Function parse 

pub fn parse(input: &str) -> ParseResult

Parse a CEL expression from source.

Returns a ParseResult which may contain both a partial AST and errors when error recovery is successful. Macros (has, all, exists, exists_one, map, filter) are expanded inline during parsing.

The macro_calls field in the result maps comprehension/expansion IDs to the original macro call expressions, which is useful for IDE features.