booleanCount

README

Example Boolean Count

Overview

This example demos the counting of boolean flags. Each matching flag is removed as encountered and added to the final count. No errors are generated by the Args.Count method.

It demonstrates the following szargs functions:

// New creates a new Args object based in the arguments passed.  The first
// element of the arguments must be the program name.
func New(programDesc string, args []string) *Args

// Count returns the number of times the flag appears.
func (args *Args) Count(flag, desc string) int

// Done registers an error if there are any remaining arguments.
func (args *Args) Done()

// HasErr returns true if any errors have been encountered or registered.
func (args *Args) HasErr() bool

// Err returns any errors encountered or registered while parsing the
// arguments.
func (args *Args) Err() error

// Usage returns a usage message based on the parsed arguments.
func (args *Args) Usage() string

Contents

• Source (main.go)
  • Example: PASS: No Arguments
  • Example: PASS: Single Long Form
  • Example: PASS: Single Short Form
  • Example: PASS: Multiple Mixed Forms
  • Example: FAIL: Extra Unknown Argument

Source

The source used for this example. It simply defines a new szargs.Arg object, then defines a "count" flag which counts and removes the flags from the argument list. Finally the Done function is called to insure that no more arguments exist in the list.

cat ./main.go

// Package main implements a simple example of using szargs.
//
//nolint:forbidigo // OK to print to os.Stdout.
package main

import (
    "fmt"
    "os"

    "github.com/dancsecs/szargs"
)

func main() {
    args := szargs.New(
        "A simple utility to demo counting boolean flags.",
        os.Args,
    )

    howMany := args.Count(
        "[-c | --count ...]", // Short and long forms both repeatable.
        "How many times?",
    )

    args.Done() // All arguments should have consumed.

    if args.HasErr() {
        fmt.Fprintf(os.Stderr, "Error: %v\n\n%s\n", args.Err(), args.Usage())
    } else {
        fmt.Printf("How many: %d\n", howMany)
    }
}

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PASS: No Arguments

---

go run .

How many: 0

---

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PASS: Single Long Form

---

go run . --count

How many: 1

---

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PASS: Single Short Form

---

go run . -c

How many: 1

---

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PASS Multiple Mixed Forms

---

go run . --count -c -c

How many: 3

---

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FAIL: Extra Unknown Argument

The error is generated by the args.Done() statement causing both the error and a usage statement to be returned.

---

go run . --count extraUnknownArgument

Error: unexpected argument: [extraUnknownArgument]

booleanCount
A simple utility to demo counting boolean flags.

Usage: booleanCount [-c | --count ...]

[-c | --count ...]
How many times?

---

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Documentation

Overview

Package main implements a simple example of using szargs.