A parser combinator library for chomping strings (a rune at a time) in Go. A more intuitive way to parse text without having to write a single regex. Happy to chomp both ASCII and Unicode (it all tastes the same).
Inspired by nom 💜.
At the heart of chomp is a combinator. A higher-order function capable of parsing text under a defined condition and returning a tuple (1,2,3):
1: the remaining unparsed (or unchomped) text.2: the parsed (or chomped) text.3: an error if the combinator failed to parse.
Here's a sneak peek at its definition:
type Result interface {
string | []string
}
type Combinator[T Result] func(string) (string, T, error)A combinator in its simplest form would look like this:
func Tag(str string) chomp.Combinator[string] {
return func(s string) (string, string, error) {
if strings.HasPrefix(s, str) {
// Return a tuple containing:
// 1. the remaining string after the prefix
// 2. the matched prefix
// 3. no error
return s[len(str):], str, nil
}
return s, "", chomp.CombinatorParseError{
Input: str,
Text: s,
Type: "tag",
}
}
}The true power of chomp comes from the ability to build parsers by chaining (or combining) combinators together.
Take a look at one of the examples of how to write a parser combinator.
- Combinators are very easy to write and combine into more complex parsers.
- Code written with chomp looks like natural grammar and is easy to understand, maintain and extend.
- It is incredibly easy to unit test.
