( image && (peek(1) == '=') ) { - char *dim; int width, height; pull(); @@ -227,7 +236,8 @@ linkylinky(int image, FILE *out) } T(key.tag) = tag; - ret = bsearch(&key, T(footnotes), S(footnotes), sizeof key, footsort); + ret = bsearch(&key, T(footnotes), S(footnotes), + sizeof key, (stfu)footsort); if ( ret ) { if ( S(ret->link) ) @@ -245,19 +255,26 @@ linkylinky(int image, FILE *out) } -static char* -hexfmt() +static void +mangle(unsigned char *s, int len, FILE *out) { - return (random()&1) ? "&#x%02x;" : "&#%02d;"; + while ( len-- > 0 ) + fprintf(out, (random()&1) ? "&#x%02x;" : "&#%02d;", *s++); } +/* a < may be just a regular character, the start of an embedded html + * tag, or the start of an . If it's an automatic + * link, we also need to know if it's an email address because if it + * is we need to mangle it in our futile attempt to cut down on the + * spaminess of the rendered page. + */ static int -handle_less_than(FILE *out) +maybe_tag_or_link(FILE *out) { char *text; int c, size, i; - int maybetag=1, maybelink=0, maybeaddress=0; + int maybetag=1, maybeaddress=0; for ( size=0; ((c = peek(size+1)) != '>') && !isspace(c); size++ ) { if ( ! (c == '/' || isalnum(c) || c == '~') ) @@ -285,20 +302,18 @@ handle_less_than(FILE *out) return 1; } if ( maybeaddress ) { - fprintf(out, "<"); - for ( i=0; i < size; i++ ) - fprintf(out,hexfmt(), (unsigned char)text[i]); + mangle(text, size, out); fprintf(out,""); return 1; } - fprintf(out,"<"); shift(-size); - return 1; -} + return 0; +} /* maybe_tag_or_link */ static int @@ -310,18 +325,80 @@ isthisblank(i) } +/* Smarty-pants-style chrome for quotes, -, ellipses, and (r)(c)(tm) + */ +static int +smartypants(int c, int *flags, FILE *out) +{ + int squo, dquo; + + switch (c) { + case '"': dquo = 0x01 & (*flags); + if ( isthisblank ( dquo ? 1 : -1 ) ) { + fprintf(out, "&%cdquo;", dquo ? 'r' : 'l' ); + (*flags) ^= 0x01; + return 1; + } + break; + + case '\'': squo = 0x02 & (*flags); + if ( isthisblank( squo ? 1 : -1 ) ) { + fprintf(out, "&%csquo;", squo ? 'r' : 'l' ); + (*flags) ^= 0x02; + return 1; + } + break; + + case '.': if ( peek(1) == '.' && peek(2) == '.' ) { + fprintf(out,"…"); + shift(2); + return 1; + } + break; + + case '-': if ( peek(1) == '-' ) { + fprintf(out, "—"); + pull(); + return 1; + } + else if ( isspace(peek(-1)) && isspace(peek(1)) ) { + fprintf(out, "–"); + return 1; + } + break; + + case '(': c = toupper(peek(1)); + if ( (c == 'C' || c == 'R') && (peek(2) == ')') ) { + fprintf(out, "&%s;", (c=='C') ? "copy" : "reg" ); + shift(2); + return 1; + } + else if ( (c == 'T') && (toupper(peek(2)) == 'M') + && (peek(3) == ')') ) { + fprintf(out, "™"); + shift(3); + return 1; + } + break; + } + return 0; +} /* smartypants */ + + static void code(int, FILE*); + static void text(FILE *out) { int c, j; int em = 0; int strong = 0; - int dquo = 0; - int squo = 0; + int smartyflags = 0; while ( (c = pull()) != EOF ) { + if (smartypants(c, &smartyflags, out)) + continue; switch (c) { case 0: break; @@ -374,6 +451,7 @@ text(FILE *out) } else code(1, out); + fprintf(out, ""); break; case '\\': if ( (c = pull()) == '&' ) @@ -384,8 +462,7 @@ text(FILE *out) fputc( c ? c : '\\', out); break; - case '<': if ( !handle_less_than(out) ) - fprintf(out, "<"); + case '<': maybe_tag_or_link(out) || fprintf(out, "<"); break; case '&': j = (peek(1) == '#' ) ? 2 : 1; @@ -400,86 +477,35 @@ text(FILE *out) default: fputc(c, out); break; - -/* Smarty-pants-style chrome for quotes, -, ellipses, and (r)(c)(tm) - */ - case '"': fprintf(out, "&%cdquo;", dquo ? 'r' : 'l' ); - dquo = !dquo; - break; - - case '\'': if ( isthisblank( squo ? 1 : -1 ) ) { - fprintf(out, "&%csquo;", squo ? 'r' : 'l' ); - squo = !squo; - } - else - fputc(c,out); - break; - break; - - case '.': if ( peek(1) == '.' && peek(2) == '.' ) { - fprintf(out,"…"); - pull();pull(); - } - else - fputc(c, out); - break; - - case '-': if ( peek(1) == '-' ) { - fprintf(out, "—"); - pull(); - } - else if ( isspace(peek(-1)) && isspace(peek(1)) ) - fprintf(out, "–"); - else - fputc(c, out); - break; - - case '(': if ( (j = toupper(peek(1))) == 'R' || j == 'C' ) { - if ( peek(2) == ')' ) { - fprintf(out, "&%s;", (j=='C') ? "copy" : "reg" ); - pull();pull(); - break; - } - } - else if ( j == 'T' && toupper(peek(2)) == 'M' - && peek(3) == ')' ) { - fprintf(out, "™"); - pull();pull();pull(); - break; - } - fputc(c, out); - break; } } if ( em ) fputs("", out); if ( strong ) fputs("", out); -} +} /* text */ +/* the only characters that have special meaning in a code block are + * `<' and `&' , which are /always/ expanded to < and & + */ static void code(int escape, FILE *out) { - int c, j; + int c; while ( (c = pull()) != EOF ) { switch (c) { - case '`': switch (escape) { - case 2: if ( peek(1) == '`' ) { - pull(); - case 1: fprintf(out, ""); - return; - } - } - fputc(c, out); - break; - case '&': fprintf(out, "&"); break; case '<': fprintf(out, "<"); break; + case '`': switch (escape) { + case 2: if ( peek(1) == '`' ) { + shift(1); + case 1: return; + } + } default: fputc(c, out); break; } } - fprintf(out, ""); -} +} /* code */ /* setext header; 2 lines, second is ==== or ----- @@ -609,9 +635,9 @@ static Paragraph *display(Paragraph*, FILE*, int); static void emit(Paragraph *p, FILE *out) { - int multiple = p->next; + int multiple = ( p->next != 0 ); - while ( p = display(p, out, multiple) ) + while (( p = display(p, out, multiple) )) ; } @@ -636,13 +662,6 @@ listdisplay(Paragraph *p, FILE* out) } -static int -nextislist(Paragraph *p) -{ - return p && (p->typ == UL || p->typ == OL); -} - - /* dump out a Paragraph in the desired manner */ static Paragraph* @@ -982,7 +1001,7 @@ static Line * listblock(Paragraph *p, int trim) { Line *t = p->text; - Line *first = t, *blank, *last = 0; + Line *last = 0; do { if ( last ) { @@ -1112,7 +1131,7 @@ compile(Line *ptr, int toplevel) char *key; int list_type, indent; - while ( ptr = skipempty(ptr) ) { + while (( ptr = skipempty(ptr) )) { if ( toplevel && (key = isopentag(ptr)) ) { p = Pp(&d, ptr, HTML, 0); ptr = htmlblock(p, key); @@ -1125,7 +1144,7 @@ compile(Line *ptr, int toplevel) p = Pp(&d, 0, HR, 0); ptr = ptr->next; } - else if ( list_type = islist(ptr, &indent) ) { + else if (( list_type = islist(ptr, &indent) )) { p = Pp(&d, ptr, list_type, 0); ptr = listblock(p, indent); @@ -1161,8 +1180,6 @@ freeLine(Line *p) static void freeParagraph(Paragraph *p) { - Line *t; - if (p->next) freeParagraph(p->next); if (p->down) freeParagraph(p->down); else if (p->text) freeLine(p->text); @@ -1176,9 +1193,9 @@ freefootnotes() int i; for (i=0; i < S(footnotes); i++) { - free(T(T(footnotes)[i].tag)); - free(T(T(footnotes)[i].link)); - free(T(T(footnotes)[i].title)); + DELETE(T(footnotes)[i].tag); + DELETE(T(footnotes)[i].link); + DELETE(T(footnotes)[i].title); } S(footnotes) = 0; } @@ -1192,7 +1209,7 @@ initmarkdown() if ( init ) return; srandom((unsigned int)time(0)); - qsort(blocktags, SZBLOCKTAGS, sizeof blocktags[0], casort); + qsort(blocktags, SZTAGS, sizeof blocktags[0], (stfu)casort); CREATE(footnotes); CREATE(output); init = 1; @@ -1206,7 +1223,7 @@ markdown(Line *text, FILE *out, int flags) initmarkdown(); paragraph = compile(text, 1); - qsort(T(footnotes), S(footnotes), sizeof T(footnotes)[0], footsort); + qsort(T(footnotes), S(footnotes), sizeof T(footnotes)[0], (stfu)footsort); emit(paragraph, out); diff --git a/markdown.h b/markdown.h index 7c2eedf..f918c51 100644 --- a/markdown.h +++ b/markdown.h @@ -13,8 +13,6 @@ typedef struct footnote { int height, width; /* dimensions (for image link) */ } Footnote; -static STRING(Footnote) footnotes; - /* each input line is read into a Line, which contains the line, * the offset of the first non-space character [this assumes * that all tabs will be expanded to spaces!], and a pointer to diff --git a/mkdio.c b/mkdio.c index 160b934..709ea51 100644 --- a/mkdio.c +++ b/mkdio.c @@ -1,3 +1,10 @@ +/* + * mkdio -- markdown front end input functions + * + * Copyright (C) 2007 David L Parsons. + * The redistribution terms are provided in the COPYRIGHT file that must + * be distributed with this source code. + */ #include "config.h" #include #include @@ -73,26 +80,52 @@ mkd_close(LineAnchor *p) Line * mkd_in(FILE *input) { - int i, c, xp; - Line *p; - static Cstring line = { 0, 0 }; + int c; + Cstring line; LineAnchor *a = mkd_open(); if ( !a ) return 0; + CREATE(line); for (; (c = getc(input)) != EOF; ) { if (c == '\n') { - xp = 0; mkd_write(a, T(line), S(line)); S(line) = 0; } else { EXPAND(line) = c; - xp++; } } - if ( xp ) + if ( S(line) ) mkd_write(a, T(line), S(line)); + DELETE(line); + return mkd_close(a); +} + + +/* convert a block of text into a linked list + */ +Line * +mkd_string(char *buf, int len) +{ + Cstring line; + LineAnchor *a = mkd_open(); + + if ( !a ) return 0; + + CREATE(line); + for ( ; len-- > 0; ++buf ) { + if ( *buf == '\n' ) { + mkd_write(a, T(line), S(line)); + S(line) = 0; + } + else + EXPAND(line) = *buf; + } + if ( S(line) ) + mkd_write(a, T(line), S(line)); + + DELETE(line); return mkd_close(a); } diff --git a/mkdio.h b/mkdio.h index 6b73406..9cb2133 100644 --- a/mkdio.h +++ b/mkdio.h @@ -7,7 +7,8 @@ void *mkd_open(); /* open a mkdio input assembler */ int mkd_write(void*, char*, int); /* write text into the assembler */ void *mkd_close(void*); /* get the assembled input */ -void *mkd_in(FILE*); /* get assembled input from a file */ +void *mkd_in(FILE*); /* assemble input from a file */ +void *mkd_string(char*,int); /* assemble input from a buffer */ void markdown(void*, FILE*, int); /* mark it on down */ diff --git a/tests/chrome.text b/tests/chrome.text new file mode 100644 index 0000000..d97b47b --- /dev/null +++ b/tests/chrome.text @@ -0,0 +1,13 @@ +->###chrome with my markdown###<- + +1. `(c)` -> `©` (c) +2. `(r)` -> `®` (r) +3. `(tm)` -> `™` (tm) +4. `...` -> `…` ... +5. `--` -> `&emdash;` -- +6. `-` -> `–` - (but not if it's between-words) +7. "fancy quoting" +8. 'fancy quoting (#2)' +9. don't do it unless it's a real quote. +10. `` (`) `` + diff --git a/tests/links.text b/tests/links.text new file mode 100644 index 0000000..ca40439 --- /dev/null +++ b/tests/links.text @@ -0,0 +1,14 @@ + 1. + 2. [automatic] (http://automatic "automatic link") + 3. [automatic](http://automatic "automatic link") + 4. [automatic](http://automatic) + 5. [automatic] (http://automatic) + 6. [automatic] [] + 7. [automatic][] + 8. [my][automatic] + 9. [my] [automatic] + + [automatic]: http://automatic "footnote" + + + [automatic] [ diff --git a/tests/syntax.text b/tests/syntax.text new file mode 100644 index 0000000..df740dd --- /dev/null +++ b/tests/syntax.text @@ -0,0 +1,897 @@ +Markdown: Syntax +================ + + + + +* [Overview](#overview) + * [Philosophy](#philosophy) + * [Inline HTML](#html) + * [Automatic Escaping for Special Characters](#autoescape) +* [Block Elements](#block) + * [Paragraphs and Line Breaks](#p) + * [Headers](#header) + * [Blockquotes](#blockquote) + * [Lists](#list) + * [Code Blocks](#precode) + * [Horizontal Rules](#hr) +* [Span Elements](#span) + * [Links](#link) + * [Emphasis](#em) + * [Code](#code) + * [Images](#img) +* [Miscellaneous](#misc) + * [Backslash Escapes](#backslash) + * [Automatic Links](#autolink) + + +**Note:** This document is itself written using Markdown; you +can [see the source for it by adding '.text' to the URL][src]. + + [src]: /projects/markdown/syntax.text + +* * * + +

Overview

+ +

Philosophy

+ +Markdown is intended to be as easy-to-read and easy-to-write as is feasible. + +Readability, however, is emphasized above all else. A Markdown-formatted +document should be publishable as-is, as plain text, without looking +like it's been marked up with tags or formatting instructions. While +Markdown's syntax has been influenced by several existing text-to-HTML +filters -- including [Setext] [1], [atx] [2], [Textile] [3], [reStructuredText] [4], +[Grutatext] [5], and [EtText] [6] -- the single biggest source of +inspiration for Markdown's syntax is the format of plain text email. + + [1]: http://docutils.sourceforge.net/mirror/setext.html + [2]: http://www.aaronsw.com/2002/atx/ + [3]: http://textism.com/tools/textile/ + [4]: http://docutils.sourceforge.net/rst.html + [5]: http://www.triptico.com/software/grutatxt.html + [6]: http://ettext.taint.org/doc/ + +To this end, Markdown's syntax is comprised entirely of punctuation +characters, which punctuation characters have been carefully chosen so +as to look like what they mean. E.g., asterisks around a word actually +look like \*emphasis\*. Markdown lists look like, well, lists. Even +blockquotes look like quoted passages of text, assuming you've ever +used email. + + + +

Inline HTML

+ +Markdown's syntax is intended for one purpose: to be used as a +format for *writing* for the web. + +Markdown is not a replacement for HTML, or even close to it. Its +syntax is very small, corresponding only to a very small subset of +HTML tags. The idea is *not* to create a syntax that makes it easier +to insert HTML tags. In my opinion, HTML tags are already easy to +insert. The idea for Markdown is to make it easy to read, write, and +edit prose. HTML is a *publishing* format; Markdown is a *writing* +format. Thus, Markdown's formatting syntax only addresses issues that +can be conveyed in plain text. + +For any markup that is not covered by Markdown's syntax, you simply +use HTML itself. There's no need to preface it or delimit it to +indicate that you're switching from Markdown to HTML; you just use +the tags. + +The only restrictions are that block-level HTML elements -- e.g. `
`, +``, `
`, `
`, etc. -- must be separated from surrounding
+content by blank lines, and the start and end tags of the block should
+not be indented with tabs or spaces. Markdown is smart enough not
+to add extra (unwanted) `
` tags around HTML block-level tags.
+
+For example, to add an HTML table to a Markdown article:
+
+    This is a regular paragraph.
+
+
+ + + +
Foo
+ + This is another regular paragraph. + +Note that Markdown formatting syntax is not processed within block-level +HTML tags. E.g., you can't use Markdown-style `*emphasis*` inside an +HTML block. + +Span-level HTML tags -- e.g. ``, ``, or `` -- can be +used anywhere in a Markdown paragraph, list item, or header. If you +want, you can even use HTML tags instead of Markdown formatting; e.g. if +you'd prefer to use HTML `` or `` tags instead of Markdown's +link or image syntax, go right ahead. + +Unlike block-level HTML tags, Markdown syntax *is* processed within +span-level tags. + + +

Automatic Escaping for Special Characters

+ +In HTML, there are two characters that demand special treatment: `<` +and `&`. Left angle brackets are used to start tags; ampersands are +used to denote HTML entities. If you want to use them as literal +characters, you must escape them as entities, e.g. `<`, and +`&`. + +Ampersands in particular are bedeviling for web writers. If you want to +write about 'AT&T', you need to write '`AT&T`'. You even need to +escape ampersands within URLs. Thus, if you want to link to: + + http://images.google.com/images?num=30&q=larry+bird + +you need to encode the URL as: + + http://images.google.com/images?num=30&q=larry+bird + +in your anchor tag `href` attribute. Needless to say, this is easy to +forget, and is probably the single most common source of HTML validation +errors in otherwise well-marked-up web sites. + +Markdown allows you to use these characters naturally, taking care of +all the necessary escaping for you. If you use an ampersand as part of +an HTML entity, it remains unchanged; otherwise it will be translated +into `&`. + +So, if you want to include a copyright symbol in your article, you can write: + + © + +and Markdown will leave it alone. But if you write: + + AT&T + +Markdown will translate it to: + + AT&T + +Similarly, because Markdown supports [inline HTML](#html), if you use +angle brackets as delimiters for HTML tags, Markdown will treat them as +such. But if you write: + + 4 < 5 + +Markdown will translate it to: + + 4 < 5 + +However, inside Markdown code spans and blocks, angle brackets and +ampersands are *always* encoded automatically. This makes it easy to use +Markdown to write about HTML code. (As opposed to raw HTML, which is a +terrible format for writing about HTML syntax, because every single `<` +and `&` in your example code needs to be escaped.) + + +* * * + + +

Block Elements

+ + +

Paragraphs and Line Breaks

+ +A paragraph is simply one or more consecutive lines of text, separated +by one or more blank lines. (A blank line is any line that looks like a +blank line -- a line containing nothing but spaces or tabs is considered +blank.) Normal paragraphs should not be indented with spaces or tabs. + +The implication of the "one or more consecutive lines of text" rule is +that Markdown supports "hard-wrapped" text paragraphs. This differs +significantly from most other text-to-HTML formatters (including Movable +Type's "Convert Line Breaks" option) which translate every line break +character in a paragraph into a `
` tag. + +When you *do* want to insert a `
` break tag using Markdown, you +end a line with two or more spaces, then type return. + +Yes, this takes a tad more effort to create a `
`, but a simplistic +"every line break is a `
`" rule wouldn't work for Markdown. +Markdown's email-style [blockquoting][bq] and multi-paragraph [list items][l] +work best -- and look better -- when you format them with hard breaks. + + [bq]: #blockquote + [l]: #list + + + + + +Markdown supports two styles of headers, [Setext] [1] and [atx] [2]. + +Setext-style headers are "underlined" using equal signs (for first-level +headers) and dashes (for second-level headers). For example: + + This is an H1 + ============= + + This is an H2 + ------------- + +Any number of underlining `=`'s or `-`'s will work. + +Atx-style headers use 1-6 hash characters at the start of the line, +corresponding to header levels 1-6. For example: + + # This is an H1 + + ## This is an H2 + + ###### This is an H6 + +Optionally, you may "close" atx-style headers. This is purely +cosmetic -- you can use this if you think it looks better. The +closing hashes don't even need to match the number of hashes +used to open the header. (The number of opening hashes +determines the header level.) : + + # This is an H1 # + + ## This is an H2 ## + + ### This is an H3 ###### + + +

Blockquotes

+ +Markdown uses email-style `>` characters for blockquoting. If you're +familiar with quoting passages of text in an email message, then you +know how to create a blockquote in Markdown. It looks best if you hard +wrap the text and put a `>` before every line: + + > This is a blockquote with two paragraphs. Lorem ipsum dolor sit amet, + > consectetuer adipiscing elit. Aliquam hendrerit mi posuere lectus. + > Vestibulum enim wisi, viverra nec, fringilla in, laoreet vitae, risus. + > + > Donec sit amet nisl. Aliquam semper ipsum sit amet velit. Suspendisse + > id sem consectetuer libero luctus adipiscing. + +Markdown allows you to be lazy and only put the `>` before the first +line of a hard-wrapped paragraph: + + > This is a blockquote with two paragraphs. Lorem ipsum dolor sit amet, + consectetuer adipiscing elit. Aliquam hendrerit mi posuere lectus. + Vestibulum enim wisi, viverra nec, fringilla in, laoreet vitae, risus. + + > Donec sit amet nisl. Aliquam semper ipsum sit amet velit. Suspendisse + id sem consectetuer libero luctus adipiscing. + +Blockquotes can be nested (i.e. a blockquote-in-a-blockquote) by +adding additional levels of `>`: + + > This is the first level of quoting. + > + > > This is nested blockquote. + > + > Back to the first level. + +Blockquotes can contain other Markdown elements, including headers, lists, +and code blocks: + + > ## This is a header. + > + > 1. This is the first list item. + > 2. This is the second list item. + > + > Here's some example code: + > + > return shell_exec("echo $input | $markdown_script"); + +Any decent text editor should make email-style quoting easy. For +example, with BBEdit, you can make a selection and choose Increase +Quote Level from the Text menu. + + +

Lists

+ +Markdown supports ordered (numbered) and unordered (bulleted) lists. + +Unordered lists use asterisks, pluses, and hyphens -- interchangably +-- as list markers: + + * Red + * Green + * Blue + +is equivalent to: + + + Red + + Green + + Blue + +and: + + - Red + - Green + - Blue + +Ordered lists use numbers followed by periods: + + 1. Bird + 2. McHale + 3. Parish + +It's important to note that the actual numbers you use to mark the +list have no effect on the HTML output Markdown produces. The HTML +Markdown produces from the above list is: + +
    +
  1. Bird
    2. +
  2. McHale
    3. +
  3. Parish
    4. +
+ +If you instead wrote the list in Markdown like this: + + 1. Bird + 1. McHale + 1. Parish + +or even: + + 3. Bird + 1. McHale + 8. Parish + +you'd get the exact same HTML output. The point is, if you want to, +you can use ordinal numbers in your ordered Markdown lists, so that +the numbers in your source match the numbers in your published HTML. +But if you want to be lazy, you don't have to. + +If you do use lazy list numbering, however, you should still start the +list with the number 1. At some point in the future, Markdown may support +starting ordered lists at an arbitrary number. + +List markers typically start at the left margin, but may be indented by +up to three spaces. List markers must be followed by one or more spaces +or a tab. + +To make lists look nice, you can wrap items with hanging indents: + + * Lorem ipsum dolor sit amet, consectetuer adipiscing elit. + Aliquam hendrerit mi posuere lectus. Vestibulum enim wisi, + viverra nec, fringilla in, laoreet vitae, risus. + * Donec sit amet nisl. Aliquam semper ipsum sit amet velit. + Suspendisse id sem consectetuer libero luctus adipiscing. + +But if you want to be lazy, you don't have to: + + * Lorem ipsum dolor sit amet, consectetuer adipiscing elit. + Aliquam hendrerit mi posuere lectus. Vestibulum enim wisi, + viverra nec, fringilla in, laoreet vitae, risus. + * Donec sit amet nisl. Aliquam semper ipsum sit amet velit. + Suspendisse id sem consectetuer libero luctus adipiscing. + +If list items are separated by blank lines, Markdown will wrap the +items in `

` tags in the HTML output. For example, this input: + + * Bird + * Magic + +will turn into: + +

    +
  • Bird
    • +
  • Magic
    • +
+ +But this: + + * Bird + + * Magic + +will turn into: + +
    +

  • Bird

    • +

  • Magic

    • +
+ +List items may consist of multiple paragraphs. Each subsequent +paragraph in a list item must be intended by either 4 spaces +or one tab: + + 1. This is a list item with two paragraphs. Lorem ipsum dolor + sit amet, consectetuer adipiscing elit. Aliquam hendrerit + mi posuere lectus. + + Vestibulum enim wisi, viverra nec, fringilla in, laoreet + vitae, risus. Donec sit amet nisl. Aliquam semper ipsum + sit amet velit. + + 2. Suspendisse id sem consectetuer libero luctus adipiscing. + +It looks nice if you indent every line of the subsequent +paragraphs, but here again, Markdown will allow you to be +lazy: + + * This is a list item with two paragraphs. + + This is the second paragraph in the list item. You're + only required to indent the first line. Lorem ipsum dolor + sit amet, consectetuer adipiscing elit. + + * Another item in the same list. + +To put a blockquote within a list item, the blockquote's `>` +delimiters need to be indented: + + * A list item with a blockquote: + + > This is a blockquote + > inside a list item. + +To put a code block within a list item, the code block needs +to be indented *twice* -- 8 spaces or two tabs: + + * A list item with a code block: + + + + +It's worth noting that it's possible to trigger an ordered list by +accident, by writing something like this: + + 1986. What a great season. + +In other words, a *number-period-space* sequence at the beginning of a +line. To avoid this, you can backslash-escape the period: + + 1986\. What a great season. + + + +

Code Blocks

+ +Pre-formatted code blocks are used for writing about programming or +markup source code. Rather than forming normal paragraphs, the lines +of a code block are interpreted literally. Markdown wraps a code block +in both `
` and `` tags.
+
+To produce a code block in Markdown, simply indent every line of the
+block by at least 4 spaces or 1 tab. For example, given this input:
+
+    This is a normal paragraph:
+
+        This is a code block.
+
+Markdown will generate:
+
+    
This is a normal paragraph:

+
+    
This is a code block.
+    

+
+One level of indentation -- 4 spaces or 1 tab -- is removed from each
+line of the code block. For example, this:
+
+    Here is an example of AppleScript:
+
+        tell application "Foo"
+            beep
+        end tell
+
+will turn into:
+
+    
Here is an example of AppleScript:

+
+    
tell application "Foo"
+        beep
+    end tell
+    

+
+A code block continues until it reaches a line that is not indented
+(or the end of the article).
+
+Within a code block, ampersands (`&`) and angle brackets (`<` and `>`)
+are automatically converted into HTML entities. This makes it very
+easy to include example HTML source code using Markdown -- just paste
+it and indent it, and Markdown will handle the hassle of encoding the
+ampersands and angle brackets. For example, this:
+
+        

+            © 2004 Foo Corporation
+        

+
+will turn into:
+
+    
<div class="footer">
+        &copy; 2004 Foo Corporation
+    </div>
+    

+
+Regular Markdown syntax is not processed within code blocks. E.g.,
+asterisks are just literal asterisks within a code block. This means
+it's also easy to use Markdown to write about Markdown's own syntax.
+
+
+
+
Horizontal Rules

+
+You can produce a horizontal rule tag (`
`) by placing three or
+more hyphens, asterisks, or underscores on a line by themselves. If you
+wish, you may use spaces between the hyphens or asterisks. Each of the
+following lines will produce a horizontal rule:
+
+    * * *
+
+    ***
+
+    *****
+
+    - - -
+
+    ---------------------------------------
+
+
+* * *
+
+
Span Elements

+
+
+
+Markdown supports two style of links: *inline* and *reference*.
+
+In both styles, the link text is delimited by [square brackets].
+
+To create an inline link, use a set of regular parentheses immediately
+after the link text's closing square bracket. Inside the parentheses,
+put the URL where you want the link to point, along with an *optional*
+title for the link, surrounded in quotes. For example:
+
+    This is [an example](http://example.com/ "Title") inline link.
+
+    [This link](http://example.net/) has no title attribute.
+
+Will produce:
+
+    
This is 
+    an example inline link.

+
+    
This link has no
+    title attribute.

+
+If you're referring to a local resource on the same server, you can
+use relative paths:
+
+    See my [About](/about/) page for details.   
+
+Reference-style links use a second set of square brackets, inside
+which you place a label of your choosing to identify the link:
+
+    This is [an example][id] reference-style link.
+
+You can optionally use a space to separate the sets of brackets:
+
+    This is [an example] [id] reference-style link.
+
+Then, anywhere in the document, you define your link label like this,
+on a line by itself:
+
+    [id]: http://example.com/  "Optional Title Here"
+
+That is:
+
+*   Square brackets containing the link identifier (optionally
+    indented from the left margin using up to three spaces);
+*   followed by a colon;
+*   followed by one or more spaces (or tabs);
+*   followed by the URL for the link;
+*   optionally followed by a title attribute for the link, enclosed
+    in double or single quotes, or enclosed in parentheses.
+
+The following three link definitions are equivalent:
+
+	[foo]: http://example.com/  "Optional Title Here"
+	[foo]: http://example.com/  'Optional Title Here'
+	[foo]: http://example.com/  (Optional Title Here)
+
+**Note:** There is a known bug in Markdown.pl 1.0.1 which prevents
+single quotes from being used to delimit link titles.
+
+The link URL may, optionally, be surrounded by angle brackets:
+
+    [id]:   "Optional Title Here"
+
+You can put the title attribute on the next line and use extra spaces
+or tabs for padding, which tends to look better with longer URLs:
+
+    [id]: http://example.com/longish/path/to/resource/here
+        "Optional Title Here"
+
+Link definitions are only used for creating links during Markdown
+processing, and are stripped from your document in the HTML output.
+
+Link definition names may constist of letters, numbers, spaces, and
+punctuation -- but they are *not* case sensitive. E.g. these two
+links:
+
+	[link text][a]
+	[link text][A]
+
+are equivalent.
+
+The *implicit link name* shortcut allows you to omit the name of the
+link, in which case the link text itself is used as the name.
+Just use an empty set of square brackets -- e.g., to link the word
+"Google" to the google.com web site, you could simply write:
+
+	[Google][]
+
+And then define the link:
+
+	[Google]: http://google.com/
+
+Because link names may contain spaces, this shortcut even works for
+multiple words in the link text:
+
+	Visit [Daring Fireball][] for more information.
+
+And then define the link:
+	
+	[Daring Fireball]: http://daringfireball.net/
+
+Link definitions can be placed anywhere in your Markdown document. I
+tend to put them immediately after each paragraph in which they're
+used, but if you want, you can put them all at the end of your
+document, sort of like footnotes.
+
+Here's an example of reference links in action:
+
+    I get 10 times more traffic from [Google] [1] than from
+    [Yahoo] [2] or [MSN] [3].
+
+      [1]: http://google.com/        "Google"
+      [2]: http://search.yahoo.com/  "Yahoo Search"
+      [3]: http://search.msn.com/    "MSN Search"
+
+Using the implicit link name shortcut, you could instead write:
+
+    I get 10 times more traffic from [Google][] than from
+    [Yahoo][] or [MSN][].
+
+      [google]: http://google.com/        "Google"
+      [yahoo]:  http://search.yahoo.com/  "Yahoo Search"
+      [msn]:    http://search.msn.com/    "MSN Search"
+
+Both of the above examples will produce the following HTML output:
+
+    
I get 10 times more traffic from Google than from
+    Yahoo
+    or MSN.

+
+For comparison, here is the same paragraph written using
+Markdown's inline link style:
+
+    I get 10 times more traffic from [Google](http://google.com/ "Google")
+    than from [Yahoo](http://search.yahoo.com/ "Yahoo Search") or
+    [MSN](http://search.msn.com/ "MSN Search").
+
+The point of reference-style links is not that they're easier to
+write. The point is that with reference-style links, your document
+source is vastly more readable. Compare the above examples: using
+reference-style links, the paragraph itself is only 81 characters
+long; with inline-style links, it's 176 characters; and as raw HTML,
+it's 234 characters. In the raw HTML, there's more markup than there
+is text.
+
+With Markdown's reference-style links, a source document much more
+closely resembles the final output, as rendered in a browser. By
+allowing you to move the markup-related metadata out of the paragraph,
+you can add links without interrupting the narrative flow of your
+prose.
+
+
+
Emphasis

+
+Markdown treats asterisks (`*`) and underscores (`_`) as indicators of
+emphasis. Text wrapped with one `*` or `_` will be wrapped with an
+HTML `` tag; double `*`'s or `_`'s will be wrapped with an HTML
+`` tag. E.g., this input:
+
+    *single asterisks*
+
+    _single underscores_
+
+    **double asterisks**
+
+    __double underscores__
+
+will produce:
+
+    single asterisks
+
+    single underscores
+
+    double asterisks
+
+    double underscores
+
+You can use whichever style you prefer; the lone restriction is that
+the same character must be used to open and close an emphasis span.
+
+Emphasis can be used in the middle of a word:
+
+    un*fucking*believable
+
+But if you surround an `*` or `_` with spaces, it'll be treated as a
+literal asterisk or underscore.
+
+To produce a literal asterisk or underscore at a position where it
+would otherwise be used as an emphasis delimiter, you can backslash
+escape it:
+
+    \*this text is surrounded by literal asterisks\*
+
+
+
+
Code

+
+To indicate a span of code, wrap it with backtick quotes (`` ` ``).
+Unlike a pre-formatted code block, a code span indicates code within a
+normal paragraph. For example:
+
+    Use the `printf()` function.
+
+will produce:
+
+    
Use the printf() function.

+
+To include a literal backtick character within a code span, you can use
+multiple backticks as the opening and closing delimiters:
+
+    ``There is a literal backtick (`) here.``
+
+which will produce this:
+
+    
There is a literal backtick (`) here.

+
+The backtick delimiters surrounding a code span may include spaces --
+one after the opening, one before the closing. This allows you to place
+literal backtick characters at the beginning or end of a code span:
+
+	A single backtick in a code span: `` ` ``
+	
+	A backtick-delimited string in a code span: `` `foo` ``
+
+will produce:
+
+	
A single backtick in a code span: `

+	
+	
A backtick-delimited string in a code span: `foo`

+
+With a code span, ampersands and angle brackets are encoded as HTML
+entities automatically, which makes it easy to include example HTML
+tags. Markdown will turn this:
+
+    Please don't use any `` tags.
+
+into:
+
+    
Please don't use any <blink> tags.

+
+You can write this:
+
+    `—` is the decimal-encoded equivalent of `—`.
+
+to produce:
+
+    
&#8212; is the decimal-encoded
+    equivalent of &mdash;.

+
+
+
+
Images

+
+Admittedly, it's fairly difficult to devise a "natural" syntax for
+placing images into a plain text document format.
+
+Markdown uses an image syntax that is intended to resemble the syntax
+for links, allowing for two styles: *inline* and *reference*.
+
+Inline image syntax looks like this:
+
+    ![Alt text](/path/to/img.jpg)
+
+    ![Alt text](/path/to/img.jpg "Optional title")
+
+That is:
+
+*   An exclamation mark: `!`;
+*   followed by a set of square brackets, containing the `alt`
+    attribute text for the image;
+*   followed by a set of parentheses, containing the URL or path to
+    the image, and an optional `title` attribute enclosed in double
+    or single quotes.
+
+Reference-style image syntax looks like this:
+
+    ![Alt text][id]
+
+Where "id" is the name of a defined image reference. Image references
+are defined using syntax identical to link references:
+
+    [id]: url/to/image  "Optional title attribute"
+
+As of this writing, Markdown has no syntax for specifying the
+dimensions of an image; if this is important to you, you can simply
+use regular HTML `` tags.
+
+
+* * *
+
+
+
Miscellaneous

+
+
+
+Markdown supports a shortcut style for creating "automatic" links for URLs and email addresses: simply surround the URL or email address with angle brackets. What this means is that if you want to show the actual text of a URL or email address, and also have it be a clickable link, you can do this:
+
+    
+    
+Markdown will turn this into:
+
+    http://example.com/
+
+Automatic links for email addresses work similarly, except that
+Markdown will also perform a bit of randomized decimal and hex
+entity-encoding to help obscure your address from address-harvesting
+spambots. For example, Markdown will turn this:
+
+    
+
+into something like this:
+
+    address@exa
+    mple.com
+
+which will render in a browser as a clickable link to "address@example.com".
+
+(This sort of entity-encoding trick will indeed fool many, if not
+most, address-harvesting bots, but it definitely won't fool all of
+them. It's better than nothing, but an address published in this way
+will probably eventually start receiving spam.)
+
+
+
+
Backslash Escapes

+
+Markdown allows you to use backslash escapes to generate literal
+characters which would otherwise have special meaning in Markdown's
+formatting syntax. For example, if you wanted to surround a word with
+literal asterisks (instead of an HTML `` tag), you can backslashes
+before the asterisks, like this:
+
+    \*literal asterisks\*
+
+Markdown provides backslash escapes for the following characters:
+
+    \   backslash
+    `   backtick
+    *   asterisk
+    _   underscore
+    {}  curly braces
+    []  square brackets
+    ()  parentheses
+    #   hash mark
+	+	plus sign
+	-	minus sign (hyphen)
+    .   dot
+    !   exclamation mark
+