Added Bracket, Where, and Token (without tests)

TODO.txt

@@ -4,4 +4,6 @@ Rename Seq2 to Seq
 Document Seq
 Should MakeState be private now that there's Run?
 What's Megaparsec got that we ain't got?
-Add and benchmark naïve Seq
+Add and benchmark naïve Seq
+chainl
+whitespace handling

bytes/bytes.go

@@ -0,0 +1,16 @@
+package bytes
+
+import (
+	"git.codemonkeysoftware.net/b/gigaparsec"
+)
+
+func Token[Out, WSOut any](whitespace gigaparsec.Parser[byte, WSOut]) func(p gigaparsec.Parser[byte, Out]) gigaparsec.Parser[byte, Out] {
+	mappedWS := gigaparsec.Map(whitespace, func(WSOut) struct{} { return struct{}{} })
+	var ignoreWS gigaparsec.Parser[byte, struct{}] = func(s gigaparsec.State[byte]) (gigaparsec.Result[byte, struct{}], error) {
+		result, err := mappedWS(s)
+		return result.Consume(false), err
+	}
+	return func(p gigaparsec.Parser[byte, Out]) gigaparsec.Parser[byte, Out] {
+		return gigaparsec.Seq2(p, gigaparsec.Repeat(0, ignoreWS), func(val Out, _ []struct{}) Out { return val })
+	}
+}

bytes/regexp.go

@@ -69,6 +69,9 @@ func Regexp(pattern string) gigaparsec.Parser[byte, string] {
 			return gigaparsec.Result[byte, string]{}, fmt.Errorf("Regexp: reader error: %w", err)
 		}
 		if idx == nil {
+			if err == io.EOF {
+				return gigaparsec.Fail[byte, string](false, gigaparsec.MessageEnd(input.Pos())), nil
+			}
 			got := make([]byte, r.Count())
 			_, _, err = input.Read(got)
 			if err != nil {
@@ -80,7 +83,7 @@ func Regexp(pattern string) gigaparsec.Parser[byte, string] {
 		// when searching a RuneReader.
 		dst := make([]byte, idx[1]-idx[0])
 		n, _, err := input.Read(dst)
-		if err != nil {
+		if err != nil && (!errors.Is(err, io.EOF) || n < uint64(len(dst))) {
 			return gigaparsec.Result[byte, string]{}, fmt.Errorf("Regexp: unexpected error: %w", err)
 		}
 		next := input.At(input.Pos() + n)

bytes/regexp_test.go

@@ -61,6 +61,21 @@ func TestRegexp(t *testing.T) {
 		must.NoError(t, err)
 		test.StrContains(t, result.Message().Got(), "hella")
 	})
+	t.Run("succeeds on empty matches", func(t *testing.T) {
+		p := pbytes.Regexp(".*")
+		result, err := p(gigaparsec.MakeState(strings.NewReader("")))
+		succeeded, value, _ := result.Status()
+		must.NoError(t, err)
+		must.True(t, succeeded)
+		must.EqOp(t, "", value)
+	})
+	t.Run("fails without an error at EOF", func(t *testing.T) {
+		p := pbytes.Regexp("a")
+		result, err := p(gigaparsec.MakeState(strings.NewReader("")))
+		succeeded, _, _ := result.Status()
+		must.NoError(t, err)
+		must.False(t, succeeded)
+	})
 }
 
 func TestRuneReader(t *testing.T) {

gigaparsec.go

@@ -194,6 +194,17 @@ func (p Parser[In, Out]) Label(label string) Parser[In, Out] {
 	}
 }
 
+func (p Parser[In, Out]) Where(pred func(Out) bool) Parser[In, Out] {
+	return func(s State[In]) (Result[In, Out], error) {
+		result, err := p(s)
+		if result.success && !pred(result.value) {
+			result.success = false
+			result.message.got = "failed Where predicate"
+		}
+		return result, err
+	}
+}
+
 type ParseError Message
 
 func (pe ParseError) Error() string {
@@ -403,3 +414,16 @@ func Repeat[In, Out any](minCount int, p Parser[In, Out]) Parser[In, []Out] {
 		}
 	}
 }
+
+// Lazy delays creating a parser from p until the parser is called.
+// This is useful for preventing recursive function calls in the
+// definition of a recursive parser.
+func Lazy[In, Out any](p func() Parser[In, Out]) Parser[In, Out] {
+	return func(s State[In]) (Result[In, Out], error) {
+		return p()(s)
+	}
+}
+
+func Bracket[In, Out, LOut, ROut any](left Parser[In, LOut], p Parser[In, Out], right Parser[In, ROut]) Parser[In, Out] {
+	return Seq3(left, p, right, func(_ LOut, val Out, _ ROut) Out { return val })
+}

naive/naive.go

@@ -90,3 +90,176 @@ func Bind9[In, Out, T, T2, T3, T4, T5, T6, T7, T8, T9 any](
 ) gp.Parser[In, Out] {
 	return gp.Bind(gp.Bind(gp.Bind(gp.Bind(gp.Bind(gp.Bind(gp.Bind(gp.Bind(gp.Bind(p, f), f2), f3), f4), f5), f6), f7), f8), f9)
 }
+
+func Seq2[In, Out, T, T2 any](
+	p gp.Parser[In, T],
+	p2 gp.Parser[In, T2],
+	f func(T, T2) Out,
+) gp.Parser[In, Out] {
+	return gp.Bind(p, func(x T) gp.Parser[In, Out] {
+		return gp.Bind(p2, func(x2 T2) gp.Parser[In, Out] {
+			return gp.Return[In](f(x, x2))
+		})
+	})
+}
+func Seq3[In, Out, T, T2, T3 any](
+	p gp.Parser[In, T],
+	p2 gp.Parser[In, T2],
+	p3 gp.Parser[In, T3],
+	f func(T, T2, T3) Out,
+) gp.Parser[In, Out] {
+	return gp.Bind(p, func(x T) gp.Parser[In, Out] {
+		return gp.Bind(p2, func(x2 T2) gp.Parser[In, Out] {
+			return gp.Bind(p3, func(x3 T3) gp.Parser[In, Out] {
+				return gp.Return[In](f(x, x2, x3))
+			})
+		})
+	})
+}
+func Seq4[In, Out, T, T2, T3, T4 any](
+	p gp.Parser[In, T],
+	p2 gp.Parser[In, T2],
+	p3 gp.Parser[In, T3],
+	p4 gp.Parser[In, T4],
+	f func(T, T2, T3, T4) Out,
+) gp.Parser[In, Out] {
+	return gp.Bind(p, func(x T) gp.Parser[In, Out] {
+		return gp.Bind(p2, func(x2 T2) gp.Parser[In, Out] {
+			return gp.Bind(p3, func(x3 T3) gp.Parser[In, Out] {
+				return gp.Bind(p4, func(x4 T4) gp.Parser[In, Out] {
+					return gp.Return[In](f(x, x2, x3, x4))
+				})
+			})
+		})
+	})
+}
+func Seq5[In, Out, T, T2, T3, T4, T5 any](
+	p gp.Parser[In, T],
+	p2 gp.Parser[In, T2],
+	p3 gp.Parser[In, T3],
+	p4 gp.Parser[In, T4],
+	p5 gp.Parser[In, T5],
+	f func(T, T2, T3, T4, T5) Out,
+) gp.Parser[In, Out] {
+	return gp.Bind(p, func(x T) gp.Parser[In, Out] {
+		return gp.Bind(p2, func(x2 T2) gp.Parser[In, Out] {
+			return gp.Bind(p3, func(x3 T3) gp.Parser[In, Out] {
+				return gp.Bind(p4, func(x4 T4) gp.Parser[In, Out] {
+					return gp.Bind(p5, func(x5 T5) gp.Parser[In, Out] {
+						return gp.Return[In](f(x, x2, x3, x4, x5))
+					})
+				})
+			})
+		})
+	})
+}
+func Seq6[In, Out, T, T2, T3, T4, T5, T6 any](
+	p gp.Parser[In, T],
+	p2 gp.Parser[In, T2],
+	p3 gp.Parser[In, T3],
+	p4 gp.Parser[In, T4],
+	p5 gp.Parser[In, T5],
+	p6 gp.Parser[In, T6],
+	f func(T, T2, T3, T4, T5, T6) Out,
+) gp.Parser[In, Out] {
+	return gp.Bind(p, func(x T) gp.Parser[In, Out] {
+		return gp.Bind(p2, func(x2 T2) gp.Parser[In, Out] {
+			return gp.Bind(p3, func(x3 T3) gp.Parser[In, Out] {
+				return gp.Bind(p4, func(x4 T4) gp.Parser[In, Out] {
+					return gp.Bind(p5, func(x5 T5) gp.Parser[In, Out] {
+						return gp.Bind(p6, func(x6 T6) gp.Parser[In, Out] {
+							return gp.Return[In](f(x, x2, x3, x4, x5, x6))
+						})
+					})
+				})
+			})
+		})
+	})
+}
+func Seq7[In, Out, T, T2, T3, T4, T5, T6, T7 any](
+	p gp.Parser[In, T],
+	p2 gp.Parser[In, T2],
+	p3 gp.Parser[In, T3],
+	p4 gp.Parser[In, T4],
+	p5 gp.Parser[In, T5],
+	p6 gp.Parser[In, T6],
+	p7 gp.Parser[In, T7],
+	f func(T, T2, T3, T4, T5, T6, T7) Out,
+) gp.Parser[In, Out] {
+	return gp.Bind(p, func(x T) gp.Parser[In, Out] {
+		return gp.Bind(p2, func(x2 T2) gp.Parser[In, Out] {
+			return gp.Bind(p3, func(x3 T3) gp.Parser[In, Out] {
+				return gp.Bind(p4, func(x4 T4) gp.Parser[In, Out] {
+					return gp.Bind(p5, func(x5 T5) gp.Parser[In, Out] {
+						return gp.Bind(p6, func(x6 T6) gp.Parser[In, Out] {
+							return gp.Bind(p7, func(x7 T7) gp.Parser[In, Out] {
+								return gp.Return[In](f(x, x2, x3, x4, x5, x6, x7))
+							})
+						})
+					})
+				})
+			})
+		})
+	})
+}
+func Seq8[In, Out, T, T2, T3, T4, T5, T6, T7, T8 any](
+	p gp.Parser[In, T],
+	p2 gp.Parser[In, T2],
+	p3 gp.Parser[In, T3],
+	p4 gp.Parser[In, T4],
+	p5 gp.Parser[In, T5],
+	p6 gp.Parser[In, T6],
+	p7 gp.Parser[In, T7],
+	p8 gp.Parser[In, T8],
+	f func(T, T2, T3, T4, T5, T6, T7, T8) Out,
+) gp.Parser[In, Out] {
+	return gp.Bind(p, func(x T) gp.Parser[In, Out] {
+		return gp.Bind(p2, func(x2 T2) gp.Parser[In, Out] {
+			return gp.Bind(p3, func(x3 T3) gp.Parser[In, Out] {
+				return gp.Bind(p4, func(x4 T4) gp.Parser[In, Out] {
+					return gp.Bind(p5, func(x5 T5) gp.Parser[In, Out] {
+						return gp.Bind(p6, func(x6 T6) gp.Parser[In, Out] {
+							return gp.Bind(p7, func(x7 T7) gp.Parser[In, Out] {
+								return gp.Bind(p8, func(x8 T8) gp.Parser[In, Out] {
+									return gp.Return[In](f(x, x2, x3, x4, x5, x6, x7, x8))
+								})
+							})
+						})
+					})
+				})
+			})
+		})
+	})
+}
+func Seq9[In, Out, T, T2, T3, T4, T5, T6, T7, T8, T9 any](
+	p gp.Parser[In, T],
+	p2 gp.Parser[In, T2],
+	p3 gp.Parser[In, T3],
+	p4 gp.Parser[In, T4],
+	p5 gp.Parser[In, T5],
+	p6 gp.Parser[In, T6],
+	p7 gp.Parser[In, T7],
+	p8 gp.Parser[In, T8],
+	p9 gp.Parser[In, T9],
+	f func(T, T2, T3, T4, T5, T6, T7, T8, T9) Out,
+) gp.Parser[In, Out] {
+	return gp.Bind(p, func(x T) gp.Parser[In, Out] {
+		return gp.Bind(p2, func(x2 T2) gp.Parser[In, Out] {
+			return gp.Bind(p3, func(x3 T3) gp.Parser[In, Out] {
+				return gp.Bind(p4, func(x4 T4) gp.Parser[In, Out] {
+					return gp.Bind(p5, func(x5 T5) gp.Parser[In, Out] {
+						return gp.Bind(p6, func(x6 T6) gp.Parser[In, Out] {
+							return gp.Bind(p7, func(x7 T7) gp.Parser[In, Out] {
+								return gp.Bind(p8, func(x8 T8) gp.Parser[In, Out] {
+									return gp.Bind(p9, func(x9 T9) gp.Parser[In, Out] {
+										return gp.Return[In](f(x, x2, x3, x4, x5, x6, x7, x8, x9))
+									})
+								})
+							})
+						})
+					})
+				})
+			})
+		})
+	})
+}

naive/naive_test.go

@@ -56,3 +56,53 @@ func BenchmarkBind9(b *testing.B) {
 		}
 	})
 }
+
+func BenchmarkSeq5(b *testing.B) {
+	type P = gigaparsec.Parser[byte, byte]
+	type Seq5T = func(P, P, P, P, P, func(byte, byte, byte, byte, byte) byte) P
+
+	zero := gigaparsec.Return[byte, byte](0)
+
+	f := func(a, b, c, d, e byte) byte {
+		return a + b + c + d + e
+	}
+	p := func(seq5 Seq5T) P {
+		return seq5(zero, zero, zero, zero, zero, f)
+	}
+	input := gigaparsec.SliceReaderAt[byte]{0}
+	b.Run("gigaparsec.Seq5", func(b *testing.B) {
+		for range b.N {
+			gigaparsec.Run(p(gigaparsec.Seq5), input)
+		}
+	})
+	b.Run("naive.Seq5", func(b *testing.B) {
+		for range b.N {
+			gigaparsec.Run(p(naive.Seq5), input)
+		}
+	})
+}
+
+func BenchmarkSeq9(b *testing.B) {
+	type P = gigaparsec.Parser[byte, byte]
+	type Seq9T = func(P, P, P, P, P, P, P, P, P, func(byte, byte, byte, byte, byte, byte, byte, byte, byte) byte) P
+
+	zero := gigaparsec.Return[byte, byte](0)
+
+	f := func(a, b, c, d, e, f, g, h, i byte) byte {
+		return a + b + c + d + e + f + g + h + i
+	}
+	p := func(seq9 Seq9T) P {
+		return seq9(zero, zero, zero, zero, zero, zero, zero, zero, zero, f)
+	}
+	input := gigaparsec.SliceReaderAt[byte]{0}
+	b.Run("gigaparsec.Seq9", func(b *testing.B) {
+		for range b.N {
+			gigaparsec.Run(p(gigaparsec.Seq9), input)
+		}
+	})
+	b.Run("naive.Seq9", func(b *testing.B) {
+		for range b.N {
+			gigaparsec.Run(p(naive.Seq9), input)
+		}
+	})
+}

parser_test.go

@@ -210,3 +210,11 @@ func TestRepeat(t *testing.T) {
 		test.False(t, succeeded)
 	})
 }
+
+func TestBracket(t *testing.T) {
+	Todo(t)
+}
+
+func TestWhere(t *testing.T) {
+	Todo(t)
+}