parser grammar LeafRefPathParser;

options {
    tokenVocab = LeafRefPathLexer;
}

path_arg : (deref_expr | path_str) EOF;

deref_expr : deref_function_invocation SEP? SLASH SEP? relative_path;

path_str : absolute_path | relative_path;

absolute_path : (SLASH node_identifier (path_predicate)*)+;

relative_path : (DOTS SLASH)* descendant_path;

descendant_path : node_identifier ((path_predicate)* absolute_path)?;

path_predicate : LEFT_SQUARE_BRACKET SEP? path_equality_expr SEP? RIGHT_SQUARE_BRACKET;

path_equality_expr : node_identifier SEP? EQUAL SEP? path_key_expr;

path_key_expr : current_function_invocation SEP? SLASH SEP? rel_path_keyexpr;

rel_path_keyexpr : (DOTS SEP? SLASH SEP?)* (node_identifier SEP? SLASH SEP?)* node_identifier;

node_identifier : (prefix COLON)? identifier;

current_function_invocation : CURRENT_KEYWORD SEP? LEFT_PARENTHESIS SEP? RIGHT_PARENTHESIS;

deref_function_invocation : DEREF_KEYWORD SEP? LEFT_PARENTHESIS SEP? relative_path SEP? RIGHT_PARENTHESIS;

prefix : identifier;

identifier: IDENTIFIER | CURRENT_KEYWORD | DEREF_KEYWORD;