installed flag

main.go

@@ -2,18 +2,30 @@ package main
 
 import (
 	"bufio"
+	"flag"
 	"fmt"
 	"os"
 	"strings"
 )
 
-const dataPathEnv = "NEXTWORD_DATA_PATH"
+// default env value for the data directory path.
+const envDataPath = "NEXTWORD_DATA_PATH"
+
+// flags
+var dataPath = flag.String("data", os.Getenv(envDataPath), "path to data directory")
+var maxCandidatesNum = flag.Int("candidates-num", 100, "max candidates num (positive int)")
+var helpFlag = flag.Bool("h", false, "show this message")
 
 func main() {
 	os.Exit(run())
 }
 
 func run() int {
+	if !parseArgs() {
+		flag.Usage()
+		return 1
+	}
+
 	if err := serve(); err != nil {
 		fmt.Fprintf(os.Stderr, "serve error: %v", err)
 		return 1
@@ -22,7 +34,7 @@ func run() int {
 }
 
 func serve() error {
-	sg := NewSuggester(os.Getenv(dataPathEnv), 100)
+	sg := NewSuggester(*dataPath, *maxCandidatesNum)
 
 	sc := bufio.NewScanner(os.Stdin)
 	for sc.Scan() {
@@ -39,3 +51,17 @@ func serve() error {
 
 	return nil
 }
+
+func parseArgs() bool {
+	flag.Parse()
+	if *helpFlag {
+		return false
+	}
+	if *maxCandidatesNum < 1 {
+		return false
+	}
+	if *dataPath == "" {
+		return false
+	}
+	return true
+}

suggester_test.go

@@ -7,7 +7,7 @@ import (
 	"testing"
 )
 
-var EnvDataPath = os.Getenv("NEXTWORD_DATA_PATH")
+var EnvDataPathTest = os.Getenv("NEXTWORD_DATA_PATH")
 
 func TestSuggester_Suggest(t *testing.T) {
 	tests := []struct {
@@ -87,7 +87,7 @@ func TestSuggester_Suggest(t *testing.T) {
 	}
 
 	for idx, test := range tests {
-		sg := NewSuggester(EnvDataPath, test.candidatesLen)
+		sg := NewSuggester(EnvDataPathTest, test.candidatesLen)
 
 		cand, err := sg.Suggest(test.query)
 		if err != nil {
@@ -103,7 +103,7 @@ func TestSuggester_Suggest(t *testing.T) {
 }
 
 func BenchmarkSuggester_Suggest(b *testing.B) {
-	sg := NewSuggester(EnvDataPath, 100)
+	sg := NewSuggester(EnvDataPathTest, 100)
 
 	for i := 0; i < b.N; i++ {
 		sg.Suggest("The quick brown fox ju")
@@ -195,17 +195,17 @@ func TestSuggester_SuggestNgram(t *testing.T) {
 			nil,
 		},
 		{
-			[]string{"0000000000"},
+			[]string{"0000000000 11111111 "},
 			nil,
 		},
 		{
-			[]string{"🤔"},
+			[]string{"🤔 🤗 "},
 			nil,
 		},
 	}
 
 	for idx, test := range tests {
-		sg := NewSuggester(EnvDataPath, 100)
+		sg := NewSuggester(EnvDataPathTest, 100)
 		cand, err := sg.suggestNgram(test.words)
 		if err != nil {
 			t.Errorf("[%d] unexpected error: %v", idx, err)
@@ -252,7 +252,7 @@ func TestSuggester_Suggest1gram(t *testing.T) {
 	}
 
 	for idx, test := range tests {
-		sg := NewSuggester(EnvDataPath, test.candidatesLen)
+		sg := NewSuggester(EnvDataPathTest, test.candidatesLen)
 
 		cand, err := sg.suggest1gram(test.prefix)
 		if !reflect.DeepEqual(test.err, err) {
@@ -361,27 +361,27 @@ func TestSuggester_BinSearch(t *testing.T) {
 		offset   int64
 	}{
 		{
-			filepath.Join(EnvDataPath, "1gram.txt"),
+			filepath.Join(EnvDataPathTest, "1gram.txt"),
 			"A",
 			0,
 		},
 		{
-			filepath.Join(EnvDataPath, "1gram.txt"),
+			filepath.Join(EnvDataPathTest, "1gram.txt"),
 			"zł",
 			11346418,
 		},
 		{
-			filepath.Join(EnvDataPath, "1gram.txt"),
+			filepath.Join(EnvDataPathTest, "1gram.txt"),
 			"Recu",
 			4901265,
 		},
 		{
-			filepath.Join(EnvDataPath, "1gram.txt"),
+			filepath.Join(EnvDataPathTest, "1gram.txt"),
 			"Latemaa",
 			3303588,
 		},
 		{
-			filepath.Join(EnvDataPath, "2gram-e.txt"),
+			filepath.Join(EnvDataPathTest, "2gram-e.txt"),
 			"ELSE",
 			24641,
 		},
@@ -422,17 +422,17 @@ func TestSuggester_FindHeadOfLine(t *testing.T) {
 		head     int64
 	}{
 		{
-			filepath.Join(EnvDataPath, "1gram.txt"),
+			filepath.Join(EnvDataPathTest, "1gram.txt"),
 			0,
 			0,
 		},
 		{
-			filepath.Join(EnvDataPath, "1gram.txt"),
+			filepath.Join(EnvDataPathTest, "1gram.txt"),
 			3,
 			2,
 		},
 		{
-			filepath.Join(EnvDataPath, "1gram.txt"),
+			filepath.Join(EnvDataPathTest, "1gram.txt"),
 			30749,
 			30734,
 		},
@@ -468,12 +468,12 @@ func TestSuggester_ReadLine(t *testing.T) {
 		line     string
 	}{
 		{
-			filepath.Join(EnvDataPath, "1gram.txt"),
+			filepath.Join(EnvDataPathTest, "1gram.txt"),
 			0,
 			"A",
 		},
 		{
-			filepath.Join(EnvDataPath, "2gram-e.txt"),
+			filepath.Join(EnvDataPathTest, "2gram-e.txt"),
 			13617,
 			"EDUCA\tTION",
 		},