tree-sitter-lbnf.ebnf

//
// From tree-sitter-lbnf/src/grammar.json
//
//
// EBNF to generate railroad diagram at 
//      (IPV6) https://www.bottlecaps.de/rr/ui
//      (IPV4) https://rr.red-dove.com/ui
//

grammar ::=
	 ( def ';' )*

def ::=
	 label '.' cat '::=' item*
	| 'comment' string
	| 'comment' string string
	| 'internal' label '.' cat '::=' item*
	| 'token' ident reg
	| 'position' 'token' ident reg
	| 'entrypoints' ident ( ',' ident )*
	| 'separator' 'nonempty'? cat string
	| 'terminator' 'nonempty'? cat string
	| 'coercions' ident integer
	| 'rules' ident '::=' item* ( '|' item* )*
	| 'layout' string ( ',' string )*
	| 'layout' 'stop' string ( ',' string )*
	| 'layout' 'toplevel'

item ::=
	 string
	| cat

cat ::=
	 '[' cat ']'
	| ident

label ::=
	 label_id
	| label_id prof_item*
	| label_id label_id prof_item*

label_id ::=
	 ident
	| '_'
	| '[' ']'
	| '(' ':' ')'
	| '(' ':' '[' ']' ')'

prof_item ::=
	 '(' '[' ( int_list ( ',' int_list )* )? ']' ',' '[' ( integer ( ',' integer )* )? ']' ')'

int_list ::=
	 '[' ( integer ( ',' integer )* )? ']'

reg2 ::=
	 reg2 reg3
	| reg3

reg1 ::=
	 reg1 '|' reg2
	| reg2 '-' reg2
	| reg2

reg3 ::=
	 reg3 '*'
	| reg3 '+'
	| reg3 '?'
	| 'eps'
	| char
	| '[' string ']'
	| '{' string '}'
	| 'digit'
	| 'letter'
	| 'upper'
	| 'lower'
	| 'char'
	| '(' reg ')'

reg ::=
	 reg1

integer ::=
	 [0-9]+

char ::=
	 "'"  ( escape_sequence | [^#x0A'] ) "'" 

string ::=
	 '"'  ( [^\"#x0A]+ | escape_sequence )* '"' 

escape_sequence ::=
	 ( '\\'  ( [^xuU] | [0-9]'{2,3}' | 'x'[0-9a-fA-F]'{2,}' | 'u'[0-9a-fA-F]'{4}' | 'U'[0-9a-fA-F]'{8}' ) )

ident ::=
	 [a-zA-Z][a-zA-Z_]*

comment ::=
	 ( '--' '.'* | '{-' ( [^-] | '-'[^}] )* '-}' )