package eval import ( "github.com/elves/elvish/pkg/parse" ) func onePrimary(cn *parse.Compound) *parse.Primary { if len(cn.Indexings) == 1 && len(cn.Indexings[0].Indicies) == 0 { return cn.Indexings[0].Head } return nil } func oneString(cn *parse.Compound) (string, bool) { pn := onePrimary(cn) if pn != nil { switch pn.Type { case parse.Bareword, parse.SingleQuoted, parse.DoubleQuoted: return pn.Value, true } } return "", false } // mustString musts that a Compound contains exactly one Primary of type // Variable. func mustString(cp *compiler, cn *parse.Compound, msg string) string { s, ok := oneString(cn) if !ok { cp.errorpf(cn, msg) } return s }