Function parse 

pub fn parse(input: &str) -> Result<EmlTree, ParseError>

Parse an EML expression string into an EmlTree.

Accepts both E(x, y) and eml(x, y) notation.

Examples

use oxieml::parser::parse;

let tree = parse("E(1, 1)").unwrap();
assert_eq!(tree.depth(), 1);

let tree = parse("eml(E(1, 1), 1)").unwrap();
assert_eq!(tree.depth(), 2);