r7rs-parser

Simple R7RS Scheme parser.

Example

```rust use r7rs_parser::{ parser::Parser, expr::NoIntern};

const SOURCE: &'static str = r#"

!fold-case

(Add 2 3+43i 4145125125153151351351353 3/4) "#;

fn main() { let mut i = NoIntern; let mut parser = Parser::new(&mut i, &SOURCE, false);

while !parser.finished() {
    match parser.parse(true) {
        Ok(expr) => {
            let s = expr.to_string(&NoIntern, false);

            println!("{}", s);
        }
        Err(e) => {
            println!("{}", e);
        }
    }
}

} ```