multi-regexp pretokenizer (#12325)

model/bytepairencoding.go

@@ -5,6 +5,7 @@ import (
 	"fmt"
 	"iter"
 	"log/slog"
+	"slices"
 	"strings"
 
 	"github.com/dlclark/regexp2"
@@ -13,16 +14,28 @@ import (
 )
 
 type BytePairEncoding struct {
-	pre   *regexp2.Regexp
 	vocab   *Vocabulary
+	regexps []*regexp2.Regexp
 }
 
 var _ TextProcessor = (*BytePairEncoding)(nil)
 
-func NewBytePairEncoding(pre string, vocab *Vocabulary) BytePairEncoding {
+func NewBytePairEncoding(vocab *Vocabulary, pretokenizers ...string) BytePairEncoding {
+	if len(pretokenizers) == 0 {
+		// set default byte-level pretokenizer if none provided, e.g.
+		// https://github.com/huggingface/tokenizers/blob/main/tokenizers/src/pre_tokenizers/byte_level.rs#L44
+		pretokenizers = []string{`'s|'t|'re|'ve|'m|'ll|'d| ?\p{L}+| ?\p{N}+| ?[^\s\p{L}\p{N}]+|\s+(?!\S)|\s+`}
+	}
+
 	return BytePairEncoding{
-		pre:   regexp2.MustCompile(pre, regexp2.None),
 		vocab: vocab,
+		regexps: slices.Collect(func(yield func(*regexp2.Regexp) bool) {
+			for _, p := range pretokenizers {
+				if !yield(regexp2.MustCompile(p, regexp2.RE2)) {
+					return
+				}
+			}
+		}),
 	}
 }
 
@@ -35,13 +48,36 @@ func (bpe BytePairEncoding) Is(id int32, special Special) bool {
 }
 
 func (bpe *BytePairEncoding) split(s string) iter.Seq[string] {
-	return func(yield func(string) bool) {
+	parts := []string{s}
-		for m, _ := bpe.pre.FindStringMatch(s); m != nil; m, _ = bpe.pre.FindNextMatch(m) {
+	for _, re := range bpe.regexps {
+		parts = slices.Collect(func(yield func(string) bool) {
+			for _, part := range parts {
+				r := []rune(part)
+				var offset int
+				for m, _ := re.FindRunesMatch(r); m != nil; m, _ = re.FindNextMatch(m) {
+					if offset-m.Index != 0 {
+						if !yield(string(r[:m.Index])) {
+							return
+						}
+					}
+
 					if !yield(m.String()) {
-				break
+						return
+					}
+
+					offset = m.Index + m.Length
+				}
+
+				if offset < len(r) {
+					if !yield(string(r[offset:])) {
+						return
 					}
 				}
 			}
+		})
+	}
+
+	return slices.Values(parts)
 }
 
 // fragment is a string fragment and their corresponding token IDs

model/bytepairencoding_test.go

@@ -59,12 +59,12 @@ func llama(t testing.TB) BytePairEncoding {
 	}
 
 	return NewBytePairEncoding(
-		`(?i:'s|'t|'re|'ve|'m|'ll|'d)|[^\r\n\p{L}\p{N}]?\p{L}+|\p{N}{1,3}| ?[^\s\p{L}\p{N}]+[\r\n]*|\s*[\r\n]+|\s+(?!\S)|\s+`,
 		&Vocabulary{
 			Values: tokens,
 			Types:  types,
 			Merges: merges,
 		},
+		"(?i:'s|'t|'re|'ve|'m|'ll|'d)|[^\\r\\n\\p{L}\\p{N}]?\\p{L}+|\\p{N}{1,3}| ?[^\\s\\p{L}\\p{N}]+[\\r\\n]*|\\s*[\\r\\n]+|\\s+(?!\\S)|\\s+",
 	)
 }
 
@@ -282,3 +282,41 @@ func BenchmarkBytePairEncoding(b *testing.B) {
 		})
 	}
 }
+
+func TestSplit(t *testing.T) {
+	cases := []struct {
+		name string
+		patterns,
+		want []string
+	}{
+		{
+			name: "default",
+			want: []string{"Hello", ",", " WORLD", "!!", " How", "'s", " it", " going", "?", " 123", " 一二三"},
+		},
+		{
+			name: "unicode",
+			patterns: []string{
+				"\\p{N}{1,3}",
+				`[一-龥぀-ゟ゠-ヿ]+`,
+				"[!\"#$%&'()*+,\\-./:;<=>?@\\[\\\\\\]^_`{|}~][A-Za-z]+|[^\r\n\\p{L}\\p{P}\\p{S}]?[\\p{L}\\p{M}]+| ?[\\p{P}\\p{S}]+[\r\n]*|\\s*[\r\n]+|\\s+(?!\\S)|\\s+",
+			},
+			want: []string{"Hello", ",", " WORLD", "!!", " How", "'s", " it", " going", "?", " ", "123", " ", "一二三"},
+		},
+		{
+			name: "individual digits",
+			patterns: []string{
+				"(?i:'s|'t|'re|'ve|'m|'ll|'d)|[^\\r\\n\\p{L}\\p{N}]?\\p{L}+|\\p{N}| ?[^\\s\\p{L}\\p{N}]+[\\r\\n]*|\\s*[\\r\\n]+|\\s+(?!\\S)|\\s+",
+			},
+			want: []string{"Hello", ",", " WORLD", "!!", " How", "'s", " it", " going", "?", " ", "1", "2", "3", " 一二三"},
+		},
+	}
+
+	for _, tt := range cases {
+		t.Run(tt.name, func(t *testing.T) {
+			tokenizer := NewBytePairEncoding(nil, tt.patterns...)
+			if diff := cmp.Diff(tt.want, slices.Collect(tokenizer.split("Hello, WORLD!! How's it going? 123 一二三"))); diff != "" {
+				t.Errorf("no match (-theirs +ours):\n%s", diff)
+			}
+		})
+	}
+}

model/models/gptoss/model.go

@@ -227,17 +227,6 @@ func New(c fs.Config) (model.Model, error) {
 	m := Transformer{
 		TransformerBlocks: make([]TransformerBlock, c.Uint("block_count")),
 		BytePairEncoding: model.NewBytePairEncoding(
-			c.String("tokenizer.ggml.pretokenizer",
-				strings.Join([]string{
-					`[^\r\n\p{L}\p{N}]?[\p{Lu}\p{Lt}\p{Lm}\p{Lo}\p{M}]*[\p{Ll}\p{Lm}\p{Lo}\p{M}]+(?i:'s|'t|'re|'ve|'m|'ll|'d)?`,
-					`[^\r\n\p{L}\p{N}]?[\p{Lu}\p{Lt}\p{Lm}\p{Lo}\p{M}]+[\p{Ll}\p{Lm}\p{Lo}\p{M}]*(?i:'s|'t|'re|'ve|'m|'ll|'d)?`,
-					`\p{N}{1,3}`,
-					` ?[^\s\p{L}\p{N}]+[\r\n/]*`,
-					`\s*[\r\n]+`,
-					`\s+(?!\S)`,
-					`\s+`,
-				}, "|"),
-			),
 			&model.Vocabulary{
 				Values: c.Strings("tokenizer.ggml.tokens"),
 				Types:  c.Ints("tokenizer.ggml.token_type"),
@@ -250,6 +239,15 @@ func New(c fs.Config) (model.Model, error) {
 					c.Ints("tokenizer.ggml.eos_token_ids")...,
 				),
 			},
+			strings.Join([]string{
+				`[^\r\n\p{L}\p{N}]?[\p{Lu}\p{Lt}\p{Lm}\p{Lo}\p{M}]*[\p{Ll}\p{Lm}\p{Lo}\p{M}]+(?i:'s|'t|'re|'ve|'m|'ll|'d)?`,
+				`[^\r\n\p{L}\p{N}]?[\p{Lu}\p{Lt}\p{Lm}\p{Lo}\p{M}]+[\p{Ll}\p{Lm}\p{Lo}\p{M}]*(?i:'s|'t|'re|'ve|'m|'ll|'d)?`,
+				`\p{N}{1,3}`,
+				` ?[^\s\p{L}\p{N}]+[\r\n/]*`,
+				`\s*[\r\n]+`,
+				`\s+(?!\S)`,
+				`\s+`,
+			}, "|"),
 		),
 		Options: Options{
 			hiddenSize:            int(c.Uint("embedding_length")),

model/models/llama/model.go

@@ -54,10 +54,30 @@ func New(c fs.Config) (model.Model, error) {
 	}
 	switch c.String("tokenizer.ggml.model") {
 	case "gpt2":
-		processor = model.NewBytePairEncoding(
+		var pretokenizers []string
-			`(?i:'s|'t|'re|'ve|'m|'ll|'d)|[^\r\n\p{L}\p{N}]?\p{L}+|\p{N}{1,3}| ?[^\s\p{L}\p{N}]+[\r\n]*|\s*[\r\n]+|\s+(?!\S)|\s+`,
+		switch c.String("tokenizer.ggml.pre") {
-			&vocabulary,
+		case "default":
-		)
+			// no-op use the default bpe pretokenizer
+		case "qwen2":
+			pretokenizers = []string{
+				"(?i:'s|'t|'re|'ve|'m|'ll|'d)|[^\\r\\n\\p{L}\\p{N}]?\\p{L}+|\\p{N}| ?[^\\s\\p{L}\\p{N}]+[\\r\\n]*|\\s*[\\r\\n]+|\\s+(?!\\S)|\\s+",
+			}
+		case "refact":
+			pretokenizers = []string{
+				`\p{N}`,
+				`'s|'t|'re|'ve|'m|'ll|'d| ?\p{L}+| ?\p{N}+| ?[^\s\p{L}\p{N}]+|\s+(?!\S)|\s+`,
+			}
+		case "tekken":
+			pretokenizers = []string{
+				"[^\\r\\n\\p{L}\\p{N}]?[\\p{Lu}\\p{Lt}\\p{Lm}\\p{Lo}\\p{M}]*[\\p{Ll}\\p{Lm}\\p{Lo}\\p{M}]+|[^\\r\\n\\p{L}\\p{N}]?[\\p{Lu}\\p{Lt}\\p{Lm}\\p{Lo}\\p{M}]+[\\p{Ll}\\p{Lm}\\p{Lo}\\p{M}]*|\\p{N}| ?[^\\s\\p{L}\\p{N}]+[\\r\\n/]*|\\s*[\\r\\n]+|\\s+(?!\\S)|\\s+",
+			}
+		default:
+			// use a llama-style pretokenizer
+			pretokenizers = []string{
+				"(?i:'s|'t|'re|'ve|'m|'ll|'d)|[^\\r\\n\\p{L}\\p{N}]?\\p{L}+|\\p{N}{1,3}| ?[^\\s\\p{L}\\p{N}]+[\\r\\n]*|\\s*[\\r\\n]+|\\s+(?!\\S)|\\s+",
+			}
+		}
+		processor = model.NewBytePairEncoding(&vocabulary, pretokenizers...)
 	case "llama":
 		processor = model.NewSentencePiece(&vocabulary)
 	default:

model/models/llama4/model.go

@@ -34,8 +34,6 @@ func (p *Projector) Forward(ctx ml.Context, visionOutputs ml.Tensor) ml.Tensor {
 func New(c fs.Config) (model.Model, error) {
 	m := Model{
 		BytePairEncoding: model.NewBytePairEncoding(
-			c.String("tokenizer.ggml.pretokenizer",
-				`[^\r\n\p{L}\p{N}]?[\p{Lu}\p{Lt}\p{Lm}\p{Lo}\p{M}]*[\p{Ll}\p{Lm}\p{Lo}\p{M}]+(?i:'s|'t|'re|'ve|'m|'ll|'d)?|[^\r\n\p{L}\p{N}]?[\p{Lu}\p{Lt}\p{Lm}\p{Lo}\p{M}]+[\p{Ll}\p{Lm}\p{Lo}\p{M}]*(?i:'s|'t|'re|'ve|'m|'ll|'d)?|\p{N}{1,3}| ?[^\s\p{L}\p{N}]+[\r\n/]*|\s*[\r\n]+|\s+(?!\S)|\s+`),
 			&model.Vocabulary{
 				Values: c.Strings("tokenizer.ggml.tokens"),
 				Types:  c.Ints("tokenizer.ggml.token_type"),
@@ -48,6 +46,7 @@ func New(c fs.Config) (model.Model, error) {
 					c.Ints("tokenizer.ggml.eos_token_ids")...,
 				),
 			},
+			`[^\r\n\p{L}\p{N}]?[\p{Lu}\p{Lt}\p{Lm}\p{Lo}\p{M}]*[\p{Ll}\p{Lm}\p{Lo}\p{M}]+(?i:'s|'t|'re|'ve|'m|'ll|'d)?|[^\r\n\p{L}\p{N}]?[\p{Lu}\p{Lt}\p{Lm}\p{Lo}\p{M}]+[\p{Ll}\p{Lm}\p{Lo}\p{M}]*(?i:'s|'t|'re|'ve|'m|'ll|'d)?|\p{N}{1,3}| ?[^\s\p{L}\p{N}]+[\r\n/]*|\s*[\r\n]+|\s+(?!\S)|\s+`,
 		),
 		ImageProcessor: newImageProcessor(c),
 		VisionModel:    newVisionModel(c),

model/models/mistral3/model.go

@@ -33,7 +33,6 @@ var _ model.TextProcessor = (*Model)(nil)
 func New(c fs.Config) (model.Model, error) {
 	m := &Model{
 		BytePairEncoding: model.NewBytePairEncoding(
-			c.String("tokenizer.ggml.pretokenizer", `[^\r\n\p{L}\p{N}]?[\p{Lu}\p{Lt}\p{Lm}\p{Lo}\p{M}]*[\p{Ll}\p{Lm}\p{Lo}\p{M}]+|[^\r\n\p{L}\p{N}]?[\p{Lu}\p{Lt}\p{Lm}\p{Lo}\p{M}]+[\p{Ll}\p{Lm}\p{Lo}\p{M}]*|\p{N}| ?[^\s\p{L}\p{N}]+[\r\n/]*|\s*[\r\n]+|\s+(?!\S)|\s+`),
 			&model.Vocabulary{
 				Values: c.Strings("tokenizer.ggml.tokens"),
 				Types:  c.Ints("tokenizer.ggml.token_type"),
@@ -46,6 +45,7 @@ func New(c fs.Config) (model.Model, error) {
 					c.Ints("tokenizer.ggml.eos_token_ids")...,
 				),
 			},
+			`[^\r\n\p{L}\p{N}]?[\p{Lu}\p{Lt}\p{Lm}\p{Lo}\p{M}]*[\p{Ll}\p{Lm}\p{Lo}\p{M}]+|[^\r\n\p{L}\p{N}]?[\p{Lu}\p{Lt}\p{Lm}\p{Lo}\p{M}]+[\p{Ll}\p{Lm}\p{Lo}\p{M}]*|\p{N}| ?[^\s\p{L}\p{N}]+[\r\n/]*|\s*[\r\n]+|\s+(?!\S)|\s+`,
 		),
 		TextModel:           newTextModel(c),
 		VisionModel:         newVisionModel(c),

model/models/mllama/model.go

@@ -33,7 +33,6 @@ const (
 func New(c fs.Config) (model.Model, error) {
 	m := Model{
 		BytePairEncoding: model.NewBytePairEncoding(
-			c.String("tokenizer.ggml.pretokenizer", `(?i:'s|'t|'re|'ve|'m|'ll|'d)|[^\r\n\p{L}\p{N}]?\p{L}+|\p{N}{1,3}| ?[^\s\p{L}\p{N}]+[\r\n]*|\s*[\r\n]+|\s+(?!\S)|\s+`),
 			&model.Vocabulary{
 				Values: c.Strings("tokenizer.ggml.tokens"),
 				Types:  c.Ints("tokenizer.ggml.token_type"),
@@ -46,6 +45,7 @@ func New(c fs.Config) (model.Model, error) {
 					c.Ints("tokenizer.ggml.eos_token_ids")...,
 				),
 			},
+			`(?i:'s|'t|'re|'ve|'m|'ll|'d)|[^\r\n\p{L}\p{N}]?\p{L}+|\p{N}{1,3}| ?[^\s\p{L}\p{N}]+[\r\n]*|\s*[\r\n]+|\s+(?!\S)|\s+`,
 		),
 		ImageProcessor: newImageProcessor(c),
 		VisionModel:    newVisionModel(c),

model/models/qwen2/model.go

@@ -139,7 +139,6 @@ func New(c fs.Config) (model.Model, error) {
 	m := Model{
 		Layers: make([]DecoderLayer, c.Uint("block_count")),
 		BytePairEncoding: model.NewBytePairEncoding(
-			c.String("tokenizer.ggml.pretokenizer", `(?i:'s|'t|'re|'ve|'m|'ll|'d)|[^\r\n\p{L}\p{N}]?\p{L}+|\p{N}| ?[^\s\p{L}\p{N}]+[\r\n]*|\s*[\r\n]+|\s+(?!\S)|\s+`),
 			&model.Vocabulary{
 				Values: c.Strings("tokenizer.ggml.tokens"),
 				Types:  c.Ints("tokenizer.ggml.token_type"),
@@ -152,6 +151,7 @@ func New(c fs.Config) (model.Model, error) {
 					c.Ints("tokenizer.ggml.eos_token_ids")...,
 				),
 			},
+			`(?i:'s|'t|'re|'ve|'m|'ll|'d)|[^\r\n\p{L}\p{N}]?\p{L}+|\p{N}| ?[^\s\p{L}\p{N}]+[\r\n]*|\s*[\r\n]+|\s+(?!\S)|\s+`,
 		),
 		Options: Options{
 			hiddenSize: int(c.Uint("embedding_length")),

model/models/qwen25vl/model.go

@@ -29,7 +29,6 @@ var _ model.MultimodalProcessor = (*Model)(nil)
 func New(c fs.Config) (model.Model, error) {
 	m := &Model{
 		BytePairEncoding: model.NewBytePairEncoding(
-			c.String("tokenizer.ggml.pretokenizer", `(?i:'s|'t|'re|'ve|'m|'ll|'d)|[^\r\n\p{L}\p{N}]?\p{L}+|\p{N}| ?[^\s\p{L}\p{N}]+[\r\n]*|\s*[\r\n]+|\s+(?!\S)|\s+`),
 			&model.Vocabulary{
 				Values: c.Strings("tokenizer.ggml.tokens"),
 				Types:  c.Ints("tokenizer.ggml.token_type"),
@@ -42,6 +41,7 @@ func New(c fs.Config) (model.Model, error) {
 					c.Ints("tokenizer.ggml.eos_token_ids")...,
 				),
 			},
+			`(?i:'s|'t|'re|'ve|'m|'ll|'d)|[^\r\n\p{L}\p{N}]?\p{L}+|\p{N}| ?[^\s\p{L}\p{N}]+[\r\n]*|\s*[\r\n]+|\s+(?!\S)|\s+`,
 		),
 		TextModel:      NewTextModel(c),
 		VisionModel:    newVisionModel(c),

model/models/qwen3/embed.go

@@ -35,7 +35,6 @@ func newEmbed(c fs.Config) (model.Model, error) {
 	}
 	m := embedModel{
 		BytePairEncoding: model.NewBytePairEncoding(
-			`(?i:'s|'t|'re|'ve|'m|'ll|'d)|[^\r\n\p{L}\p{N}]?\p{L}+|\p{N}| ?[^\s\p{L}\p{N}]+[\r\n]*|\s*[\r\n]+|\s+(?!\S)|\s+`,
 			&model.Vocabulary{
 				Values: c.Strings("tokenizer.ggml.tokens"),
 				Types:  c.Ints("tokenizer.ggml.token_type"),
@@ -48,6 +47,7 @@ func newEmbed(c fs.Config) (model.Model, error) {
 					c.Ints("tokenizer.ggml.eos_token_ids")...,
 				),
 			},
+			`(?i:'s|'t|'re|'ve|'m|'ll|'d)|[^\r\n\p{L}\p{N}]?\p{L}+|\p{N}| ?[^\s\p{L}\p{N}]+[\r\n]*|\s*[\r\n]+|\s+(?!\S)|\s+`,
 		),
 		Model: &Model{
 			Layers: layers,

model/models/qwen3/model.go

@@ -200,7 +200,6 @@ func New(c fs.Config) (model.Model, error) {
 
 	m := Model{
 		BytePairEncoding: model.NewBytePairEncoding(
-			`(?i:'s|'t|'re|'ve|'m|'ll|'d)|[^\r\n\p{L}\p{N}]?\p{L}+|\p{N}| ?[^\s\p{L}\p{N}]+[\r\n]*|\s*[\r\n]+|\s+(?!\S)|\s+`,
 			&model.Vocabulary{
 				Values: c.Strings("tokenizer.ggml.tokens"),
 				Types:  c.Ints("tokenizer.ggml.token_type"),
@@ -213,6 +212,7 @@ func New(c fs.Config) (model.Model, error) {
 					c.Ints("tokenizer.ggml.eos_token_ids")...,
 				),
 			},
+			`(?i:'s|'t|'re|'ve|'m|'ll|'d)|[^\r\n\p{L}\p{N}]?\p{L}+|\p{N}| ?[^\s\p{L}\p{N}]+[\r\n]*|\s*[\r\n]+|\s+(?!\S)|\s+`,
 		),
 		Layers: layers,
 		Options: &Options{

sample/samplers_test.go

@@ -82,7 +82,6 @@ func modelHelper(t testing.TB) model.BytePairEncoding {
 	merges := make([]string, 0, 1)
 	// Only need vocab for Grammar Test
 	return model.NewBytePairEncoding(
-		``,
 		&model.Vocabulary{
 			Values: tokens,
 			Types:  make([]int32, len(vocab)),