// =================================================================
// ProGrammar Grammar Definition File
// -----------------------------------------------------------------
//  
//  Markup.GDL -  Defines a general syntax for parsing documents
//                that are marked-up by tags.  This grammar accepts 
//                any tag name, as long as the beginning and ending 
//                tags match.  Specific markup languages, such as
//                HTML, can extend and constrain this grammar.
//
//  This example is intended for demonstration purposes only.
//
//  (c) Copyright 1999, 2000 NorKen Technologies, Inc.
//  All rights reserved.
//
// ==================================================================

grammar Markup 
{
	text ::= { section };

	section ::= 
		  script
		| start_tag [{ section }] [end_tag] 
		| comment 
		| doctype
		| plain_text
		;
	
	plain_text  ::= *("<");	// parse everything up to the next tag
	
	comment ::= "") "-->";
	
	doctype ::= "" ;
	
	script ::= start_script
				*(end_script) end_script ;
				
	start_script ::= "<" "script" *(">") ">" ;
	end_script   ::= "<" "/" "script" ">" ;
	
	doctype_info ::= *(">");
	
	start_tag ::= 	"<"
			element_name 
			[{ tag_attr }] 	// optional tag attributes
			">"
			;

	element_name  ::= identifier;

	tag_attr ::= attr_name ["=" attr_value_string];

	attr_name ::= '[a-zA-Z0-9-]+' ;

	// There are three different ways to delimit an attribute 
	// value: with double-quotes, single quotes, or not delimited.
	
	attr_value_string ::= "\"" attr_value "\""
					  |   "\'" attr_value "\'"
					  |        attr_value 
					  ;

	// Regardless of how the attribute value is delimited, we 
	// are only interested in the "value itself".  The following 
	// production shows how a nonterminal symbol can be parsed 
	// in different ways, depending upon the context in which it 
	// occurs. For example, when attr_value occurs in 
	// double-quotes, the parser will scan all characters up to 
	// the closing quote; but when it occurs without quotations, 
	// the parser scans all characters up to the next whitespace 
	// or closing tag ('>') character.  Hence, symbol attr_value 
	// is "polymorphic".
			
	attr_value ::= 
		(? #VALUE == "\"") *("\"")     // scan to closing dbl-quote
		 | (? #VALUE == "\'") *("\'")  // scan to closing single-quote
		 | '[^\32\t\n\r>]+'            // scan to next whitespace or '>'
				; 
				
	end_tag ::= "";
			
	// The constraint "(? #VALUE = ^^section.start_tag.element_name)" 
	// enforces the rule that end_tags must have the same name as their 
	// corresponding start_tag.

	end_tag_name  ::= alphanumeric;
};


// =================================================================
// ProGrammar Grammar Definition File
// -----------------------------------------------------------------
//  
//  Html.GDL - Parses HTML documents; extends the "Markup" grammar.
//
//  This example is intended for demonstration purposes only.
//
//  (c) Copyright 1999, 2000 NorKen Technologies, Inc.
//  All rights reserved.
//
// ==================================================================


grammar HTML extends Markup	// extend the 'Markup' grammar 
{
	text ::= Markup.text;	// start symbol
	
	// Constrain the possible values for "element_name" to those 
	// defined in HTML 3.2

	element_name ::= 
		Markup.element_name
			(? #WARN = 100, 
			   #VALUE ::= html32_tag; )	; // constraint
	
	// define valid HTML tag names
	
	html32_tag ::= 
		( "A"         | "ADDRESS"     | "AREA"      | "B"
		| "BASE"      | "BASEFONT"    | "BGSOUND"   | "BIG"
		| "BLINK"     | "BLOCKQUOTE"  | "BODY"      | "BR"		
		| "CAPTION"   | "CENTER"      | "CITE"      | "CODE"    
		| "COL"
		| "COLGROUP"  | "COMMENT"     | "DFN"       | "DIR"
		| "DIV"       | "DL"          | "DT"        | "EM"      
		| "FONT"
		| "FORM"      | "FRAME"       | "FRAMESET"  | "HEAD"
		| "HR"        | "HTML"        | "I"         | "IMG"
		| "INPUT"     | "ISINDEX"     | "KBD"       | "LI"
		| "LINK"      | "LISTING"     | "MAP"       | "MARQUEE"	
		| "MENU"      | "META"        | "NEXTID"    | "NOBR"		
		| "NOFRAMES"  | "OL"          | "OPTION"    | "P"		
		| "PLAINTEXT" | "PRE"         | "SAMP"      | "SCRIPT"
		| "SELECT"    | "SMALL"       | "STRIKE"    | "STRONG"
		| "SUB"       | "SUP"         | "TABLE"     | "TBODY"
		| "TD"        | "TEXTAREA"    | "TFOOT"     | "TH"
		| "THEAD"     | "TITLE"       | "TR"        | "TT"
		| "U"         | "UL"          | "VAR"       | "WBR"
		| "XMP" 
		)
		"H" numeric<1>
		;
			
	grammar Attrs
	{
		a_attrs	::= 
			  "HREF" | "METHODS" | "NAME" | "REL" 
			| "REV" | "TARGET" | "TITLE" | "URN" ;
	
		area_attrs ::= 
			"SHAPE" | "COORDS" | "HREF" ;
	
		basefont_attrs ::= 
			"FACE" | "COLOR" ;
	
		bgsound_attrs ::= 
			"SRC" | "LOOP" ;
	
		body_attrs ::= 
			"BACKGROUND" | "BGCOLOR" | "BGPROPERTIES" 
			| "LEFTMARGIN" | "LINK" | "VLINK" | "ALINK" 
			| "TEXT" | "TOPMARGIN" | "STYLESRC" 
			| "MARGINWIDTH" | "MARGINHEIGHT" ;
			  
		base_attrs	::= "HREF" | "TARGET" ;
	
		caption_attrs ::= "ALIGN" | "VALIGN" ;
	
		col_attrs ::= "ALIGN" | "SPAN" ;
	
		colgroup_attrs ::= "ALIGN" | "SPAN" | "VALIGN" ;
	
		font_attrs ::= "COLOR" | "FACE" | "SIZE" ;
	
		form_attrs ::= "ACTION" | "ENCTYPE" | "METHOD" ;
	
		frame_attrs	::= 
			"SRC" | "NAME" | "MARGINWIDTH" | "MARGINHEIGHT" 
			| "SCROLLING" |   "NORESIZE" | "FRAMEBORDER" 
			| "FRAMESPACING" ;
				
		frameset_attrs	::= 
			"ROWS" | "COLS" | frame_attrs;				
	
		hr_attrs ::= 
			"ALIGN" | "COLOR" | "NOSHADE" | "SIZE" | "WIDTH" ;
	
		input_attrs	::= 
			"ALIGN" | "CHECKED" | "MAXLENGTH" | "NAME" | "SIZE" 
			| "SRC" | "TYPE" |   "BUTTON" | "CHECKBOX" | "FILE" 
			| "HIDDEN" | "IMAGE" | "PASSWORD" | "RADIO" 
			| "RESET" | "SUBMIT" | "TEXT" | "TEXTAREA" | "VALUE" ;
				
	
		img_attrs ::= 
			"ALIGN" | "ALT" | "BORDER" | "ISMAP" | "LOWSRC" 
			| "SRC"	|   "VSPACE" | "HSPACE" | "WIDTH" 
			| "HEIGHT" | "USEMAP"
			// MS Explorer
			|   "CONTROLS" | "DYNSRC" | "LOOP" | "LOOPDELAY" 
			| "START" | "VRML" | "NAME"	;

		isindex_attrs ::= 
			"ACTION" | "PROMPT" ;
	
		link_attrs ::= a_attrs;
	
		map_attrs ::= "NAME" ;
	
		marquee_attrs ::= 
			"ALIGN" | "BEHAVIOR" | "BGCOLOR" | "DIRECTION" 
			| "HEIGHT" | "HSPACE" | "LOOP" | "SCROLLAMOUNT" 
			| "SCROLLDELAY" | "VSPACE" | "WIDTH" ;
				
		meta_attrs	::= "CONTENT" | "HTTP-EQUIV" | "NAME" ;
	
		option_attrs ::= "SELECTED" | "VALUE" ;
	
		p_attrs	 ::= "ALIGN" ;
	
		pre_attrs ::= "WIDTH" ;
	
		select_attrs ::= "MULTIPLE" | "NAME" | "SIZE" ;
	
		table_attrs	::= 
			"ALIGN" | "BACKGROUND" | "BGCOLOR" | "BORDER" 
			| "BORDERCOLOR"	|   "BORDERCOLORDARK" 
			| "BORDERCOLORLIGHT" | "CELLPADDING" | "CELLSPACING" 
			| "FRAME" | "HEIGHT" | "RULES" | "VALIGN" | "WIDTH"
					;
				
		td_attrs ::= 
			"ALIGN" | "BACKGROUND" | "BGCOLOR" | "BORDERCOLOR" 
			| "BORDERCOLORDARK"	|   "BORDERCOLORLIGHT" | "COLSPAN" 
			| "HEIGHT" | "NOWRAP" | "ROWSPAN" |   "VALIGN" 
			| "WIDTH"
					;
	
		textarea_attrs ::= "WRAP" ;
	
		th_attrs ::= td_attrs ;
	
		tr_attrs ::= 
			"ALIGN" | "BGCOLOR" | "BORDERCOLOR" 
			| "BORDERCOLORDARK" | "BORDERCOLORLIGHT" | "VALIGN"
					;

		// Constraints on attr_values
		// append "_value" to attribute name and the production 
		// will be called automatically by the constraint.
	
		align_value ::= 
			"CENTER" | "JUSTIFY" | "LEFT" 
			| "RIGHT" | "TOP" | "BOTTOM" ;
		
		height_value ::= value_or_percent;

		size_value ::= ["-"|"+"] numeric;

		valign_value ::= "TOP" | "BOTTOM";
		
		value_or_percent ::= numeric ["%"];

		width_value  ::= value_or_percent;
	};

	attr_name ::= Markup.attr_name
		(? 	#WARN = 101,
			#VALUE ::= 
				^#ISSYMBOL("Attrs." + 
					^*start_tag.element_name + "_attrs") *()
				  | #SYMBOL("Attrs." + 
					^*start_tag.element_name + "_attrs");
		);
			
	attr_value ::= Markup.attr_value 
		(? 	#WARN = 102,
			#VALUE ::= 
				^#ISSYMBOL("Attrs." + ^.attr_name + "_value") *()
				| #SYMBOL("Attrs." + ^.attr_name + "_value") ;
		);
};