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|
package lexer
import (
"fmt"
"testing"
)
const (
NumberToken TokenType = iota
OpToken
IdentToken
)
func NumberState(l *Lexer) StateFunc {
l.AcceptRun("0123456789")
l.Emit(NumberToken)
if l.Peek() == '.' {
l.Next()
l.Emit(OpToken)
return IdentState
}
return nil
}
func IdentState(l *Lexer) StateFunc {
r := l.Next()
for (r >= 'a' && r <= 'z') || r == '_' {
r = l.Next()
}
l.Backup()
l.Emit(IdentToken)
return WhitespaceState
}
func NewlineState(l *Lexer) StateFunc {
l.AcceptRun("0123456789")
l.Emit(NumberToken)
l.SkipWhitespace()
l.Ignore()
l.AcceptRun("0123456789")
l.Emit(NumberToken)
l.SkipWhitespace()
return nil
}
func WhitespaceState(l *Lexer) StateFunc {
r := l.Next()
if r == EOFRune {
return nil
}
if r != ' ' && r != '\t' && r != '\n' && r != '\r' {
l.Error(fmt.Sprintf("unexpected token %q", r))
return nil
}
l.Accept(" \t\n\r")
l.Ignore()
return NumberState
}
func TestMovingThroughString(t *testing.T) {
l := New("123", nil)
run := []struct {
s string
r rune
}{
{"1", '1'},
{"12", '2'},
{"123", '3'},
{"123", EOFRune},
}
for _, test := range run {
r := l.Next()
if r != test.r {
t.Fatalf("Expected %q but got %q", test.r, r)
}
if l.Current() != test.s {
t.Fatalf("Expected %q but got %q", test.s, l.Current())
}
}
}
func TestNumbers(t *testing.T) {
l := New("123", NumberState)
l.Start()
tok, done := l.NextToken()
if done {
t.Fatal("Expected a token but lexer finished")
}
if tok.Type != NumberToken {
t.Fatalf("Expected a %v but got %v", NumberToken, tok.Type)
}
if tok.Value != "123" {
t.Fatalf("Expected %q but got %q", "123", tok.Value)
}
s := "[0] 123"
if tok.String() != s {
t.Fatalf("Expected %q but got %q", s, tok.String())
}
tok, done = l.NextToken()
if !done {
t.Fatal("Expected done but it wasn't.")
}
if tok != nil {
t.Fatalf("Expected a nil token but got %v", *tok)
}
}
func TestNewlines(t *testing.T) {
src := `123
456
789`
l := New(src, NewlineState)
l.Start()
tok, done := l.NextToken()
if done {
t.Fatal("Expected done, but it wasn't.")
}
if tok.Type != NumberToken {
t.Fatalf("Expected a number token but got %v", *tok)
}
if tok.Value != "123" {
t.Fatalf("Expected 123 but got %q", tok.Value)
}
if tok.Line != 1 {
t.Fatalf("Expected line 1 but got %d", tok.Line)
}
tok, done = l.NextToken()
if done {
t.Fatal("Expected not done, but it was.")
}
if tok.Type != NumberToken {
t.Fatalf("Expected a number token but got %v", *tok)
}
if tok.Value != "456" {
t.Fatalf("Expected 456 but got %q", tok.Value)
}
if tok.Line != 2 {
t.Fatalf("Expected line 2 but got %d", tok.Line)
}
}
func TestBackup(t *testing.T) {
l := New("1", nil)
r := l.Next()
if r != '1' {
t.Fatalf("Expected %q but got %q", '1', r)
}
if l.Current() != "1" {
t.Fatalf("Expected %q but got %q", "1", l.Current())
}
l.Backup()
if l.Current() != "" {
t.Fatalf("Expected empty string but got %q", l.Current())
}
}
func TestWhitespace(t *testing.T) {
l := New(" 1", NumberState)
l.Start()
l.SkipWhitespace()
tok, done := l.NextToken()
if done {
t.Fatal("Expected token to be !done, but it was.")
}
if tok.Type != NumberToken {
t.Fatalf("Expected number token but got %v", *tok)
}
}
func TestMultipleTokens(t *testing.T) {
cases := []struct {
tokType TokenType
val string
}{
{NumberToken, "123"},
{OpToken, "."},
{IdentToken, "hello"},
{NumberToken, "675"},
{OpToken, "."},
{IdentToken, "world"},
}
l := New("123.hello 675.world", NumberState)
l.Start()
for _, c := range cases {
tok, done := l.NextToken()
if done {
t.Fatal("Expected there to be more tokens but there weren't")
}
if c.tokType != tok.Type {
t.Fatalf("Expected token type %v but got %v", c.tokType, tok.Type)
}
if c.val != tok.Value {
t.Fatalf("Expected %q but got %q", c.val, tok.Value)
}
}
tok, done := l.NextToken()
if !done {
t.Fatal("Expected the lexer to be done but it wasn't.")
}
if tok != nil {
t.Fatalf("Did not expect a token, but got %v", *tok)
}
}
func TestError(t *testing.T) {
l := New("notaspace", WhitespaceState)
l.Start()
tok, done := l.NextToken()
if done {
t.Fatal("Expected token to be !done but it was.")
}
if tok.Type != ErrorToken {
t.Fatalf("Expected error token but got %v", *tok)
}
}
|
