/
builtin_fn_styled.go
100 lines (84 loc) · 2.55 KB
/
builtin_fn_styled.go
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package eval
import (
"errors"
"fmt"
"github.com/elves/elvish/eval/vals"
"github.com/elves/elvish/styled"
)
var errStyledSegmentArgType = errors.New("argument to styled-segment must be a string or a styled segment")
func init() {
addBuiltinFns(map[string]interface{}{
"styled-segment": styledSegment,
"styled": Styled,
})
}
// Turns a string or styled Segment into a new styled Segment with the attributes
// from the supplied options applied to it. If the input is already a Segment its
// attributes are copied and modified.
func styledSegment(options RawOptions, input interface{}) (*styled.Segment, error) {
var text string
var style styled.Style
switch input := input.(type) {
case string:
text = input
case *styled.Segment:
text = input.Text
style = input.Style
default:
return nil, errStyledSegmentArgType
}
if err := style.ImportFromOptions(options); err != nil {
return nil, err
}
return &styled.Segment{
Text: text,
Style: style,
}, nil
}
// Styled turns a string, a styled Segment or a styled Text into a styled Text.
// This is done by applying a range of transformers to the input.
func Styled(fm *Frame, input interface{}, transformers ...interface{}) (*styled.Text, error) {
var text styled.Text
switch input := input.(type) {
case string:
text = styled.Text{styled.Segment{
Text: input,
Style: styled.Style{},
}}
case *styled.Segment:
text = styled.Text{*input}
case *styled.Text:
text = *input
default:
return nil, fmt.Errorf("expected string, styled segment or styled text; got %s", vals.Kind(input))
}
for _, transformer := range transformers {
switch transformer := transformer.(type) {
case string:
transformerFn := styled.FindTransformer(transformer)
if transformerFn == nil {
return nil, fmt.Errorf("'%s' is no valid style transformer", transformer)
}
for i, segment := range text {
text[i] = transformerFn(segment)
}
case Callable:
for i, segment := range text {
vs, err := fm.CaptureOutput(transformer, []interface{}{&segment}, NoOpts)
if err != nil {
return nil, err
}
if n := len(vs); n != 1 {
return nil, fmt.Errorf("style transformers must return a single styled segment; got %d", n)
} else if transformedSegment, ok := vs[0].(*styled.Segment); !ok {
return nil, fmt.Errorf("style transformers must return a styled segment; got %s", vals.Kind(vs[0]))
} else {
text[i] = *transformedSegment
}
}
default:
return nil, fmt.Errorf("need string or callable; got %s", vals.Kind(transformer))
}
}
return &text, nil
}