diff options
Diffstat (limited to 'parse.go')
| -rw-r--r-- | parse.go | 49 |
1 files changed, 38 insertions, 11 deletions
@@ -21,7 +21,6 @@ type spec struct { env string wasPresent bool boolean bool - fieldName string // for generating helpful errors } // ErrHelp indicates that -h or --help were provided @@ -81,6 +80,19 @@ type Versioned interface { Version() string } +// walkFields calls a function for each field of a struct, recursively expanding struct fields. +func walkFields(v reflect.Value, visit func(field reflect.StructField, val reflect.Value, owner reflect.Type) bool) { + t := v.Type() + for i := 0; i < t.NumField(); i++ { + field := t.Field(i) + val := v.Field(i) + expand := visit(field, val, t) + if expand && field.Type.Kind() == reflect.Struct { + walkFields(val, visit) + } + } +} + // NewParser constructs a parser from a list of destination structs func NewParser(config Config, dests ...interface{}) (*Parser, error) { p := Parser{ @@ -99,19 +111,22 @@ func NewParser(config Config, dests ...interface{}) (*Parser, error) { panic(fmt.Sprintf("%T is not a struct pointer", dest)) } - t := v.Type() - for i := 0; i < t.NumField(); i++ { + var errs []string + walkFields(v, func(field reflect.StructField, val reflect.Value, t reflect.Type) bool { // Check for the ignore switch in the tag - field := t.Field(i) tag := field.Tag.Get("arg") if tag == "-" { - continue + return false + } + + // If this is an embedded struct then recurse into its fields + if field.Anonymous && field.Type.Kind() == reflect.Struct { + return true } spec := spec{ - long: strings.ToLower(field.Name), - dest: v.Field(i), - fieldName: t.Name() + "." + field.Name, + long: strings.ToLower(field.Name), + dest: val, } // Check whether this field is supported. It's good to do this here rather than @@ -121,7 +136,9 @@ func NewParser(config Config, dests ...interface{}) (*Parser, error) { var parseable bool parseable, spec.boolean, spec.multiple = canParse(field.Type) if !parseable { - return nil, fmt.Errorf("%s.%s: %s fields are not supported", t.Name(), field.Name, field.Type.String()) + errs = append(errs, fmt.Sprintf("%s.%s: %s fields are not supported", + t.Name(), field.Name, field.Type.String())) + return false } // Look at the tag @@ -138,7 +155,9 @@ func NewParser(config Config, dests ...interface{}) (*Parser, error) { spec.long = key[2:] case strings.HasPrefix(key, "-"): if len(key) != 2 { - return nil, fmt.Errorf("%s.%s: short arguments must be one character only", t.Name(), field.Name) + errs = append(errs, fmt.Sprintf("%s.%s: short arguments must be one character only", + t.Name(), field.Name)) + return false } spec.short = key[1:] case key == "required": @@ -155,11 +174,19 @@ func NewParser(config Config, dests ...interface{}) (*Parser, error) { spec.env = strings.ToUpper(field.Name) } default: - return nil, fmt.Errorf("unrecognized tag '%s' on field %s", key, tag) + errs = append(errs, fmt.Sprintf("unrecognized tag '%s' on field %s", key, tag)) + return false } } } p.spec = append(p.spec, &spec) + + // if this was an embedded field then we already returned true up above + return false + }) + + if len(errs) > 0 { + return nil, errors.New(strings.Join(errs, "\n")) } } if p.config.Program == "" { |