Function parse

leanr-syntax/src/parser.rs:734–739

(input: &str)

    use crate::span::SourceFile;

    fn parse(input: &str) -> crate::Result<Vec<Decl>> {
        let source = SourceFile::new(0, "test.lean".to_string(), input.to_string());
        let tokens = Lexer::new(source).tokenize();
        let mut parser = Parser::new(tokens);
        parser.parse_decls()
    }

    #[test]
    fn test_simple_def() {