m64 0.0.5

// Non-token characters
de_ref = _{ "*" }
make_ref = _ { "&" }
backslash = _{ "\\" }
comma = _{ "," }
double_quote = _{ "\"" }
single_quote = _{ "'" }
not_newline = { !NEWLINE ~ ANY }
WHITESPACE = _{ " " | "\t" }
COMMENT = _{ ";" ~ not_newline* }

// Literals
dec_literal = @{ ASCII_DIGIT+ }
bin_literal = @{ ^"0b" ~ ASCII_BIN_DIGIT+ }
hex_literal = @{ ^"0x" ~ ASCII_HEX_DIGIT+ }
char_literal = @{ single_quote ~ backslash? ~ ASCII ~ single_quote }
int_literal = { bin_literal | hex_literal | dec_literal | char_literal }
string_literal = @{ double_quote ~ (!double_quote ~ ASCII)* ~ double_quote }
literal = { int_literal | string_literal }

// Pointers / addresses
address = ${ de_ref ~ (int_literal | register) }

// Registers
register_index = @{ ASCII_HEX_DIGIT }
register = ${ ^"x" ~ register_index }

// Instructions
operation = @{ LETTER{3,4} }
argument = {
    int_literal | address | register | label
}
instruction = { operation ~ ((argument ~ comma)* ~ argument)? }

// Labels
label = @{ ("." | "@")? ~ (ASCII_ALPHANUMERIC | "_")+ }
label_definition = { label ~ ":" }

// Program structure
statement = { (label_definition | instruction) ~ (NEWLINE+ | &EOI) }
file = {
    SOI ~ NEWLINE* ~
    statement* ~
    &EOI
}