Support pinning directories using $le:loc-pinned.

This fixes #342.

edit/editor.go

@@ -35,14 +35,17 @@ type Editor struct {
 	evaler *eval.Evaler
 	cmdSeq int
 
-	prompt        eval.Variable
-	rprompt       eval.Variable
+	prompt            eval.Variable
+	rprompt           eval.Variable
+	rpromptPersistent eval.Variable
+
 	abbreviations map[string]string
 
-	locationHidden    eval.Variable
-	rpromptPersistent eval.Variable
-	beforeReadLine    eval.Variable
-	afterReadLine     eval.Variable
+	locationHidden eval.Variable
+	locationPinned eval.Variable
+
+	beforeReadLine eval.Variable
+	afterReadLine  eval.Variable
 
 	historyMutex sync.RWMutex
 
@@ -104,20 +107,22 @@ func NewEditor(file *os.File, sigs chan os.Signal, ev *eval.Evaler, st *store.St
 	prompt, rprompt := defaultPrompts()
 
 	ed := &Editor{
-		file:    file,
-		writer:  newWriter(file),
-		reader:  tty.NewReader(file),
-		sigs:    sigs,
-		store:   st,
-		evaler:  ev,
-		cmdSeq:  seq,
-		prompt:  eval.NewPtrVariableWithValidator(prompt, eval.ShouldBeFn),
-		rprompt: eval.NewPtrVariableWithValidator(rprompt, eval.ShouldBeFn),
+		file:   file,
+		writer: newWriter(file),
+		reader: tty.NewReader(file),
+		sigs:   sigs,
+		store:  st,
+		evaler: ev,
+		cmdSeq: seq,
+
+		prompt:            eval.NewPtrVariableWithValidator(prompt, eval.ShouldBeFn),
+		rprompt:           eval.NewPtrVariableWithValidator(rprompt, eval.ShouldBeFn),
+		rpromptPersistent: eval.NewPtrVariableWithValidator(eval.Bool(false), eval.ShouldBeBool),
 
 		abbreviations: make(map[string]string),
 
-		locationHidden:    eval.NewPtrVariableWithValidator(eval.NewList(), eval.ShouldBeList),
-		rpromptPersistent: eval.NewPtrVariableWithValidator(eval.Bool(false), eval.ShouldBeBool),
+		locationHidden: eval.NewPtrVariableWithValidator(eval.NewList(), eval.ShouldBeList),
+		locationPinned: eval.NewPtrVariableWithValidator(eval.NewList(), eval.ShouldBeList),
 
 		beforeReadLine: eval.NewPtrVariableWithValidator(eval.NewList(), eval.ShouldBeList),
 		afterReadLine:  eval.NewPtrVariableWithValidator(eval.NewList(), eval.ShouldBeList),

edit/location.go

@@ -3,6 +3,7 @@ package edit
 import (
 	"bytes"
 	"fmt"
+	"math"
 	"os"
 	"path/filepath"
 	"regexp"
@@ -16,6 +17,10 @@ import (
 
 // Location mode.
 
+// PinnedScore is a special value of Score in store.Dir to represent that the
+// directory is pinned.
+var PinnedScore = math.Inf(1)
+
 type location struct {
 	listing
 	home     string // The home directory; leave empty if unknown.
@@ -42,7 +47,13 @@ func (loc *location) Len() int {
 }
 
 func (loc *location) Show(i int) (string, styled) {
-	header := fmt.Sprintf("%.0f", loc.filtered[i].Score)
+	var header string
+	score := loc.filtered[i].Score
+	if score == PinnedScore {
+		header = "*"
+	} else {
+		header = fmt.Sprintf("%.0f", score)
+	}
 	return header, unstyled(showPath(loc.filtered[i].Path, loc.home))
 }
 
@@ -126,13 +137,28 @@ func startLocation(ed *Editor) {
 		ed.Notify("%v", ErrStoreOffline)
 		return
 	}
-	black := convertBlacklist(ed.locationHidden.Get().(eval.List))
+	black := convertListToSet(ed.locationHidden.Get().(eval.List))
 	dirs, err := ed.store.GetDirs(black)
 	if err != nil {
 		ed.Notify("store error: %v", err)
 		return
 	}
 
+	pinnedValue := ed.locationPinned.Get().(eval.List)
+	pinned := convertListToDirs(pinnedValue)
+	pinnedSet := convertListToSet(pinnedValue)
+
+	// TODO(xiaq): Optimize this by changing GetDirs to a callback API, and
+	// build dirs by first putting pinned directories and then appending those
+	// from store.
+	for _, d := range dirs {
+		_, inPinned := pinnedSet[d.Path]
+		if !inPinned {
+			pinned = append(pinned, d)
+		}
+	}
+	dirs = pinned
+
 	// Drop the error. When there is an error, home is "", which is used to
 	// signify "no home known" in location.
 	home, _ := util.GetHome("")
@@ -140,14 +166,28 @@ func startLocation(ed *Editor) {
 	ed.mode = ed.location
 }
 
-func convertBlacklist(li eval.List) map[string]struct{} {
-	black := make(map[string]struct{})
+// convertListToDirs converts a list of strings to []store.Dir. It uses the
+// special score of PinnedScore to signify that the directory is pinned.
+func convertListToDirs(li eval.List) []store.Dir {
+	pinned := make([]store.Dir, 0, li.Len())
 	// XXX(xiaq): silently drops non-string items.
 	li.Iterate(func(v eval.Value) bool {
 		if s, ok := v.(eval.String); ok {
-			black[string(s)] = struct{}{}
+			pinned = append(pinned, store.Dir{string(s), PinnedScore})
 		}
 		return true
 	})
-	return black
+	return pinned
+}
+
+func convertListToSet(li eval.List) map[string]struct{} {
+	set := make(map[string]struct{})
+	// XXX(xiaq): silently drops non-string items.
+	li.Iterate(func(v eval.Value) bool {
+		if s, ok := v.(eval.String); ok {
+			set[string(s)] = struct{}{}
+		}
+		return true
+	})
+	return set
 }

edit/location_test.go

@@ -8,6 +8,7 @@ import (
 
 var (
 	theLocation = newLocation([]store.Dir{
+		{"/pinned", PinnedScore},
 		{"/src/github.com/elves/elvish", 300},
 		{"/src/home/xyz", 233},
 		{"/home/dir", 100},
@@ -17,6 +18,7 @@ var (
 
 	locationFilterTests = []listingFilterTestCases{
 		{"", []shown{
+			{"*", unstyled("/pinned")},
 			{"300", unstyled("/src/github.com/elves/elvish")},
 			{"233", unstyled("/src/home/xyz")},
 			{"100", unstyled("~/dir")},       // home is abbreviated

edit/module.go

@@ -78,6 +78,7 @@ func makeModule(ed *Editor) eval.Namespace {
 
 	ns["abbr"] = eval.NewRoVariable(eval.MapStringString(ed.abbreviations))
 
+	ns["loc-pinned"] = ed.locationPinned
 	ns["loc-hidden"] = ed.locationHidden
 
 	ns["before-readline"] = ed.beforeReadLine