From 07b98cb91243293e26564058a78f28b83aa81cd4 Mon Sep 17 00:00:00 2001
From: Eyal Posener <posener@gmail.com>
Date: Sat, 6 May 2017 19:08:47 +0300
Subject: [PATCH] Use pointers to predicates

---
 command.go             | 10 ++++------
 gocomplete/complete.go | 12 ++++++------
 gocomplete/tests.go    |  4 ++--
 predicate.go           | 34 ++++++++++++++++------------------
 run_test.go            |  6 +++---
 5 files changed, 31 insertions(+), 35 deletions(-)

diff --git a/command.go b/command.go
index 253f8e7..7bc0fc5 100644
--- a/command.go
+++ b/command.go
@@ -2,13 +2,13 @@ package complete
 
 type Commands map[string]Command
 
-type Flags map[string]Predicate
+type Flags map[string]*Predicate
 
 type Command struct {
 	Name  string
 	Sub   Commands
 	Flags Flags
-	Args  Predicate
+	Args  *Predicate
 }
 
 // options returns all available complete options for the given command
@@ -20,7 +20,7 @@ func (c *Command) options(args []string) (options []Option, only bool) {
 
 	// if prev has something that needs to follow it,
 	// it is the most relevant completion
-	if predicate, ok := c.Flags[last(args)]; ok && !predicate.ExpectsNothing {
+	if predicate, ok := c.Flags[last(args)]; ok && predicate != nil {
 		return predicate.predict(), true
 	}
 
@@ -41,9 +41,7 @@ func (c *Command) options(args []string) (options []Option, only bool) {
 	}
 
 	// add additional expected argument of the command
-	if !c.Args.ExpectsNothing {
-		options = append(options, c.Args.predict()...)
-	}
+	options = append(options, c.Args.predict()...)
 
 	return
 }
diff --git a/gocomplete/complete.go b/gocomplete/complete.go
index 7dc1694..60a9835 100644
--- a/gocomplete/complete.go
+++ b/gocomplete/complete.go
@@ -4,13 +4,13 @@ import (
 	"github.com/posener/complete"
 )
 
-var predictEllipsis = complete.Predicate{
-	Predictor: func() []complete.Option { return []complete.Option{complete.Arg("./...")} },
-}
+var (
+	predictEllipsis = complete.PredictSet("./...")
 
-var goFilesOrPackages = complete.PredictFiles("**.go").
-	Or(complete.PredictDirs("./")).
-	Or(predictEllipsis)
+	goFilesOrPackages = complete.PredictFiles("**.go").
+		Or(complete.PredictDirs("./")).
+		Or(predictEllipsis)
+)
 
 func main() {
 	build := complete.Command{
diff --git a/gocomplete/tests.go b/gocomplete/tests.go
index 388b7b7..0ab99ec 100644
--- a/gocomplete/tests.go
+++ b/gocomplete/tests.go
@@ -11,8 +11,8 @@ import (
 	"github.com/posener/complete"
 )
 
-func predictTest(testType string) complete.Predicate {
-	return complete.Predicate{
+func predictTest(testType string) *complete.Predicate {
+	return &complete.Predicate{
 		Predictor: func() []complete.Option {
 			tests := testNames(testType)
 			options := make([]complete.Option, len(tests))
diff --git a/predicate.go b/predicate.go
index bcf48b8..0740cfb 100644
--- a/predicate.go
+++ b/predicate.go
@@ -7,10 +7,6 @@ import (
 
 // Predicate determines what terms can follow a command or a flag
 type Predicate struct {
-	// ExpectsNothing determine if the predicate expects something after.
-	// flags/commands that do not expect any specific argument should
-	// leave it on false
-	ExpectsNothing bool
 	// Predictor is function that returns list of arguments that can
 	// come after the flag/command
 	Predictor func() []Option
@@ -18,27 +14,29 @@ type Predicate struct {
 
 // Or unions two predicate struct, so that the result predicate
 // returns the union of their predication
-func (p Predicate) Or(other Predicate) Predicate {
-	return Predicate{
-		ExpectsNothing: p.ExpectsNothing && other.ExpectsNothing,
-		Predictor:      func() []Option { return append(p.predict(), other.predict()...) },
+func (p *Predicate) Or(other *Predicate) *Predicate {
+	if p == nil || other == nil {
+		return nil
+	}
+	return &Predicate{
+		Predictor: func() []Option { return append(p.predict(), other.predict()...) },
 	}
 }
 
-func (p Predicate) predict() []Option {
-	if p.Predictor == nil {
+func (p *Predicate) predict() []Option {
+	if p == nil || p.Predictor == nil {
 		return nil
 	}
 	return p.Predictor()
 }
 
 var (
-	PredictNothing  = Predicate{ExpectsNothing: true}
-	PredictAnything = Predicate{}
+	PredictNothing  *Predicate = nil
+	PredictAnything            = &Predicate{}
 )
 
-func PredictSet(options ...string) Predicate {
-	return Predicate{
+func PredictSet(options ...string) *Predicate {
+	return &Predicate{
 		Predictor: func() []Option {
 			ret := make([]Option, len(options))
 			for i := range options {
@@ -49,12 +47,12 @@ func PredictSet(options ...string) Predicate {
 	}
 }
 
-func PredictFiles(pattern string) Predicate {
-	return Predicate{Predictor: glob(pattern)}
+func PredictFiles(pattern string) *Predicate {
+	return &Predicate{Predictor: glob(pattern)}
 }
 
-func PredictDirs(path string) Predicate {
-	return Predicate{Predictor: dirs(path)}
+func PredictDirs(path string) *Predicate {
+	return &Predicate{Predictor: dirs(path)}
 }
 
 func dirs(path string) func() []Option {
diff --git a/run_test.go b/run_test.go
index 0e18850..9800b6a 100644
--- a/run_test.go
+++ b/run_test.go
@@ -16,20 +16,20 @@ func TestCompleter_Complete(t *testing.T) {
 	c := Command{
 		Sub: map[string]Command{
 			"sub1": {
-				Flags: map[string]Predicate{
+				Flags: map[string]*Predicate{
 					"-flag1": PredictAnything,
 					"-flag2": PredictNothing,
 				},
 			},
 			"sub2": {
-				Flags: map[string]Predicate{
+				Flags: map[string]*Predicate{
 					"-flag2": PredictNothing,
 					"-flag3": PredictSet("opt1", "opt2", "opt12"),
 				},
 				Args: PredictDirs("./tests/").Or(PredictFiles("./tests/*.md")),
 			},
 		},
-		Flags: map[string]Predicate{
+		Flags: map[string]*Predicate{
 			"-h":       PredictNothing,
 			"-global1": PredictAnything,
 			"-o":       PredictFiles("./tests/*.txt"),