-- This is the labelled bnf of fstStudio.

-- Two things that exists in XFST are not added:

-- * parallel replacement.

-- * substitution.

Prog . Program ::= [Def] ;

Declaration . Def ::= "<" Ident [Ident] ">" "::=" Exp ;

Main . Def ::= "<" "main" ">" "::=" Exp ;

Import . Def ::= "import" [Ident] ;

LongReplace . Exp ::= Exp "@->" Exp1 ;

Restriction . Exp ::= Exp "=>" Exp1 "_" Exp1 ;

Replacement . Exp ::= Exp "->" Exp1 ;

CReplacement . Exp ::= Exp "->" Exp1 "||" Exp1 "_" Exp1 ;

CSReplacement . Exp ::= Exp "->" Exp1 "//" Exp1 "_" Exp1 ;

Composition . Exp ::= Exp ".o." Exp1 ;

CrossProduct . Exp ::= Exp ".x." Exp1 ;

_ . Exp ::= Exp1 ;

Markup . Exp1 ::= Exp2 "..." Exp2 ; -- for replacement

Minus . Exp1 ::= Exp1 "-" Exp2 ;

Intersect . Exp1 ::= Exp1 "&" Exp2 ;

Union . Exp1 ::= Exp1 "|" Exp2 ;

_ . Exp1 ::= Exp2 ;

Concat . Exp2 ::= Exp2 Exp3 ;

_ . Exp2 ::= Exp3 ;

Containment . Exp3 ::= "$" Exp4 ;

TComplement . Exp3 ::= "\\" Exp4 ;

Complement . Exp3 ::= "~" Exp4 ;

_ . Exp3 ::= Exp4 ;

NConcat . Exp4 ::= Exp4 "^" Integer ;

AppDecl . Exp4 ::= "<" Ident [Exp] ">" ;

Star . Exp4 ::= Exp4 "*" ;

Plus . Exp4 ::= Exp4 "+" ;

Symbol . Exp4 ::= String ;

Variable . Exp4 ::= Ident;

Concats . Exp4 ::= "{" String "}" ;

Any . Exp4 ::= "?" ;

Epsilon . Exp4 ::= "0" ;

Relation . Exp4 ::= String ":" String ;

Boundary . Exp4 ::= ".#." ;

_ . Exp4 ::= "(" Exp ")" ;

[] . [Def] ::= ;

(:) . [Def] ::= Def ";" [Def] ;

[] . [Exp] ::= ;

(:) . [Exp] ::= "," Exp [Exp] ;

[] . [Ident] ::= ;

(:) . [Ident] ::= "," Ident [Ident] ;

comment "--" ;

comment "{-" "-}" ;