Introduced a system for shell segment priorities, which, if space is

limited, removes segments with lowest priority first.

main.go

@@ -13,6 +13,7 @@ type segment struct {
 	background          uint8
 	separator           string
 	separatorForeground uint8
+	priority            int
 }
 
 type args struct {
@@ -26,6 +27,7 @@ type args struct {
 	Theme            *string
 	Shell            *string
 	Modules          *string
+	Priority         *string
 	PrevError        *int
 }
 
@@ -42,7 +44,6 @@ func pathExists(path string) bool {
 }
 
 func getValidCwd() string {
-
 	cwd, exists := os.LookupEnv("PWD")
 	if !exists {
 		warn("Your current directory is invalid.")
@@ -113,11 +114,22 @@ func main() {
 			"The list of modules to load. Separate with ','\n"+
 				"    	(valid choices: cwd, docker, exit, git, hg, host, jobs, perms, root, ssh, time, user, venv)\n"+
 				"       "),
+		Priority: flag.String("priority",
+			"root,cwd,user,host,ssh,perms,git-branch,git-status,hg,jobs,exit",
+			"Segments sorted by priority, if not enough space exists, the least priorized segments are removed first. Separate with ','\n"+
+				"    	(valid choices: cwd, docker, exit, git-branch, git-status, hg, host, jobs, perms, root, ssh, time, user, venv)\n"+
+				"       "),
 		PrevError: flag.Int("error", 0,
 			"Exit code of previously executed command"),
 	}
 	flag.Parse()
-	powerline := NewPowerline(args, getValidCwd())
+	priorities := map[string]int{}
+	priorityList := strings.Split(*args.Priority, ",")
+	for idx, priority := range priorityList {
+		priorities[priority] = len(priorityList) - idx
+	}
+
+	powerline := NewPowerline(args, getValidCwd(), priorities)
 
 	for _, module := range strings.Split(*powerline.args.Modules, ",") {
 		elem, ok := modules[module]

powerline.go

@@ -4,6 +4,9 @@ import (
 	"bytes"
 	"fmt"
 	"golang.org/x/text/width"
+	"math"
+	"os"
+	"strconv"
 )
 
 type ShellInfo struct {
@@ -21,17 +24,19 @@ type powerline struct {
 	shellInfo       ShellInfo
 	reset           string
 	symbolTemplates Symbols
+	priorities      map[string]int
 	Segments        []segment
 }
 
-func NewPowerline(args args, cwd string) *powerline {
+func NewPowerline(args args, cwd string, priorities map[string]int) *powerline {
 	p := new(powerline)
 	p.args = args
 	p.cwd = cwd
 	p.theme = themes[*args.Theme]
 	p.shellInfo = shellInfos[*args.Shell]
 	p.reset = fmt.Sprintf(p.shellInfo.colorTemplate, "[0m")
 	p.symbolTemplates = symbolTemplates[*args.Mode]
+	p.priorities = priorities
 	p.Segments = make([]segment, 0)
 	return p
 }
@@ -52,21 +57,47 @@ func (p *powerline) bgColor(code uint8) string {
 	return p.color("48", code)
 }
 
-func (p *powerline) appendSegment(segment segment) {
+func (p *powerline) appendSegment(origin string, segment segment) {
 	if segment.separator == "" {
 		segment.separator = p.symbolTemplates.Separator
 	}
 	if segment.separatorForeground == 0 {
 		segment.separatorForeground = segment.background
 	}
+	priority, _ := p.priorities[origin]
+	segment.priority = priority
 	p.Segments = append(p.Segments, segment)
 }
 
 func (p *powerline) draw() string {
-	var buffer bytes.Buffer
-	for idx := range p.Segments {
-		segment := p.Segments[idx]
+	shellMaxLengthStr, _ := os.LookupEnv("COLUMNS")
+	shellMaxLength64, _ := strconv.ParseInt(shellMaxLengthStr, 0, 64)
+	shellMaxLength := int(shellMaxLength64)
+
+	shellActualLength := 0
+	if shellMaxLength > 0 {
+		for _, segment := range p.Segments {
+			shellActualLength += len(segment.content) + len(segment.separator)
+		}
+		for shellActualLength > shellMaxLength {
+			minPriority := math.MaxInt64
+			minPrioritySegmentId := -1
+			for idx, segment := range p.Segments {
+				if segment.priority < minPriority {
+					minPriority = segment.priority
+					minPrioritySegmentId = idx
+				}
+			}
+			if minPrioritySegmentId != -1 {
+				segment := p.Segments[minPrioritySegmentId]
+				p.Segments = append(p.Segments[:minPrioritySegmentId], p.Segments[minPrioritySegmentId+1:]...)
+				shellActualLength -= len(segment.content) + len(segment.separator)
+			}
+		}
+	}
 
+	var buffer bytes.Buffer
+	for idx, segment := range p.Segments {
 		var separatorBackground string
 		if idx >= len(p.Segments)-1 {
 			separatorBackground = p.reset

segment-cwd.go

@@ -84,7 +84,7 @@ func segmentCwd(p *powerline) {
 			cwd = "~" + cwd[len(home):]
 		}
 
-		p.appendSegment(segment{
+		p.appendSegment("cwd", segment{
 			content:    fmt.Sprintf(" %s ", cwd),
 			foreground: p.theme.CwdFg,
 			background: p.theme.PathBg,
@@ -128,7 +128,7 @@ func segmentCwd(p *powerline) {
 					segment.separatorForeground = p.theme.SeparatorFg
 				}
 
-				p.appendSegment(segment)
+				p.appendSegment("cwd", segment)
 			}
 		}
 	}

segment-docker.go

@@ -1,14 +1,14 @@
 package main
 
 import (
-	"os"
 	"fmt"
+	"os"
 )
 
 func segmentDocker(p *powerline) {
 	dockerMachineName, _ := os.LookupEnv("DOCKER_MACHINE_NAME")
 	if dockerMachineName != "" {
-		p.appendSegment(segment{
+		p.appendSegment("docker", segment{
 			content:    fmt.Sprintf(" %s ", dockerMachineName),
 			foreground: p.theme.DockerMachineFg,
 			background: p.theme.DockerMachineBg,

segment-exitcode.go

@@ -66,7 +66,7 @@ func getMeaningFromExitCode(exitCode int) string {
 func segmentExitCode(p *powerline) {
 	if *p.args.PrevError != 0 {
 		meaning := getMeaningFromExitCode(*p.args.PrevError)
-		p.appendSegment(segment{
+		p.appendSegment("exit", segment{
 			content:    fmt.Sprintf(" %s ", meaning),
 			foreground: p.theme.CmdFailedFg,
 			background: p.theme.CmdFailedBg,

segment-git.go

@@ -24,7 +24,7 @@ func (r repoStats) dirty() bool {
 
 func addRepoStatsSegment(p *powerline, nChanges int, symbol string, foreground uint8, background uint8) {
 	if nChanges > 0 {
-		p.appendSegment(segment{
+		p.appendSegment("git-status", segment{
 			content:    fmt.Sprintf(" %d%s ", nChanges, symbol),
 			foreground: foreground,
 			background: background,
@@ -152,7 +152,7 @@ func segmentGit(p *powerline) {
 			background = p.theme.RepoCleanBg
 		}
 
-		p.appendSegment(segment{
+		p.appendSegment("git-branch", segment{
 			content:    fmt.Sprintf(" %s ", branch),
 			foreground: foreground,
 			background: background,

segment-hg.go

@@ -60,7 +60,7 @@ func segmentHg(p *powerline) {
 			content = fmt.Sprintf(" %s ", branch)
 		}
 
-		p.appendSegment(segment{
+		p.appendSegment("hg", segment{
 			content:    content,
 			foreground: foreground,
 			background: background,

segment-hostname.go

@@ -41,7 +41,7 @@ func segmentHost(p *powerline) {
 		background = p.theme.HostnameBg
 	}
 
-	p.appendSegment(segment{
+	p.appendSegment("host", segment{
 		content:    hostPrompt,
 		foreground: foreground,
 		background: background,

segment-jobs.go

@@ -22,7 +22,7 @@ func segmentJobs(p *powerline) {
 	}
 
 	if nJobs > 0 {
-		p.appendSegment(segment{
+		p.appendSegment("jobs", segment{
 			content:    fmt.Sprintf(" %d ", nJobs),
 			foreground: p.theme.JobsFg,
 			background: p.theme.JobsBg,

segment-readonly.go

@@ -1,9 +1,9 @@
 package main
 
 import (
-	"os"
 	"fmt"
 	"golang.org/x/sys/unix"
+	"os"
 )
 
 func segmentPerms(p *powerline) {
@@ -12,7 +12,7 @@ func segmentPerms(p *powerline) {
 		cwd, _ = os.LookupEnv("PWD")
 	}
 	if unix.Access(cwd, unix.W_OK) != nil {
-		p.appendSegment(segment{
+		p.appendSegment("perms", segment{
 			content:    fmt.Sprintf(" %s ", p.symbolTemplates.Lock),
 			foreground: p.theme.ReadonlyFg,
 			background: p.theme.ReadonlyBg,

segment-root.go

@@ -10,7 +10,7 @@ func segmentRoot(p *powerline) {
 		background = p.theme.CmdFailedBg
 	}
 
-	p.appendSegment(segment{
+	p.appendSegment("root", segment{
 		content:    p.shellInfo.rootIndicator,
 		foreground: foreground,
 		background: background,

segment-ssh.go

@@ -1,14 +1,14 @@
 package main
 
 import (
-	"os"
 	"fmt"
+	"os"
 )
 
 func segmentSsh(p *powerline) {
 	sshClient, _ := os.LookupEnv("SSH_CLIENT")
 	if sshClient != "" {
-		p.appendSegment(segment{
+		p.appendSegment("ssh", segment{
 			content:    fmt.Sprintf(" %s ", p.symbolTemplates.Network),
 			foreground: p.theme.SshFg,
 			background: p.theme.SshBg,

segment-time.go

@@ -6,7 +6,7 @@ import (
 )
 
 func segmentTime(p *powerline) {
-	p.appendSegment(segment{
+	p.appendSegment("time", segment{
 		content:    fmt.Sprintf(" %s ", time.Now().Format("15:04:05")),
 		foreground: p.theme.TimeFg,
 		background: p.theme.TimeBg,

segment-username.go

@@ -23,7 +23,7 @@ func segmentUser(p *powerline) {
 		background = p.theme.UsernameBg
 	}
 
-	p.appendSegment(segment{
+	p.appendSegment("user", segment{
 		content:    userPrompt,
 		foreground: p.theme.UsernameFg,
 		background: background,

segment-virtualenv.go

@@ -1,8 +1,8 @@
 package main
 
 import (
-	"os"
 	"fmt"
+	"os"
 	"path"
 )
 
@@ -21,7 +21,7 @@ func segmentVirtualEnv(p *powerline) {
 		return
 	} else {
 		envName := path.Base(env)
-		p.appendSegment(segment{
+		p.appendSegment("venv", segment{
 			content:    fmt.Sprintf(" %s ", envName),
 			foreground: p.theme.VirtualEnvFg,
 			background: p.theme.VirtualEnvBg,