GrammarWML - Revision history

Bssarkar: /* Help Markup */ typofix: XMl -> XML

2026-04-25T13:12:13Z

Help Markup: typofix: XMl -> XML

← Older revision		Revision as of 13:12, 25 April 2026
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	== Help Markup ==		== Help Markup ==

	This grammar defines the [[help markup]] used in Wesnoth help topics and GUI2 rich labels. It's ''almost'' HTML and ''almost'' ~~XMl~~ but not quite either.		This grammar defines the [[help markup]] used in Wesnoth help topics and GUI2 rich labels. It's ''almost'' HTML and ''almost'' XML but not quite either.

	<syntaxhighlight lang=ebnf>		<syntaxhighlight lang=ebnf>

Celtic Minstrel: /* Progressive Values */ Add new section covering AnimationWML's progressive values

2026-03-19T07:45:09Z

Progressive Values: Add new section covering AnimationWML's progressive values

@@ Line 180: / Line 180: @@
 name = name_char , {name_char} ;
 name_char = ?letter? | ?digit? | '_'
 </syntaxhighlight>
 [[Category:WML Reference]]

Celtic Minstrel: Simplify a few very basic productions with special symbols

2026-03-19T07:26:04Z

Simplify a few very basic productions with special symbols

← Older revision		Revision as of 07:26, 19 March 2026
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	** <tt>?newline?</tt>, <tt>?tab?</tt>, and <tt>?space?</tt> represent the named non-printable characters.		** <tt>?newline?</tt>, <tt>?tab?</tt>, and <tt>?space?</tt> represent the named non-printable characters.
	** <tt>?unicode?</tt> represents any valid Unicode character.		** <tt>?unicode?</tt> represents any valid Unicode character.
			** <tt>?digit?</tt> represents any decimal digit.
			** <tt>?hexdigit?</tt> represents any hexadecimal digit.
			** <tt>?letter?</tt> represents any ASCII Latin letter in either uppercase or lowercase.

	== WML Preprocessor ==		== WML Preprocessor ==
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	comparison_op = '<' \| '<=' \| '==' \| '!=' \| '>=' \| '>' ;		comparison_op = '<' \| '<=' \| '==' \| '!=' \| '>=' \| '>' ;
	version_string = integer , ['.' , integer] ;		version_string = integer , ['.' , integer] ;
	integer = digit , {digit} ;		integer = ?digit? , {?digit?} ;
	~~digit = '0' \| '1' \| '2' \| '3' \| '4' \| '5' \| '6' \| '7' \| '8' \| '9'~~ ;
	</syntaxhighlight>		</syntaxhighlight>

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	raw_string = '<<' , {?unicode? - '>' \| '>' , ?unicode? - '>'} , '>>' ;		raw_string = '<<' , {?unicode? - '>' \| '>' , ?unicode? - '>'} , '>>' ;
	textdomain = '#textdomain' domain_char , {domain_char} , ?newline? ;		textdomain = '#textdomain' domain_char , {domain_char} , ?newline? ;
	wml_id_char = ~~lowercase \| uppercase~~ \| digit \| '_~~' ;~~		wml_id_char = ?letter? \| ?digit? \| '_' ;
	~~lowercase = 'a' \| 'b' \| 'c' \| 'd' \| 'e' \| 'f' \| 'g' \| 'h' \| 'i' \| 'j' \| 'k' \| 'l' \| 'm'~~
	~~\| 'n' \| 'o' \| 'p' \| 'q' \| 'r' \| 's' \| 't' \| 'u' \| 'v' \| 'w' \| 'x' \| 'y' \| 'z' ;~~
	~~uppercase = 'A' \| 'B' \| 'C' \| 'D' \| 'E' \| 'F' \| 'G' \| 'H' \| 'I' \| 'J' \| 'K' \| 'L' \| 'M'~~
	~~\| 'N' \| 'O' \| 'P' \| 'Q' \| 'R' \| 'S' \| 'T' \| 'U' \| 'V' \| 'W' \| 'X' \| 'Y' \| 'Z' ;~~
	~~digit = '0' \| '1' \| '2' \| '3' \| '4' \| '5' \| '6' \| '7' \| '8' \| '9~~' ;
	domain_char = wml_id_char \| '-' ;		domain_char = wml_id_char \| '-' ;
	</syntaxhighlight>		</syntaxhighlight>
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	wml_var_path = {wml_var_name , [wml_var_index] , '.'} , wml_var_name ;		wml_var_path = {wml_var_name , [wml_var_index] , '.'} , wml_var_name ;
	wml_var_name = wml_id_char, {wml_id_char} ; (* wml_id_char is defined in the WML grammar, above *)		wml_var_name = wml_id_char, {wml_id_char} ; (* wml_id_char is defined in the WML grammar, above *)
	wml_var_index = '[' , digit , {digit} , ']' ; ~~(* as is digit *)~~		wml_var_index = '[' , ?digit? , {?digit?} , ']' ;
	wml_var_default = '?' , default_char, {default_char} , '\|' ;		wml_var_default = '?' , default_char, {default_char} , '\|' ;
	default_char = ?unicode? - '\|' ;		default_char = ?unicode? - '\|' ;
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	production = symbol , '=' , alternative , {'\|' , alternative} , ?newline? ;		production = symbol , '=' , alternative , {'\|' , alternative} , ?newline? ;
	symbol = symbol_char , {symbol_char} ;		symbol = symbol_char , {symbol_char} ;
	symbol_char = ~~lowercase \| uppercase~~ \| digit \| '_' ; (* Unsure on this, need to check it *)		symbol_char = ?letter? \| ?digit? \| '_' ; (* Unsure on this, need to check it *)
	alternative = {terminal} ;		alternative = {terminal} ;
	terminal = '{' , symbol , '}' \| '{!}' \| '{(}' \| '{)}' \| (?unicode? - '}') ;		terminal = '{' , symbol , '}' \| '{!}' \| '{(}' \| '{)}' \| (?unicode? - '}') ;
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	wfl_value = 'functions' \| wfl_name \| wfl_number \| wfl_string \| wfl_container \| wfl_function_call ;		wfl_value = 'functions' \| wfl_name \| wfl_number \| wfl_string \| wfl_container \| wfl_function_call ;
	wfl_name = wfl_id_char , {wfl_id_char} ;		wfl_name = wfl_id_char , {wfl_id_char} ;
	wfl_id_char = ~~lowercase \| uppercase~~ \| '_' ; (* Note: digits are NOT allowed! *)		wfl_id_char = ?letter? \| '_' ; (* Note: digits are NOT allowed! *)
	wfl_number = digit , {digit} , ['.' , digit , {digit}] ;		wfl_number = ?digit? , {?digit?} , ['.' , ?digit? , {?digit?}] ;
	wfl_string = "'" , {wfl_string_char \| wfl_string_subst \| wfl_string_escape} , "'" ;		wfl_string = "'" , {wfl_string_char \| wfl_string_subst \| wfl_string_escape} , "'" ;
	wfl_string_char = ?unicode? - ("'" \| "[") ;		wfl_string_char = ?unicode? - ("'" \| "[") ;
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	literal = ?unicode? - ('<' , '&' , '\') ;		literal = ?unicode? - ('<' , '&' , '\') ;
	escape = '\' , ?unicode? ;		escape = '\' , ?unicode? ;
	entity = '&#' , digit , {digit} , ';'		entity = '&#' , ?digit? , {?digit?} , ';'
	\| '&#x' , hexdigit , {hexdigit} , ';'		\| '&#x' , ?hexdigit? , {?hexdigit?} , ';'
	\| '&' , name , ';'		\| '&' , name , ';'
	;		;
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	;		;
	name = name_char , {name_char} ;		name = name_char , {name_char} ;
	~~digit = '0' \| '1' \| '2' \| '3' \| '4' \| '5' \| '6' \| '7' \| '8' \| '9' ;~~		name_char = ?letter? \| ?digit? \| '_'
	~~hexdigit = digit \| 'a' \| 'A' \| 'b' \| 'B' \| 'c' \| 'C' \| 'd' \| 'D' \| 'e' \| 'E' \| 'f' \| 'F' ;~~
	name_char = ~~lower \| upper~~ \| digit \| '_'
	</syntaxhighlight>		</syntaxhighlight>

	[[Category:WML Reference]]		[[Category:WML Reference]]

Celtic Minstrel: Summarize EBNF syntax at the top of the page, including the special extended syntax I'm using.

2026-03-19T07:19:56Z

Summarize EBNF syntax at the top of the page, including the special extended syntax I'm using.

← Older revision		Revision as of 07:19, 19 March 2026
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	{{WML Tags}}		{{WML Tags}}
	This page contains a formal grammar of the Wesnoth domain-specific languages, including WML and its preprocessor. It does not attempt to capture any of the ways that the Wesnoth engine may interpret a string, such as WML variable substitution. It also doesn't fully capture the potential consequences of macros, for example the use of unbalanced WML tags. The syntax used is [https://en.wikipedia.org/wiki/Extended_Backus%E2%80%93Naur_form Extended Backus-Naur form].		This page contains a formal grammar of the Wesnoth domain-specific languages, including WML and its preprocessor. It does not attempt to capture any of the ways that the Wesnoth engine may interpret a string, such as WML variable substitution. It also doesn't fully capture the potential consequences of macros, for example the use of unbalanced WML tags. The syntax used is [https://en.wikipedia.org/wiki/Extended_Backus%E2%80%93Naur_form Extended Backus-Naur form]:

			* Every rule is of the form <tt>nonterminal = rule ;</tt> with a terminating semicolon.
			* Comments are enclosed in <tt>(* these *)</tt>.
			* Literal values are enclosed in either double or single quotes. There is no special syntax inside quotes.
			* <tt>(...)</tt> can be used for grouping.
			* <tt>N * A</tt> where N is a number means "exactly N instances of A".
			* <tt>[A]</tt> means "zero or one instances of A".
			* <tt>{A}</tt> means "zero or more instances of A".
			* <tt>A , B</tt> means "A followed by B".
			* <tt>A \| B</tt> means "either A or B".
			* <tt>A - B</tt> means "A but not B".]
			* Some special values are enclosed in <tt>?...?</tt>. This document uses the following special values:
			** <tt>?newline?</tt>, <tt>?tab?</tt>, and <tt>?space?</tt> represent the named non-printable characters.
			** <tt>?unicode?</tt> represents any valid Unicode character.

	== WML Preprocessor ==		== WML Preprocessor ==
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	integer = digit , {digit} ;		integer = digit , {digit} ;
	digit = '0' \| '1' \| '2' \| '3' \| '4' \| '5' \| '6' \| '7' \| '8' \| '9' ;		digit = '0' \| '1' \| '2' \| '3' \| '4' \| '5' \| '6' \| '7' \| '8' \| '9' ;
	~~char = ?any unicode character? ;~~
	</syntaxhighlight>		</syntaxhighlight>

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	wml_value = wml_value_component , {'+' , [?newline? , [textdomain]] , wml_value_component} ;		wml_value = wml_value_component , {'+' , [?newline? , [textdomain]] , wml_value_component} ;
	wml_value_component = text \| ['_'] , (string \| raw_string) ;		wml_value_component = text \| ['_'] , (string \| raw_string) ;
	text = {~~char~~ - '+' \| '"' \| ?newline?} ;		text = {?unicode? - '+' \| '"' \| ?newline?} ;
	string = '"' . {~~char~~ - '"' \| '""'} , '"' ;		string = '"' . {?unicode? - '"' \| '""'} , '"' ;
	raw_string = '<<' , {~~char~~ - '>' \| '>' , ~~char~~ - '>'} , '>>' ;		raw_string = '<<' , {?unicode? - '>' \| '>' , ?unicode? - '>'} , '>>' ;
	textdomain = '#textdomain' domain_char , {domain_char} , ?newline? ;		textdomain = '#textdomain' domain_char , {domain_char} , ?newline? ;
	wml_id_char = lowercase \| uppercase \| digit \| '_' ;		wml_id_char = lowercase \| uppercase \| digit \| '_' ;
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	digit = '0' \| '1' \| '2' \| '3' \| '4' \| '5' \| '6' \| '7' \| '8' \| '9' ;		digit = '0' \| '1' \| '2' \| '3' \| '4' \| '5' \| '6' \| '7' \| '8' \| '9' ;
	domain_char = wml_id_char \| '-' ;		domain_char = wml_id_char \| '-' ;
	~~char = ?any unicode character? ;~~
	</syntaxhighlight>		</syntaxhighlight>

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	wml_var_index = '[' , digit , {digit} , ']' ; (* as is digit *)		wml_var_index = '[' , digit , {digit} , ']' ; (* as is digit *)
	wml_var_default = '?' , default_char, {default_char} , '\|' ;		wml_var_default = '?' , default_char, {default_char} , '\|' ;
	default_char = ~~char~~ - '\|' ;		default_char = ?unicode? - '\|' ;
	wml_formula = '$' , '(' , wfl_document , ')' ;		wml_formula = '$' , '(' , wfl_document , ')' ;
	</syntaxhighlight>		</syntaxhighlight>
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	symbol_char = lowercase \| uppercase \| digit \| '_' ; (* Unsure on this, need to check it *)		symbol_char = lowercase \| uppercase \| digit \| '_' ; (* Unsure on this, need to check it *)
	alternative = {terminal} ;		alternative = {terminal} ;
	terminal = '{' , symbol , '}' \| '{!}' \| '{(}' \| '{)}' \| (?~~any~~ unicode ~~character~~? - '}') ;		terminal = '{' , symbol , '}' \| '{!}' \| '{(}' \| '{)}' \| (?unicode? - '}') ;
	</syntaxhighlight>		</syntaxhighlight>

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	<syntaxhighlight lang=ebnf>		<syntaxhighlight lang=ebnf>
	wfl_comment = '#' , {wfl_comment_char} , '#' ;		wfl_comment = '#' , {wfl_comment_char} , '#' ;
	wfl_comment_char = ~~char~~ - '#' ;		wfl_comment_char = ?unicode? - '#' ;
	wfl_file_run = 'wfl' , wfl_string , wfl_file_content , 'wflend' ;		wfl_file_run = 'wfl' , wfl_string , wfl_file_content , 'wflend' ;
	wfl_file_content = {?any token? - 'wflend'} ;		wfl_file_content = {?any token? - 'wflend'} ;
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	wfl_number = digit , {digit} , ['.' , digit , {digit}] ;		wfl_number = digit , {digit} , ['.' , digit , {digit}] ;
	wfl_string = "'" , {wfl_string_char \| wfl_string_subst \| wfl_string_escape} , "'" ;		wfl_string = "'" , {wfl_string_char \| wfl_string_subst \| wfl_string_escape} , "'" ;
	wfl_string_char = ~~char~~ - ("'" \| "[") ;		wfl_string_char = ?unicode? - ("'" \| "[") ;
	wfl_string_subst = '[' , wfl_formula , ']' ;		wfl_string_subst = '[' , wfl_formula , ']' ;
	wfl_string_escape = "[']" \| '[(]' \| '[)]' ;		wfl_string_escape = "[']" \| '[(]' \| '[)]' ;
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	document = {text \| tag} ;		document = {text \| tag} ;
	text = {literal \| entity \| escape} ;		text = {literal \| entity \| escape} ;
	literal = ?~~any~~ unicode ~~character~~? - ('<' , '&' , '\') ;		literal = ?unicode? - ('<' , '&' , '\') ;
	escape = '\' , ?~~any~~ unicode ~~character~~? ;		escape = '\' , ?unicode? ;
	entity = '&#' , digit , {digit} , ';'		entity = '&#' , digit , {digit} , ';'
	\| '&#x' , hexdigit , {hexdigit} , ';'		\| '&#x' , hexdigit , {hexdigit} , ';'
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	;		;
	attribute = name , ['=' , attribute_value] ;		attribute = name , ['=' , attribute_value] ;
	attribute_value = {?~~any~~ unicode ~~character~~? - ("'" \| '"' \| ?space?)} (* Unquoted value *)		attribute_value = {?unicode? - ("'" \| '"' \| ?space?)} (* Unquoted value *)
	\| "'" , text - "'" , "'"		\| "'" , text - "'" , "'"
	\| '"' , text - '"' , '"'		\| '"' , text - '"' , '"'

Celtic Minstrel: /* Help Markup */ Add a new section describing Help markup

2026-03-19T07:11:29Z

Help Markup: Add a new section describing Help markup

@@ Line 145: / Line 145: @@
 wml_key_value = wfl_formula , '->' , wfl_formula ;
 wfl_function_call = wfl_name , '(' , [wfl_expression_list] , ')' ;
 </syntaxhighlight>
 [[Category:WML Reference]]

Celtic Minstrel: /* Context-free Grammars */ Add new section covering Context-free grammar

2026-03-19T06:57:33Z

Context-free Grammars: Add new section covering Context-free grammar

@@ Line 85: / Line 85: @@
 default_char = char - '|' ;
 wml_formula = '$' , '(' , wfl_document , ')' ;
 </syntaxhighlight>

Celtic Minstrel: Remove "Under Construction" note

2026-03-19T06:38:12Z

Remove "Under Construction" note

← Older revision		Revision as of 06:38, 19 March 2026
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	~~----~~

	~~'''Note:''' This page is currently undergoing reconstruction. Information on the page may become misleading or occasionally wrong for brief periods of time.~~

	~~----~~

	{{WML Tags}}		{{WML Tags}}
	This page contains a formal grammar of the Wesnoth domain-specific languages, including WML and its preprocessor. It does not attempt to capture any of the ways that the Wesnoth engine may interpret a string, such as WML variable substitution. It also doesn't fully capture the potential consequences of macros, for example the use of unbalanced WML tags. The syntax used is [https://en.wikipedia.org/wiki/Extended_Backus%E2%80%93Naur_form Extended Backus-Naur form].		This page contains a formal grammar of the Wesnoth domain-specific languages, including WML and its preprocessor. It does not attempt to capture any of the ways that the Wesnoth engine may interpret a string, such as WML variable substitution. It also doesn't fully capture the potential consequences of macros, for example the use of unbalanced WML tags. The syntax used is [https://en.wikipedia.org/wiki/Extended_Backus%E2%80%93Naur_form Extended Backus-Naur form].

Celtic Minstrel: /* Wesnoth Formula Language */ Rewrite in EBNF

2026-03-19T06:37:52Z

Wesnoth Formula Language: Rewrite in EBNF

← Older revision		Revision as of 06:37, 19 March 2026
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	This grammar describes the syntax of the [[Wesnoth Formula Language]]. Though it specifies the format of comments and file markers, they are not integrated into the main grammar since it treats the equivalently to whitespace. The grammar may not be completely accurate to the actual in-game parser.		This grammar describes the syntax of the [[Wesnoth Formula Language]]. Though it specifies the format of comments and file markers, they are not integrated into the main grammar since it treats the equivalently to whitespace. The grammar may not be completely accurate to the actual in-game parser.

	wfl_comment := '#' [^#]* '#'		<syntaxhighlight lang=ebnf>
	wfl_file_run := 'wfl' wfl_string «any token»* 'wflend'		wfl_comment = '#' , {wfl_comment_char} , '#' ;
	wfl_document := wfl_function_definition* wfl_formula		wfl_comment_char = char - '#' ;
	wfl_function_definition := 'def' wfl_name '(' wfl_function_args ')' wfl_formula ';'		wfl_file_run = 'wfl' , wfl_string , wfl_file_content , 'wflend' ;
	wfl_function_args := (wfl_function_arg (',' wfl_function_arg~~)*)?~~		wfl_file_content = {?any token? - 'wflend'} ;
	wfl_function_arg := wfl_name '*'?		wfl_document = {wfl_function_definition} , wfl_formula ;
	wfl_formula := 'not'? where_expression		wfl_function_definition = 'def' , wfl_name , '(' , [wfl_function_args] , ')' , wfl_formula , ';' ;
	~~wfl_formula :=~~ bracketed_expression		wfl_function_args = wfl_function_arg , {',' , wfl_function_arg} ;
	bracketed_expression := '(' wfl_formula ')'		wfl_function_arg = wfl_name , ['*'] ;
	where_expression := (boolean_or_expression \| bracketed_expression) ('where' wfl_variables)*		wfl_formula = ['not'] , where_expression \| bracketed_expression ;
	wfl_variables := wfl_variable (',' wfl_variable)*		bracketed_expression = '(' , wfl_formula , ')' ;
	wfl_variable := wfl_name '=' wfl_formula		where_expression = (boolean_or_expression \| bracketed_expression) , {'where' , wfl_variables} ;
	boolean_or_expression := (boolean_and_expression \| bracketed_expression) ('or' wfl_formula)*		wfl_variables = wfl_variable , {',' , wfl_variable} ;
	boolean_and_expression := (comparison_expression \| bracketed_expression) ('and' wfl_formula)*		wfl_variable = wfl_name , '=' , wfl_formula ;
	comparison_expression := (containment_expression \| bracketed_expression) (comparison_op wfl_formula)*		boolean_or_expression = (boolean_and_expression \| bracketed_expression) , {'or' , wfl_formula} ;
	comparison_op := '=' \| '!=' \| '<' \| '>' \| '<=' \| '>='		boolean_and_expression = (comparison_expression \| bracketed_expression) , {'and' , wfl_formula} ;
	containment_expression := (range_expression \| bracketed_expression) ('in' wfl_formula)*		comparison_expression = (containment_expression \| bracketed_expression) , {comparison_op , wfl_formula} ;
	range_expression := (additive_expression \| bracketed_expression) ('~' wfl_formula)*		comparison_op = '=' \| '!=' \| '<' \| '>' \| '<=' \| '>=' ;
	additive_expression := ~~negation_opt?~~ (multiplicative_expression \| bracketed_expression) (additive_op wfl_formula)*		containment_expression = (range_expression \| bracketed_expression) , {'in' , wfl_formula} ;
	negation_op := '-' \| '+'		range_expression = (additive_expression \| bracketed_expression) , {'~' , wfl_formula} ;
	additive_op := '-' \| '+' \| '..'		additive_expression = [negation_op] , (multiplicative_expression \| bracketed_expression) , {additive_op , wfl_formula} ;
	multiplicative_expression := (exponent_expression \| bracketed_expression) (multiplicative_op wfl_formula)*		negation_op = '-' \| '+' ;
	muliplicative_op := '*' \| '/' \| '%'		additive_op = '-' \| '+' \| '..' ;
	exponent_expression := (wfl_formula '^')* (dice_expression \| bracketed_expression)		multiplicative_expression := (exponent_expression \| bracketed_expression) , {multiplicative_op , wfl_formula} ;
	dice_expression := (dot_expression \| bracketed_expression) ('d' wfl_formula)*		muliplicative_op = '*' \| '/' \| '%' ;
	dot_expression := (wfl_value \| bracketed_expression) ('.' wfl_formula)*		exponent_expression = {wfl_formula , '^'} , (dice_expression \| bracketed_expression) ;
	wfl_value := 'functions' \| wfl_name \| wfl_number \| wfl_string \| wfl_container \| wfl_function_call		dice_expression = (dot_expression \| bracketed_expression) , {'d' , wfl_formula} ;
	wfl_name :~~= [a-zA-Z_]+~~		dot_expression = (wfl_value \| bracketed_expression) , {'.' , wfl_formula} ;
	wfl_number := [~~0-9]+ (~~'.' ~~[0-9~~]~~+)?~~		wfl_value = 'functions' \| wfl_name \| wfl_number \| wfl_string \| wfl_container \| wfl_function_call ;
	wfl_string := "'" ~~([^'[]+~~ \| wfl_string_subst \| wfl_string_escape)* "'"		wfl_name = wfl_id_char , {wfl_id_char} ;
	wfl_string_subst := '[' wfl_formula ']'		wfl_id_char = lowercase \| uppercase \| '_' ; (* Note: digits are NOT allowed! *)
	wfl_string_escape := "[']" \| '[(]' \| '[)]'		wfl_number = digit , {digit} , ['.' , digit , {digit}] ;
	wfl_container := '[' ('->' \| wfl_expression_list \| wfl_key_value_list)? ']'		wfl_string = "'" , {wfl_string_char \| wfl_string_subst \| wfl_string_escape} , "'" ;
	wfl_expression_list := wfl_formula (',' wfl_formula)*		wfl_string_char = char - ("'" \| "[") ;
	wfl_key_value_list := ~~wfl_formula~~ '->' wfl_formula (',~~' wfl_formula~~ '->' wfl_formula)*		wfl_string_subst = '[' , wfl_formula , ']' ;
	wfl_function_call := wfl_name '(' wfl_expression_list? ')'		wfl_string_escape = "[']" \| '[(]' \| '[)]' ;
			wfl_container = '[' , ['->' \| wfl_expression_list \| wfl_key_value_list] , ']' ;
			wfl_expression_list = wfl_formula , {',' , wfl_formula} ;
			wfl_key_value_list = wml_key_value , {',' , wml_key_value} ;
			wml_key_value = wfl_formula , '->' , wfl_formula ;
			wfl_function_call = wfl_name , '(' , [wfl_expression_list] , ')' ;
			</syntaxhighlight>

	[[Category:WML Reference]]		[[Category:WML Reference]]

Celtic Minstrel: Update opening blurb

2026-03-19T06:17:19Z

Update opening blurb

← Older revision		Revision as of 06:17, 19 March 2026
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	{{WML Tags}}		{{WML Tags}}
	This page contains a formal grammar of the Wesnoth domain-specific languages, including WML and its preprocessor. It does not attempt to capture any of the ways that the Wesnoth engine may interpret a string, such as WML variable substitution. It also doesn't fully capture the potential consequences of macros, for example the use of unbalanced WML tags. The syntax used is ~~regular-expression-like (which is not quite the same as regex-like!), with the following conventions~~:		This page contains a formal grammar of the Wesnoth domain-specific languages, including WML and its preprocessor. It does not attempt to capture any of the ways that the Wesnoth engine may interpret a string, such as WML variable substitution. It also doesn't fully capture the potential consequences of macros, for example the use of unbalanced WML tags. The syntax used is [https://en.wikipedia.org/wiki/Extended_Backus%E2%80%93Naur_form Extended Backus-Naur form].

	* Literal values are enclosed in either 'single quotes' or "double quotes".
	* Square brackets enclose character classes, with initial ^ inverting them
	* Whitespace within an expression (unless quoted) is used only for readability or to separate non-~~terminals~~
	* The meta-characters * + ? \| have the same meaning as is typical in regular expressions
	* The sequence «tab» represents a tab character, and «nl» represents an end-of-line character or character sequence
	* Multiple definitions of a non-terminal are equivalent to alternation (ie, x:=4 and x:=7 combine to produce x:=4\|7)

	== WML Preprocessor ==		== WML Preprocessor ==

Celtic Minstrel: /* WML Substitutions */ Rewrite in EBNF

2026-03-19T06:10:30Z

WML Substitutions: Rewrite in EBNF

← Older revision		Revision as of 06:10, 19 March 2026
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	This grammar describes the syntax of WML substitutions, the syntax used to specify that variables should be substituted into the value of a WML attribute. The grammar here describes a single placeholder, without regard to the fact that they can be nested. Thus, parsing a string using this grammar would only succeed if done from right to left ''while'' performing the substitutions.		This grammar describes the syntax of WML substitutions, the syntax used to specify that variables should be substituted into the value of a WML attribute. The grammar here describes a single placeholder, without regard to the fact that they can be nested. Thus, parsing a string using this grammar would only succeed if done from right to left ''while'' performing the substitutions.

	wml_substitution := wml_var \| wml_formula \| '$\|'		<syntaxhighlight lang=ebnf>
	wml_var := '$' wml_var_path (wml_var_default \| '\|')?		wml_substitution = wml_var \| wml_formula \| '$\|' ;
	wml_var_path := (wml_var_name wml_var_index? '.')* wml_var_name		wml_var = '$' , wml_var_path , [wml_var_default \| '\|'] ;
	wml_var_name := ~~[a-zA-Z0-9_]+~~		wml_var_path = {wml_var_name , [wml_var_index] , '.'} , wml_var_name ;
	wml_var_index := '[' ~~[0-9]+~~ ']'		wml_var_name = wml_id_char, {wml_id_char} ; (* wml_id_char is defined in the WML grammar, above *)
	wml_var_default := '?' [^\|]+ '\|'		wml_var_index = '[' , digit , {digit} , ']' ; (* as is digit *)
	wml_formula := '$' '(' wfl_document ')'		wml_var_default = '?' , default_char, {default_char} , '\|' ;
			default_char = char - '\|' ;
			wml_formula = '$' , '(' , wfl_document , ')' ;
			</syntaxhighlight>

	== Wesnoth Formula Language ==		== Wesnoth Formula Language ==