feat: allow for configurable line length limit in the usage messages

clap.gen.go

@@ -7,6 +7,7 @@ import (
 	"fmt"
 	"io"
 	"os"
+	"reflect"
 	"strconv"
 )
 
@@ -93,19 +94,42 @@ func (v *clapString) Set(s string) error {
 	return nil
 }
 
+type clapInt[T int | int8 | int16 | int32 | int64] struct{ v *T }
+
+func clapNewInt[T int | int8 | int16 | int32 | int64](p *T) clapInt[T] { return clapInt[T]{p} }
+
+func (v clapInt[T]) String() string { return strconv.FormatInt(int64(*v.v), 10) }
+
+func (v clapInt[T]) Set(s string) error {
+	u64, err := strconv.ParseInt(s, 0, reflect.TypeFor[T]().Bits())
+	if err != nil {
+		return numError(err)
+	}
+	*v.v = T(u64)
+	return nil
+}
+
+func numError(err error) error {
+	if ne, ok := err.(*strconv.NumError); ok {
+		return ne.Err
+	}
+	return err
+}
+
 func (*goclap) UsageHelp() string {
 	return `goclap - Pre-build tool to generate command line argument parsing code from Go comments
 
 usage:
    goclap [options]
 
 options:
-   -type  <arg>     The root command struct name
-   -srcdir  <arg>   Directory of source files to parse (default ".")
-   -with-version    Include goclap's version info in the generated code
-   -out  <arg>      Output file path (default "./clap.gen.go")
-   -version         Print version info and exit
-   -h               Show this help message`
+   -type  <arg>             The root command struct name
+   -srcdir  <arg>           Directory of source files to parse (default ".")
+   -with-version            Include goclap's version info in the generated code
+   -out  <arg>              Output file path (default "./clap.gen.go")
+   -usg-text-width  <arg>   Max width for lines of text in the usage message
+   -version                 Print version info and exit
+   -h                       Show this help message`
 }
 
 func (c *goclap) Parse(args []string) {
@@ -116,6 +140,7 @@ func (c *goclap) Parse(args []string) {
 			{name: "srcdir", value: clapNewString(&c.srcDir)},
 			{name: "with-version", value: clapNewBool(&c.withVersion)},
 			{name: "out", value: clapNewString(&c.outFilePath)},
+			{name: "usg-text-width", value: clapNewInt(&c.usgTextWidth)},
 			{name: "version", value: clapNewBool(&c.version)},
 		},
 	}

generate.go

@@ -9,8 +9,6 @@ import (
 	"unicode"
 )
 
-const maxUsgLineLen = 90
-
 var (
 	//go:embed tmpls/base-unexported.go.tmpl
 	baseUnexportedTmplText string
@@ -22,8 +20,8 @@ var (
 	parseFnTmplText string
 )
 
-func generate(incVersion bool, pkgName string, root *command) ([]byte, error) {
-	g, err := newGenerator()
+func generate(incVersion bool, pkgName string, usgTextWidth int, root *command) ([]byte, error) {
+	g, err := newGenerator(usgTextWidth)
 	if err != nil {
 		return nil, fmt.Errorf("initializing generator: %w", err)
 	}
@@ -37,16 +35,15 @@ func generate(incVersion bool, pkgName string, root *command) ([]byte, error) {
 }
 
 type generator struct {
-	buf         bytes.Buffer
-	usgFnTmpl   *template.Template
-	parseFnTmpl *template.Template
+	buf          bytes.Buffer
+	usgTextWidth int
+	usgFnTmpl    *template.Template
+	parseFnTmpl  *template.Template
 }
 
-func newGenerator() (generator, error) {
-	usgFnTmpl, err := template.New("usagefunc").Parse(usgFnTmplText)
-	if err != nil {
-		return generator{}, fmt.Errorf("parsing template: %w", err)
-	}
+func newGenerator(usgTextWidth int) (generator, error) {
+	usgFnTmpl := template.Must(template.New("usagefunc").Parse(usgFnTmplText))
+
 	parseFuncs := template.FuncMap{
 		"add": func(a, b int) int { return a + b },
 	}
@@ -55,8 +52,9 @@ func newGenerator() (generator, error) {
 		return generator{}, fmt.Errorf("parsing template: %w", err)
 	}
 	return generator{
-		usgFnTmpl:   usgFnTmpl,
-		parseFnTmpl: parseFnTmpl,
+		usgTextWidth: usgTextWidth,
+		usgFnTmpl:    usgFnTmpl,
+		parseFnTmpl:  parseFnTmpl,
 	}, nil
 }
 
@@ -183,7 +181,7 @@ func (g *generator) genCmdUsageFunc(c *command) error {
 			if v, ok := o.data.getConfig("env"); ok {
 				desc += " [$" + v + "]"
 			}
-			optUsgs[i] = paddedNameAndArg + wrapBlurb(desc, len(paddedNameAndArg), maxUsgLineLen)
+			optUsgs[i] = paddedNameAndArg + wrapBlurb(desc, len(paddedNameAndArg), g.usgTextWidth)
 		}
 	}
 
@@ -201,7 +199,7 @@ func (g *generator) genCmdUsageFunc(c *command) error {
 			if v, ok := a.data.getConfig("env"); ok {
 				desc += " [$" + v + "]"
 			}
-			argUsgs[i] = paddedName + wrapBlurb(desc, len(paddedName), maxUsgLineLen)
+			argUsgs[i] = paddedName + wrapBlurb(desc, len(paddedName), g.usgTextWidth)
 		}
 	}
 
@@ -215,7 +213,7 @@ func (g *generator) genCmdUsageFunc(c *command) error {
 		}
 		for i, sc := range c.Subcmds {
 			paddedName := fmt.Sprintf("   %-*s   ", subcmdNameColWidth, sc.UsgName())
-			subcmdUsgs[i] = paddedName + wrapBlurb(sc.Data.Blurb, len(paddedName), maxUsgLineLen)
+			subcmdUsgs[i] = paddedName + wrapBlurb(sc.Data.Blurb, len(paddedName), g.usgTextWidth)
 		}
 	}
 
@@ -287,7 +285,8 @@ func (c *command) Overview() string {
 	paras := c.Data.overview
 	var s strings.Builder
 	for i := range paras {
-		s.WriteString(wrapText(paras[i], 3, maxUsgLineLen))
+		s.WriteString("   ")
+		s.WriteString(paras[i])
 		if i != len(paras)-1 {
 			s.WriteString("\n\n")
 		}

main.go

@@ -28,6 +28,10 @@ type goclap struct {
 	//
 	// clap:opt out
 	outFilePath string
+	// Max width for lines of text in the usage message.
+	//
+	// clap:opt usg-text-width
+	usgTextWidth int
 	// Print version info and exit.
 	//
 	// clap:opt version
@@ -143,6 +147,10 @@ func (c *command) UsgName() string {
 }
 
 func gen(c *goclap) error {
+	if c.usgTextWidth == 0 {
+		c.usgTextWidth = 90
+	}
+
 	rootCmdTypeName := c.rootCmdType
 	if rootCmdTypeName == "" {
 		fmt.Fprintf(os.Stderr, "no root command type provided\n")
@@ -155,7 +163,7 @@ func gen(c *goclap) error {
 		return err
 	}
 
-	code, err := generate(c.withVersion, pkgName, &rootCmd)
+	code, err := generate(c.withVersion, pkgName, c.usgTextWidth, &rootCmd)
 	if err != nil {
 		return err
 	}