# grammar file for basil
#

# start rule
start -> rule-seq-opt

# rule seq opt
rule-seq-opt -> 
rule-seq-opt -> rule-seq

# rule seq
rule-seq -> rule
rule-seq -> rule-seq rule

# rule 
# first try right-hand side symbol then left-hand side symbol
# reduce only if valid token is next
[RuleNode] rule <* -> rule-name-opt symbol ARROW symbol-seq-opt >

# node name opt
rule-name-opt -> rule-name
rule-name-opt ->

# node name
[NodeName1Node] rule-name -> LBRACK slip-spec-opt IDENT RBRACK
[NodeName2Node] rule-name -> LBRACK LPAREN IDENT RPAREN RBRACK
[NodeName3Node] rule-name -> LBRACK RBRACK

# slip specifier opt
slip-spec-opt -> slip-spec
slip-spec-opt ->

# slip spec
slip-spec -> DOLLAR

# symbol sequence opt
symbol-seq-opt ->
symbol-seq-opt -> symbol-seq

# symbol sequence
symbol-seq -> symbol
[$ SeqNode] symbol-seq -> symbol-seq symbol

# symbol
[SymbolNode] symbol -> IDENT attrib-seq-opt

# attrib seq opt 
attrib-seq-opt ->
attrib-seq-opt -> attrib-seq

# attrib seq
attrib-seq -> attrib
[(SeqNode)] attrib-seq -> attrib-seq attrib

# attribute
[Attrib1Node] attrib -> GT
[Attrib2Node] attrib -> PLUS
[Attrib3Node] attrib -> NUMBER
[Attrib4Node] attrib -> STAR
[Attrib5Node] attrib -> LT
[Attrib6Node] attrib -> CARET
[Attrib7Node] attrib -> LPAREN attrib-seq RPAREN NUMBER
[Attrib8Node] attrib -> BANG