start: seq (attr_sep global_attr)* WS?
seq: (WS|monomer)((WS? nick)? (WS|monomer))*
?monomer: alphabet_monomer | inline_monomer
alphabet_monomer: CHAR | DELIMITED_CHARS
inline_monomer: OPEN_SQ_BRACKET WS? inline_monomer_attr (attr_sep inline_monomer_attr)* WS? CLOSE_SQ_BRACKET
?inline_monomer_attr: id | name | synonym | identifier | structure | backbone_bond_atom | backbone_displaced_atom | r_bond_atom | l_bond_atom | r_displaced_atom | l_displaced_atom | delta_mass | delta_charge | position | base_monomer | comments
id: ID_FIELD_NAME field_sep ESCAPED_STRING
name: NAME_FIELD_NAME field_sep ESCAPED_STRING
synonym: SYNONYM_FIELD_NAME field_sep ESCAPED_STRING
identifier: IDENTIFIER_FIELD_NAME field_sep identifier_id identifier_sep identifier_ns
?identifier_ns: ESCAPED_STRING
?identifier_id: ESCAPED_STRING
structure: STRUCTURE_FIELD_NAME field_sep QUOTE_DELIMITER SMILES QUOTE_DELIMITER
backbone_bond_atom: BACKBONE_BOND_ATOM_FIELD_NAME field_sep atom
backbone_displaced_atom: BACKBONE_DISPLACED_ATOM_FIELD_NAME field_sep atom
r_bond_atom: RIGHT_BOND_ATOM_FIELD_NAME field_sep atom
l_bond_atom: LEFT_BOND_ATOM_FIELD_NAME field_sep atom
r_displaced_atom: RIGHT_DISPLACED_ATOM_FIELD_NAME field_sep atom
l_displaced_atom: LEFT_DISPLACED_ATOM_FIELD_NAME field_sep atom
atom: atom_element INT atom_charge?
?atom_element: /[A-Z][a-z]?/
?atom_charge: /[\+\-][0-9]+/
delta_mass: DELTA_MASS_FIELD_NAME field_sep DALTON
delta_charge: DELTA_CHARGE_FIELD_NAME field_sep CHARGE
position: POSITION_FIELD_NAME field_sep INT? DASH INT? monomers_position?
monomers_position: WS? OPEN_SQ_BRACKET (CHAR|CHARS) (WS? "|" WS? (CHAR|CHARS))* CLOSE_SQ_BRACKET
base_monomer: BASE_MONOMER_FIELD_NAME field_sep QUOTE_DELIMITER (CHAR|CHARS) QUOTE_DELIMITER
comments: COMMENTS_FIELD_NAME field_sep ESCAPED_STRING
?global_attr: crosslink | circular

crosslink: CROSSLINK_FIELD_NAME field_sep OPEN_SQ_BRACKET WS? (onto_crosslink | inline_crosslink) WS? CLOSE_SQ_BRACKET

onto_crosslink: onto_crosslink_attr (attr_sep onto_crosslink_attr)*
onto_crosslink_attr: onto_crosslink_type | onto_crosslink_monomer
onto_crosslink_monomer: onto_crosslink_monomer_type field_sep INT
onto_crosslink_monomer_type: /[lr]/
onto_crosslink_type: "type" field_sep QUOTE_DELIMITER CHARS QUOTE_DELIMITER

inline_crosslink: (inline_crosslink_attr (attr_sep inline_crosslink_attr)*)?
inline_crosslink_attr: inline_crosslink_atom | inline_crosslink_order | inline_crosslink_stereo | inline_crosslink_comments
inline_crosslink_atom: inline_crosslink_atom_type field_sep INT atom_element INT atom_charge?
inline_crosslink_atom_type: (LEFT_BOND_ATOM_FIELD_NAME | RIGHT_BOND_ATOM_FIELD_NAME | LEFT_DISPLACED_ATOM_FIELD_NAME | RIGHT_DISPLACED_ATOM_FIELD_NAME)
inline_crosslink_order: "order" field_sep QUOTE_DELIMITER /(single|double|triple|aromatic)/ QUOTE_DELIMITER
inline_crosslink_stereo: "stereo" field_sep QUOTE_DELIMITER /(wedge|hash|up|down)/ QUOTE_DELIMITER
inline_crosslink_comments: COMMENTS_FIELD_NAME field_sep ESCAPED_STRING

nick: ":"

circular: "circular"

ID_FIELD_NAME: "id"
NAME_FIELD_NAME: "name"
SYNONYM_FIELD_NAME: "synonym"
IDENTIFIER_FIELD_NAME: "identifier"
STRUCTURE_FIELD_NAME: "structure"
BACKBONE_BOND_ATOM_FIELD_NAME: "backbone-bond-atom"
BACKBONE_DISPLACED_ATOM_FIELD_NAME: "backbone-displaced-atom"
LEFT_BOND_ATOM_FIELD_NAME: "l-bond-atom"
LEFT_DISPLACED_ATOM_FIELD_NAME: "l-displaced-atom"
RIGHT_BOND_ATOM_FIELD_NAME: "r-bond-atom"
RIGHT_DISPLACED_ATOM_FIELD_NAME: "r-displaced-atom"
DELTA_MASS_FIELD_NAME: "delta-mass"
DELTA_CHARGE_FIELD_NAME: "delta-charge"
POSITION_FIELD_NAME: "position"
BASE_MONOMER_FIELD_NAME: "base-monomer"
COMMENTS_FIELD_NAME: "comments"
CROSSLINK_FIELD_NAME: "x-link"

?attr_sep: WS? "|" WS?
?field_sep: WS? ":" WS?
?identifier_sep: WS? "@" WS?

CHAR: /[^\[\]\{\}":\| \t\f\r\n]/
CHARS: CHAR /[^\[\]\{\}":\|\t\f\r\n]*/ CHAR
DELIMITED_CHARS: "{" (CHAR|CHARS) "}"
SMILES: /[^"]+/
DALTON: /[\-\+]?[0-9]+(\.[0-9]*)?/
CHARGE: /[\-\+]?[0-9]+/
OPEN_SQ_BRACKET: "["
CLOSE_SQ_BRACKET: "]"
QUOTE_DELIMITER: "\""
DASH: "-"
WS: /[ \t\f\r\n]+/
INT: /[0-9]+/
ESCAPED_STRING: /"(?:[^"\\]|\\.)*"/