WHITESPACE = _{ " " | "\t" | NEWLINE }
COMMENT    = _{ ("//" ~ (!NEWLINE ~ ANY)*) | ("/*" ~ (!"*/" ~ ANY)* ~ "*/") }

boolean_literal       = @{ "true" | "false" }
number_literal        = @{ "-"? ~ ASCII_DIGIT+ ~ ("." ~ ASCII_DIGIT+)? }
string_literal        = @{ "\"" ~ ("\\\"" | (!"\"" ~ ANY))* ~ "\"" }
format_string         = @{ "$\"" ~ ("\\\"" | (!("{" | NEWLINE) ~ ANY))* ~ "\"" }
format_string_part1   = @{ "$\"" ~ ("\\\"" | (!("{" | NEWLINE) ~ ANY))* ~ "{" }
format_string_part2   = @{ "}" ~ ("\\\"" | (!("{" | NEWLINE) ~ ANY))* ~ "{" }
format_string_part3   = @{ "}" ~ ("\\\"" | (!("\"" | NEWLINE) ~ ANY))* ~ "\"" }
format_string_literal =  { format_string | (format_string_part1 ~ expr ~ (format_string_part2 ~ expr)* ~ format_string_part3) }
literal               =  { boolean_literal | number_literal | string_literal | format_string_literal }

id      = { (ASCII_ALPHA | "_") ~ (ASCII_ALPHANUMERIC | "_")* }
ids     = { id ~ ("." ~ id)* }
anno_if = { "@if" ~ expr }

op2         = { "+" | "-" | "*" | "/" | "**" | "%" | "|" | "&" | "||" | "&&" | "<<" | ">>" | "^" | "<" | "<=" | ">" | ">=" | "==" | "!=" }
base_expr   = { literal | ids | ("(" ~ expr ~ ")") }
_exprs      = { (expr ~ ("," ~ expr)*)? }
array_expr  = { "[" ~ _exprs ~ "]" }
map_expr    = { "{" ~ (map_assign_pair ~ ("," ~ map_assign_pair)*)* ~ "}" }
strong_expr = { base_expr | array_expr | map_expr }
expr_prefix = { "++" | "--" | "!" | "-" | "~" }
expr_suffix = { ("." ~ id ~ ("(" ~ _exprs ~ ")")?) | "++" | "--" }
middle_expr = { expr_prefix* ~ strong_expr ~ expr_suffix* }
weak_expr   = { middle_expr ~ (op2 ~ middle_expr)* }
op3_expr    = { middle_expr ~ "?" ~ middle_expr ~ ":" ~ middle_expr }
expr        = { weak_expr | op3_expr }

assign_pair     = { anno_if? ~ ids ~ "=" ~ expr }
map_assign_pair = { ids ~ ":" ~ expr }

group_head       = { "[" ~ ids ~ "]" }
group_array_head = { "[[" ~ ids ~ "]]" }
group_block      = { anno_if? ~ (group_head | group_array_head) ~ assign_pair* }

oml = { SOI ~ (group_block)* ~ EOI }