This parser is no longer maintained. Too many technical debts have accumulated over time. Instead of an extensive re-factorization, I decided to take only the tokenizer and redevelop the parser, and separate the parser and code generator (actually a function generator).
See parser2
A simple parser that is able to parse expressions. It is configurable to many use cases. It supports a generic value type. This allows a dynamic type system, which requires runtime type checking.
The file float.go contains a simple example of a float based expression parser and the packages valErr and dynType contain two more advanced example parsers.