Markup spec/ANTLR/Images

The following code does a pretty good job of handling images. Obviously all the actual inline text processing and definitions of text are primitive.

Notes:

• It can handle nested images
• It can handle links in captions, which don't trouble it at all: [[image:foo.jpg|[[somelink]]]]
• It recognises all the defined options. Unfortunately it's not quite as flexible as the currentparser in allowing ad hoc definitions like "thumb=$" etc.
• Its treatment of options is basically, if the text doesn't match *exactly* a specified format (eg, "...|thumb=xxx|", then it's a caption. The following are teated as captions:
  • ...| <anything>
  • ...|thumb |... (possibly too harsh...)
  • ...|thumb =...|
  • ...|thumbn|...
• It's case insensitive for all "magic word" matches, case sensitive otherwise.

Test cases

These test cases are parsed correctly:

[[image:foo.jpeg|capp|thumbnail|thumbnail=foo.jpg|mythumbnailishot my thumbnail is great|So is this [[image:inline.png|Inline image...]] (not a gif).]]

[[Image:Lung small cell carcinoma (1) by core needle biopsy.jpg|thumb|left|Small cell lung carcinoma (microscopic view of a core needle biopsy)]]

[[Image:Smith_gun_and_limber.JPG|thumb|300px|Smith Gun and limber at [[Fort Nelson, Portsmouth|The Royal Armouries, Fort Nelson]].]]

[[Image:Slovakiatynka.svg|40px]]

[[Image:Saltbox_side_elevation.png|thumb|End elevation of a saltbox house, illustrating the distinctive roof line.]] 

[[Image: Riven Oak Clapboards.jpg|thumb|1683 Riven Oak Clapboards [[Ephraim Hawley House]], [[Trumbull, Connecticut|Trumbull]], [[Fairfield County]], [[Connecticut]].]]

[[Image:Bothferry.jpg|left|thumb|200px| Boothferry Park]]

grammar image4;
@header {
}
/*
[[image:foo.jpeg|capp|thumbnail|thumbnail=foo.jpg|mythumbnailishot my thumbnail is great|So is this [[image:inline.png|Inline image...]] (not a gif).]]
*/

@members {
  String _mw_image_namespace = "image";
  
  // This little inline function is crucial, allowing us to match the text of some token
  // with an expected piece of text. It would be easy to adapt it to fetching the actual magic words
  // from an external library, text file etc.
  boolean textis(String mw) {  
    return input.LT(1).getText().equalsIgnoreCase(mw);
  }
}
start	:	(imageinline ws N*)/* * */;
imageinline: LINK_START image_namespace COLON ws imagename ( PIPE optionorcaption )* LINK_END ;
linkinline
	:	LINK_START (.*) LINK_END; /* very abbreviated ...*/

 imagename: pagename ws DOT ws imageextension;

/* Future passes/actions etc can readily retrieve the extension text, so just validate for now? */
 imageextension: 
 	{textis("jpeg")
 	| textis("jpg")
 	| textis("png")
 	| textis("svg")
 	| textis("gif")
 	| textis("bmp")}? letters;


 optionorcaption
 	:	(imagemodeautothumb (PIPE | LINK_END)) => imagemodeautothumb /* move it up here as it's so common */
 	|	(SPACE) => caption
 	|	(imageoption (PIPE | LINK_END)) => imageoption
 	| 	caption;
imageoption: 	
	 imagemodemanualthumb 
	| imagemodeautothumb 
	| imagemodeframe 
	| imagemodeframeless
	//| imagemodepage /* something weird about this one but I don't know what. */
	| imagemodeupright
	| imagemodeborder
	| imagesizeparameter
	| imagealignleft
	| imagealigncenter
	| imagealignright
	| imagealignnone
	| imagevalignbaseline
	| imagevalignsub
	| imagevalignsuper
	| imagevaligntop
	| imagevaligntexttop
	| imagevalignmiddle
	| imagevalignbottom
	| imagevaligntextbottom;

imagemodemanualthumb: 	mw_img_manualthumb;
imagemodeautothumb: 	mw_img_thumbnail;
imagemodeframe: 	mw_img_frame;
imagemodeframeless:	mw_img_frameless;
imagemodepage:	 	mw_img_page;
imagemodeupright:       mw_img_upright;
imagemodeborder:        mw_img_border;
imagesizeparameter: 	POSITIVE_INT mw_img_width; 	
imagealignleft: 	mw_img_left ;
imagealigncenter: 	mw_img_center ;
imagealignright: 	mw_img_right ;
imagealignnone: 	mw_img_none;
imagevalignbaseline: 	mw_img_baseline ;
imagevalignsub: 	mw_img_sub;
imagevalignsuper: 	mw_img_super;
imagevaligntop: 	mw_img_top;
imagevaligntexttop: 	mw_img_text_top;
imagevalignmiddle: 	mw_img_middle;
imagevalignbottom: 	mw_img_bottom;
imagevaligntextbottom: 	mw_img_text_bottom;

/* default settings: */
/* Hmm, user-definable grammar seems to be a bad idea. Assume that the img_manualthumb is always something followed by the name. */
 mw_img_manualthumb	: {textis("thumbnail") | textis("thumb")}? mwletters EQUALS imagename; // don't forget thumb=
 mw_img_thumbnail	: {textis("thumbnail") | textis("thumb")}? mwletters; //'thumbnail' | 'thumb';
 mw_img_frame		: {textis("framed") | textis("enframed") | textis("frame")}? mwletters; 
 mw_img_frameless	: {textis("frameless")}? mwletters;
 mw_img_page		: {textis("page")}? mwletters (SPACE | EQUALS) mwletters; //'page=$1' | 'page $1' ; /*??? (where is this used?);*/
 mw_img_upright		: {textis("upright")}? mwletters EQUALS? POSITIVE_INT?; //'upright' (  '='? POSITIVE_INT)?;
 mw_img_border		: {textis("border")}? mwletters;
 mw_img_width		: {textis("px")}? mwletters;

 mw_img_baseline	: {textis("baseline")}? mwletters;
 mw_img_sub		: {textis("sub")}? mwletters;
 mw_img_super		: {textis("super") | textis("sup")}? mwletters;
 mw_img_top		: {textis("top")}? mwletters;
 mw_img_text_top	: {textis("text-top")}? mwletters;
 mw_img_middle		: {textis("middle")}? mwletters;
 mw_img_bottom		: {textis("bottom")}? mwletters;
 mw_img_text_bottom	: {textis("text-bottom")}? mwletters;

mw_img_left		: {textis("left")}? letters;
mw_img_center		: {textis("center") | textis("centre")}? letters;
mw_img_right		: {textis("right")}? letters;
mw_img_none		: {textis("none")}? letters;

image_namespace	: {textis(_mw_image_namespace)}? mwletters;

 
LINK_START: '[[';
LINK_END: ']]';

COLON	:	':';
PIPE	:	'|';

caption: inline_text;
pagename: (letters | POSITIVE_INT) (letters | POSITIVE_INT | DOT | SPACE | UNDERSCORE | HYPHEN | OPEN_PAREN | CLOSE_PAREN) *;

inline_text:		/*letters*/ (letters | SPACE | DOT |POSITIVE_INT|COMMA|imageinline|linkinline|OPEN_PAREN | CLOSE_PAREN)*;

POSITIVE_INT:	'0'..'9'+;


DOT		:	'.';
SPACE   	:	' ';	
EQUALS		:	'=';
UNDERSCORE	:	'_';
HYPHEN          :       '-';
COMMA		:	',';
OPEN_PAREN	:	'(';
CLOSE_PAREN     :	')';

LETTERS	:	LETTER+;
fragment
LETTER	:	('A'..'Z'|'a'..'z');
letters	:	LETTERS;	

mwletters:	LETTERS (LETTERS | HYPHEN | UNDERSCORE | POSITIVE_INT)*;  

N	:	'\r'? '\n';
ws	:	SPACE*;