elvish/eval/glob.go

package eval

import (
	"errors"
	"fmt"

	"github.com/elves/elvish/glob"
)

// GlobPattern is en ephemeral Value generated when evaluating tilde and
// wildcards.
type GlobPattern glob.Pattern

var (
	_ Value   = GlobPattern{}
	_ Indexer = GlobPattern{}
)

var (
	ErrMustFollowWildcard   = errors.New("must follow wildcard")
	ErrModifierMustBeString = errors.New("modifier must be string")
)

func (GlobPattern) Kind() string {
	return "glob-pattern"
}

func (gp GlobPattern) Repr(int) string {
	return fmt.Sprintf("<GlobPattern%v>", gp)
}

func (gp GlobPattern) Index(modifiers []Value) []Value {
	for _, value := range modifiers {
		modifier, ok := value.(String)
		if !ok {
			throw(ErrModifierMustBeString)
		}
		switch string(modifier) {
		case "a", "all":
			if len(gp.Segments) == 0 {
				throw(ErrBadGlobPattern)
			}
			t := gp.Segments[len(gp.Segments)-1].Type
			if t != glob.Question && t != glob.Star && t != glob.StarStar {
				throw(ErrMustFollowWildcard)
			}
			gp.Segments[len(gp.Segments)-1].Data = "all"
		default:
			throw(fmt.Errorf("unknown modifier %s", modifier.Repr(NoPretty)))
		}
	}
	return []Value{gp}
}

func (gp *GlobPattern) append(segs ...glob.Segment) {
	gp.Segments = append(gp.Segments, segs...)
}

func wildcardToSegment(s string) glob.Segment {
	switch s {
	case "*":
		return glob.Segment{glob.Star, ""}
	case "**":
		return glob.Segment{glob.StarStar, ""}
	case "?":
		return glob.Segment{glob.Question, ""}
	default:
		throw(fmt.Errorf("bad wildcard: %q", s))
		panic("unreachable")
	}
}

func stringToSegments(s string) []glob.Segment {
	segs := []glob.Segment{}
	for i := 0; i < len(s); {
		j := i
		for ; j < len(s) && s[j] != '/'; j++ {
		}
		if j > i {
			segs = append(segs, glob.Segment{glob.Literal, s[i:j]})
		}
		if j < len(s) {
			for ; j < len(s) && s[j] == '/'; j++ {
			}
			segs = append(segs,
				glob.Segment{glob.Slash, ""})
			i = j
		} else {
			break
		}
	}
	return segs
}

func doGlob(gp GlobPattern) []Value {
	names := glob.Pattern(gp).Glob()
	vs := make([]Value, len(names))
	for i, name := range names {
		vs[i] = String(name)
	}
	return vs
}