textfmt/write.go

package textfmt

import (
	"bytes"
	"code.squareroundforest.org/arpio/textedit"
	"fmt"
	"io"
)

type wrapper func(io.Writer) (io.Writer, func() error)

type errorWriter struct {
	out io.Writer
	err error
}

func (w *errorWriter) Write(p []byte) (int, error) {
	if w.err != nil {
		return 0, w.err
	}

	var n int
	n, w.err = w.out.Write(p)
	return n, w.err
}

func writeWith(out io.Writer, w ...wrapper) (io.Writer, func() (io.Writer, error)) {
	f := make([]func() error, len(w))
	ww := out
	for i := len(w) - 1; i >= 0; i-- {
		var fi func() error
		ww, fi = w[i](ww)
		f[i] = fi
	}

	return ww, func() (io.Writer, error) {
		for _, fi := range f {
			if err := fi(); err != nil {
				return out, err
			}
		}

		return out, nil
	}
}

func errorHandler(out io.Writer) (io.Writer, func() error) {
	ew := errorWriter{out: out}
	return &ew, func() error { return ew.err }
}

func editor(e textedit.Editor) wrapper {
	return func(out io.Writer) (io.Writer, func() error) {
		ew := textedit.New(out, e)
		return ew, func() error { return ew.Flush() }
	}
}

func editString(s string, e ...wrapper) string {
	var b bytes.Buffer
	w, finish := writeWith(&b, e...)
	w.Write([]byte(s))
	finish()
	return b.String()
}

func ttyNBSP() wrapper    { return editor(textedit.Replace("\u00a0", " ")) }
func roffNBSP() wrapper   { return editor(textedit.Replace("\u00a0", "\\~")) }
func mdNBSP() wrapper     { return editor(textedit.Replace("\u00a0", " ")) }
func singleLine() wrapper { return editor(textedit.SingleLine()) }

func indent(first, rest int) wrapper {
	return editor(textedit.Indent(timesn(" ", first), timesn(" ", rest)))
}

func wrap(firstWidth, restWidth int) wrapper {
	return editor(textedit.Wrap(firstWidth, restWidth))
}

func wrapIndent(first, rest, firstWidth, restWidth int) wrapper {
	return editor(textedit.WrapIndent(timesn(" ", first), timesn(" ", rest), firstWidth, restWidth))
}

func write(out io.Writer, a ...any) {
	for _, ai := range a {
		if _, err := out.Write([]byte(fmt.Sprint(ai))); err != nil {
			return
		}
	}
}