Using interface as type about participle

[alecthomas]

You're welcome!

I don't see how that would work in practice, as Participle constructs the fields itself. With an empty interface it will never know what to construct.

If you want to customise parsing there are a couple of options: the Capture interface and the Parseable interface. The former can be used to process tokens captured by the grammar (eg. @String) while the latter can be used to capture anything directly from the lexer.

[zubazuba]

@alecthomas if you don't mind, how exactly could I implement the capture interface?

[alecthomas]

Something like this:

type AST struct {
  Colour *Colour `@Ident`
}

type Colour struct {
  Colour string
}

func (c *Colour) Capture(tokens []string) error {
  if tokens[0] != "red" {
    return fmt.Errorf("colour must be red")
  }
  c.Colour = tokens[0]
  return nil
}

[zubazuba]

Thank you, I will try it.