simple parser in peg.js

simple-parser

start =
    expression

expression =
    _ a:atom
        { return a }
    / _ "(" a:expression b:expression* ")"
        { return [a].concat(b) }
    

validchar = 
    [0-9a-zA-Z_?!+\-=@#$%^&*/.]

atom =
    chars:validchar+
        { return chars.join(""); }
        
_ =
    whitespace*

whitespace =
    [" "]