Generate Bind

internal/bindgen/bind.go.tmpl

@@ -0,0 +1,35 @@
+{{define "fparams" -}}
+{{with $max := .}}{{range .Count}}	f{{.}} func(T{{.}}) Parser[In, {{if eq . $max}}Out{{else}}T{{.Next}}{{end}}],
+{{end}}{{end}}{{end -}}
+
+{{define "func" -}}
+func Bind{{.}}[In, Out{{range .Count}}, T{{.}}{{end}} any](
+	p Parser[In, T],
+{{template "fparams" .}}) Parser[In, Out] {
+	return func(s State[In]) (Result[In, Out], error) {
+		var anyConsumed bool
+		var failed bool
+		var msg Message
+		var next = s
+{{range .Next.Count}}
+		r{{.}}, err := {{if eq . 1}}p(next){{else}}f{{.Prev}}(val{{.Prev}})(next){{end}}
+		if err != nil {
+			return Result[In, Out]{}, err
+		}
+		anyConsumed = anyConsumed || r{{.}}.Consumed()
+		failed, _, msg = r{{.}}.Failed()
+		if failed {
+			return Fail[In, Out](anyConsumed, msg), nil
+		}
+		_, _, val{{.}}, next, _ := r{{.}}.Succeeded()
+{{end}}
+		return Succeed(anyConsumed, val{{.Next}}, next, MessageOK(s.Pos())), nil
+	}
+}{{end -}}
+
+// GENERATED FILE. DO NOT EDIT.
+
+package {{.Package}}
+{{range .Count}}
+{{template "func" .}}
+{{end}}

internal/bindgen/bindgen.go

@@ -0,0 +1,110 @@
+package main
+
+import (
+	_ "embed"
+	"errors"
+	"flag"
+	"fmt"
+	"os"
+	"strconv"
+	"text/template"
+)
+
+//go:embed bind.go.tmpl
+var bind string
+
+var tmpl *template.Template
+
+func main() {
+	err := run()
+	if err != nil {
+		fmt.Fprint(os.Stderr, err)
+		os.Exit(1)
+	}
+}
+
+func run() error {
+	outputPath := flag.String("output", "", "output file path")
+	maxBindLen := flag.Int("max", 0, "max bind length")
+	pkg := flag.String("pkg", "", "output package")
+	flag.Parse()
+
+	if *outputPath == "" {
+		return errors.New("output required")
+	}
+	if *maxBindLen == 0 {
+		return errors.New("maxbind required")
+	}
+	if *pkg == "" {
+		return errors.New("pkg required")
+	}
+
+	tmpl = template.New("")
+	_, err := tmpl.New("bind").Parse(bind)
+	if err != nil {
+		return fmt.Errorf("failed to parse bind: %w", err)
+	}
+
+	f, err := os.OpenFile(*outputPath, os.O_RDWR|os.O_CREATE|os.O_TRUNC, 0777)
+	if err != nil {
+		return err
+	}
+	defer f.Close()
+
+	data := File{
+		Package: *pkg,
+		Counter: Counter(*maxBindLen),
+	}
+	return tmpl.ExecuteTemplate(f, "bind", data)
+}
+
+type File struct {
+	Package string
+	Counter
+}
+
+// func (f File) Funcs() []Func {
+// 	counters := f.Max.Count()
+// 	funcs := make([]Func, len(counters))
+// 	for i, counter := range counters {
+// 		funcs[i] = Func{
+// 			Max:    f.Max,
+// 			Length: counter,
+// 		}
+// 	}
+// 	return funcs
+// }
+
+type Func struct {
+	Max    Counter
+	Length Counter
+}
+
+type Counter int
+
+func (c Counter) String() string {
+	if c == 1 {
+		return ""
+	}
+	return strconv.Itoa(int(c))
+}
+
+func (c Counter) Int() int {
+	return int(c)
+}
+
+func (c Counter) Next() Counter {
+	return c + 1
+}
+
+func (c Counter) Prev() Counter {
+	return c - 1
+}
+
+func (c Counter) Count() []Counter {
+	a := make([]Counter, c)
+	for i := range a {
+		a[i] = Counter(i + 1)
+	}
+	return a
+}