new constructors

reader.go

@@ -14,7 +14,7 @@ type Reader struct {
 	pos *Position
 }
 
-func NewReader(r io.Reader) *Reader {
+func New(r io.Reader) *Reader {
 	return &Reader{
 		buf: ds.NewArrayStack[posRune](),
 		src: bufio.NewReader(r),
@@ -22,6 +22,10 @@ func NewReader(r io.Reader) *Reader {
 	}
 }
 
+func NewFromString(str string) *Reader {
+	return New(strings.NewReader(str))
+}
+
 func (r *Reader) psrn(rn rune) posRune {
 	return posRune{
 		Rune: rn,
@@ -58,6 +62,22 @@ func (r *Reader) PeekRune() (rune, error) {
 	return rn, nil
 }
 
+// String returns the next len runes in r as a string.
+// If an error occurs, both the already read string and the error will be returned
+func (r *Reader) String(len int) (string, error) {
+	str := ""
+
+	for i := 0; i < len; i++ {
+		rn, err := r.Rune()
+		if err != nil {
+			return str, err
+		}
+		str += string(rn)
+	}
+
+	return str, nil
+}
+
 // UnreadRune unreads the last rune.
 // The next read will include the unread rune.
 // It returns ErrNothingToUnread if there wasn't any read yet
@@ -92,16 +112,27 @@ func (r *Reader) UnreadString(str string) error {
 	return r.UnreadRune()
 }
 
-// StringWhile reads runes and calls f for each one.
+// UnreadRunes calls UnreadRune n times
-// It returns all runes as a string for which f returned true.
+func (r *Reader) UnreadRunes(n int) error {
-// It stops when f returns false or an error occured.
+	for i := 0; i < n; i++ {
-// The rune for which f returned false will not be unread.
+		err := r.UnreadRune()
-func (r *Reader) StringWhile(f func(rn rune) bool) (string, error) {
+		if err != nil {
+			return err
+		}
+	}
+	return nil
+}
+
+// StringWhile reads runes and calls all functions for each one.
+// It returns all runes as a string for which any function returned true.
+// It stops when all functions returned false or an error occured.
+// The rune for which that function returned false will not be unread.
+func (r *Reader) StringWhile(f ...RuneFunc) (string, error) {
 	s := new(strings.Builder)
 
 	var rn rune
 	var err error
-	for rn, err = r.Rune(); err == nil && f(rn); rn, err = r.Rune() {
+	for rn, err = r.Rune(); err == nil && findFirstTrue(rn, f); rn, err = r.Rune() {
 		s.WriteRune(rn)
 	}
 
@@ -109,8 +140,8 @@ func (r *Reader) StringWhile(f func(rn rune) bool) (string, error) {
 }
 
 // PeekStringWhile acts as StringWhile but does not advance reader position
-func (r *Reader) PeekStringWhile(f func(rn rune) bool) (string, error) {
+func (r *Reader) PeekStringWhile(f ...RuneFunc) (string, error) {
-	str, err := r.StringWhile(f)
+	str, err := r.StringWhile(f...)
 	if err != nil {
 		return "", err
 	}
@@ -122,14 +153,17 @@ func (r *Reader) PeekStringWhile(f func(rn rune) bool) (string, error) {
 	return str, nil
 }
 
-// StringUntil is a shorthand for r.StringWhile(func(rn rune) bool { return !f(rn) })
+// StringUntil reads runes and calls all functions for each one.
-func (r *Reader) StringUntil(f func(rn rune) bool) (string, error) {
+// It returns all runes as a string for which all functions returned true.
-	return r.StringWhile(func(rn rune) bool { return !f(rn) })
+// It stops when any function returns false or an error occured.
+// The rune for which that function returned false will not be unread.
+func (r *Reader) StringUntil(f ...RuneFunc) (string, error) {
+	return r.StringWhile(func(rn rune) bool { return !findFirstTrue(rn, f) })
 }
 
 // PeekStringUntil acts as StringUntil but does not advance reader position
-func (r *Reader) PeekStringUntil(f func(rn rune) bool) (string, error) {
+func (r *Reader) PeekStringUntil(f ...RuneFunc) (string, error) {
-	str, err := r.StringUntil(f)
+	str, err := r.StringUntil(f...)
 	if err != nil {
 		return "", err
 	}
@@ -141,6 +175,27 @@ func (r *Reader) PeekStringUntil(f func(rn rune) bool) (string, error) {
 	return str, nil
 }
 
+// SkipUntil acts as StringUntil but discards the string
+func (r *Reader) SkipUntil(f ...RuneFunc) error {
+	_, err := r.StringUntil(f...)
+	return err
+}
+
+// SkipWhile acts as StringWhile but discards the string
+func (r *Reader) SkipWhile(f ...RuneFunc) error {
+	_, err := r.StringWhile(f...)
+	return err
+}
+
+// ExpectRune returns true if any function returns true for the next rune read from r
+func (r *Reader) ExpectRune(f ...RuneFunc) (bool, error) {
+	rn, err := r.Rune()
+	if err != nil {
+		return false, err
+	}
+	return findFirstTrue(rn, f), nil
+}
+
 // Commit clears the internal buffer and therefore removes all data which were already read.
 // After calling Commit any unreads will return ErrNothingToUnread until another read occured.
 func (r *Reader) Commit() {

reader_test.go

@@ -7,7 +7,7 @@ import (
 )
 
 func TestPos(t *testing.T) {
-	r := NewReader(strings.NewReader("hello world\nsecond line"))
+	r := New(strings.NewReader("hello world\nsecond line"))
 
 	unread := false
 	for rn, err := r.Rune(); err == nil; rn, err = r.Rune() {
@@ -24,13 +24,13 @@ func TestPos(t *testing.T) {
 }
 
 func TestEOF(t *testing.T) {
-	r := NewReader(strings.NewReader("hello world\nasddsa"))
+	r := New(strings.NewReader("hello world\nasddsa"))
 
-	for line, err := r.StringUntil(isNewline); err == nil; line, err = r.StringUntil(isNewline) {
+	var line string
+	var err error
+	for line, err = r.StringUntil(IsNewLine); err == nil; line, err = r.StringUntil(IsNewLine) {
 		fmt.Println(line, err)
 	}
-}
 
-func isNewline(rn rune) bool {
+	fmt.Println(line, err)
-	return rn == '\n'
 }

runefunc.go

@@ -0,0 +1,52 @@
+package bufr
+
+import "git.milar.in/milarin/ds"
+
+type RuneFunc = func(rn rune) bool
+
+func IsNewLine(rn rune) bool {
+	return rn == '\n'
+}
+
+func IsSpace(rn rune) bool {
+	return rn == ' '
+}
+
+func IsWhitespace(rn rune) bool {
+	return IsSpace(rn) || IsNewLine(rn)
+}
+
+func And(f ...RuneFunc) RuneFunc {
+	return func(rn rune) bool {
+		return findFirstFalse(rn, f)
+	}
+}
+
+func Or(f ...RuneFunc) RuneFunc {
+	return func(rn rune) bool {
+		return findFirstTrue(rn, f)
+	}
+}
+
+func Not(f RuneFunc) RuneFunc {
+	return func(rn rune) bool {
+		return !f(rn)
+	}
+}
+
+func Is(rn rune) RuneFunc {
+	return func(r rune) bool {
+		return rn == r
+	}
+}
+
+func OneOf(runes string) RuneFunc {
+	m := ds.NewSet[rune]()
+	for _, rn := range runes {
+		m.Add(rn)
+	}
+
+	return func(r rune) bool {
+		return m.Has(r)
+	}
+}

utils.go

@@ -13,3 +13,21 @@ func prependString(str string, r io.Reader) *bufio.Reader {
 func prependRune(rn rune, r io.Reader) *bufio.Reader {
 	return prependString(string(rn), r)
 }
+
+func findFirstTrue(rn rune, functions []RuneFunc) bool {
+	for _, f := range functions {
+		if f(rn) {
+			return true
+		}
+	}
+	return false
+}
+
+func findFirstFalse(rn rune, functions []RuneFunc) bool {
+	for _, f := range functions {
+		if !f(rn) {
+			return false
+		}
+	}
+	return true
+}