arithmetic_parser_smetaniuk 0.1.2

Arithmetic expression calculator parser.
Documentation 
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// This rule describes a valid number, which can be integer or decimal.
number = @{
    ("0" | ASCII_NONZERO_DIGIT ~ ASCII_DIGIT*)
    ~ ("." ~ ASCII_DIGIT*)?
}

// This rule represents the unary minus operator.
unary_minus = { "-" }

// This rule represents the primary expression, which can be a number or an enclosed expression.
primary = _{ number | "(" ~ expr ~ ")" }

// This rule represents the atom, which can be a primary expression with an optional unary minus.
atom = _{ unary_minus? ~ primary }

// This rule represents the binary operators, including add, subtract, multiply, and divide.
bin_op = _{ add | subtract | multiply | divide }
  add = { "+" }
  subtract = { "-" }
  multiply = { "*" }
  divide = { "/" }

// This rule represents the overall expression, composed of atoms and binary operators.
expr = { atom ~ (bin_op ~ atom)* }

// This rule represents an equation, starting and ending with specific markers and having an expression in between.
equation = _{ SOI ~ expr ~ EOI }

// This rule defines whitespace as a space character.
WHITESPACE = _{ " " }