literal = @{('a' .. 'z' | 'A' .. 'Z' | '0' .. '9' | "-" | "_" | "`" | "~" | "+" | "#" | "%" | "$" | "^" | "/" | ":")+}

string = _{("'" ~ (string_value) ~ "'") | ("\"" ~ (string_value) ~ "\"") | ("\"" ~ (string_value_escape_1) ~ "\"") | ("'" ~ (string_value_escape_2) ~ "'")}
    string_escape = @{"\\"}
    string_value = @{((!("\""|"\\"|"'") ~ ANY)+)*}
    string_value_escape_1 = @{((!("\""|"\\") ~ ANY)+ | string_escape ~ ("\"" | "\\"))*}
    string_value_escape_2 = @{((!("'"|"\\") ~ ANY)+ | string_escape ~ ("'" | "\\"))*}

string_list = {string ~ ("," ~ string)*}

pos_number = @{ASCII_NONZERO_DIGIT ~ ASCII_DIGIT*}
number = @{"-"? ~ ASCII_NONZERO_DIGIT ~ ASCII_DIGIT* | "-"? ~ ASCII_DIGIT}

decimal = @{number ~ ("." ~ ASCII_DIGIT+)?}

numbers_list = {number ~ ("," ~ number)*}

numbers_range = {(full_range | right_range | all_range | left_range)}
    right_range = {":" ~ number ~ ((":" ~ pos_number) | ":")?}
    all_range = {":" ~ ((":" ~ pos_number) | ":")?}
    left_range = {number ~ ":"  ~ ((":" ~ pos_number) | ":")?}
    full_range = {number ~ ":" ~ number  ~ ((":" ~ pos_number) | ":")?}

from_current = {"@" ~ root?}
from_root    = {"$" ~ root?}

select_term = _{from_current | from_root}

op = _{ge | gt | le | lt | eq | ne | re}
    ge = @{">="}
    gt = @{">"}
    le = @{"<="}
    lt = @{"<"}
    eq = @{"=="}
    ne = @{"!="}
    re = @{"=~"}

boolean = _{boolean_true | boolean_false}
    boolean_true = @{"true"}
    boolean_false = @{"false"}

term = _{select_term | decimal | string | boolean}

single_filter = {term ~ op ~ term | term}

filter_relation = _{and | or}
    and = {"&&"}
    or  = {"||"}

inner_filter = _{single_filter | "(" ~ filter ~ ")"}

filter = {inner_filter ~ (filter_relation ~ inner_filter)*}

all = {"*"}

full_scan = {".."}

bracket = _{numbers_range | numbers_list | string_list | all | "?" ~ filter}

element = _{"." ~ literal | full_scan ~ (literal | all | "[" ~ bracket ~ "]") | "." ~ all | ("."? ~ "[" ~ bracket ~ "]")}

first_element = _{literal | all}

root = {(element|first_element) ~ (element)*}

simple_root = {"." ~ literal}

query = _{SOI ~ "$" ~ root? ~ EOI}

simple_query = _{SOI ~ "$" ~ simple_root ~ EOI}

WHITESPACE = _{ " " }