Pascal.js ФБН

ФБН поддерживаемых выражений на момент старта работы с репозиторием
Добавил унарный минус, скобки, переменные

<Digit> ::= [0-9] 
<UnsignedInteger> ::= "0" | ([1-9] <Digit>*)
<Variable> ::= "a" | "b" | "c"
<Multiplier> ::= "-"? (<UnsignedInteger> | <Variable> | "(" <Expression> ")")
<Multiplication> ::= ( <Multiplier> | <Multiplication> | <Division> ) "*" <Multiplier>
<Division> ::= ( <Multiplier> | <Multiplication> | <Division> ) "/" <Multiplier>
<Term> ::= <Multiplier> | <Multiplication> | <Division>
<Addition> ::= ( <Term> | <Addition> | <Subtraction> ) "+" <Term>
<Subtraction> ::= ( <Term> | <Addition> | <Subtraction> ) "-" <Term>
<Expression> ::= <Term> | <Addition> | <Subtraction>
<Assignment> ::= <Variable> "=" <Expression>


<Digit> ::= [0-9] 
<UnsignedInteger> ::= "0" | ([1-9] <Digit>*)
<Variable> ::= "a" | "b" | "c"
<Multiplier> ::= "-"? (<UnsignedInteger> | <Variable> | "(" <Expression> ")")
<Multiplication> ::= ( <Multiplier> | <Multiplication> | <Division> ) "*" <Multiplier>
<Division> ::= ( <Multiplier> | <Multiplication> | <Division> ) "/" <Multiplier>
<Term> ::= <Multiplier> | <Multiplication> | <Division>
<Addition> ::= ( <Term> | <Addition> | <Subtraction> ) "+" <Term>
<Subtraction> ::= ( <Term> | <Addition> | <Subtraction> ) "-" <Term>
<Expression> ::= <Term> | <Addition> | <Subtraction>
<Equality> ::= <Expression> "=" <Expression>