S# - BNF

S# =
    (function),
    {function};

function = ident, params, body;

params = {ident};

body = lbrace, expression, rbrace;

expression =
    number
    | expression, semicolon, expression
    | expression, arithmeticoperator, expression
    | lparen, expression, rparen
    | ifsym, lparen, condition, rparen, body, body // if statement
    | writesym, lparen, expression, rparen, semicolon, expression
    | readsym
    | ident, lparen, expression, rparen; // function

arithmeticoperator = times | slash | plus | minus | mod;

condition =
    truesym
    | falsesym
    | expression, conditionaloperator, expression
    | negation, condition
    | condition, logicaloperator, condition;

logicaloperator = andsym | orsym;

conditionaloperator = eql | neq | lss | gtr;

ident = ? alphanumeric characters ?;
number = ? digits ?;
lbrace = "{";
rbrace = "}";
semicolon = ";";
lparen = "(";
rparen = "}";
writesym = "write";
readsym = "read";
times = "*";
slash = "/";
plus = "+";
minus = "-";
mod = "%";
truesym = "1";
falsesym = "0";
negation = "~";
andsym = "&&";
orsym = "||";
eql = "==";
neq = "!=";
lss = "<";
gtr = ">";