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package ui
import "strings"
// Methods of [TextBuilder] are fully exercised by other functions Concat, so
// there are no dedicated tests for it.
// TextBuilder can be used to efficiently build a [Text]. The zero value is
// ready to use. Do not copy a non-zero TextBuilder.
type TextBuilder struct {
segs []*Segment
style Style
text strings.Builder
}
// WriteText appends t to the TextBuilder.
func (tb *TextBuilder) WriteText(t Text) {
if len(t) == 0 {
return
}
if tb.style == t[0].Style {
// Merge the first segment of t with the pending segment.
tb.text.WriteString(t[0].Text)
t = t[1:]
if len(t) == 0 {
return
}
}
// At this point, the first segment of t has a different style than the
// pending segment (assuming that t is normal). Add the pending segment if
// it's non-empty.
if tb.text.Len() > 0 {
tb.segs = append(tb.segs, &Segment{tb.style, tb.text.String()})
tb.text.Reset()
}
// Add all segments from t except the last one.
tb.segs = append(tb.segs, t[:len(t)-1]...)
// Use the last segment of t as the pending segment.
tb.style = t[len(t)-1].Style
tb.text.WriteString(t[len(t)-1].Text)
}
// Text returns the [Text] that has been built.
func (tb *TextBuilder) Text() Text {
if tb.Empty() {
return nil
}
t := append(Text(nil), tb.segs...)
return append(t, &Segment{tb.style, tb.text.String()})
}
// Empty returns nothing has been written to the TextBuilder yet.
func (tb *TextBuilder) Empty() bool {
return len(tb.segs) == 0 && tb.text.Len() == 0
}
// Reset resets the TextBuilder to be empty.
func (tb *TextBuilder) Reset() {
tb.segs = nil
tb.style = Style{}
tb.text.Reset()
}
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