argvreader

README

go-argvreader

import argvreader "github.com/Maki-Daisuke/go-argvreader"

Package argvreader makes it a bit less painful to write filter programs in Go especially for Perl programmers.

Description

The argvreader.Reader behaves just like Perl's <ARGV>, that reads lines from one file after another if file list is given in command line arguments, reads from STDIN otherwise. This may be useful to implement UNIX-style filter command, like gzip or grep.

Example

    import argvreader "github.com/Maki-Daisuke/go-argvreader"

    func main(){
      r := argvreader.New()
      b := bufio.NewReader(r)
      for{
        line, err := b.ReadString('\n')
        if err != nil {
          if err == io.EOF {
            break
          }
          panic(err)
        }
        do_something(line)
      }
    }

Then, in your command line:

$ ./main foo bar baz

This reads lines from foo, bar and baz one after another. If no argument is given:

$ ./main

This reads lines from STDIN instead.

You can pass file list manually, of course:

    import flags "github.com/jessevdk/go-flags"

    var opts struct { ... }

    args, err := flags.ParseArgs(&opts, args)
    r := argvreader.NewReader(args)

Usage

type Reader

type Reader interface {
	io.Reader
	CurrentFileName() string
}

Reader provides functionality just like Perl's ARGV file-handle and $ARGV variable.

CurrnetFileName returns a file name that is currently open and being read. It returns "-" if the Reader is reading from STDIN.

func New

func New() Reader

New is just shorthand of NewReader(os.Args[1:]).

func NewReader

func NewReader(args []string) Reader

NewReader creates Reader by manually passing file list. If the list is empty or nil, it returns a Reader reading from os.Stdin.

License

The Simplified BSD License (2-clause). See LICENSE file also.

Author

Daisuke (yet another) Maki

Documentation

Overview

Package argvreader makes it a bit less painful to write filter programs in Go especially for Perl programmers.

Description

The `argvreader.Reader` behaves just like Perl's `<ARGV>`, that reads lines from one file after another if file list is given in command line arguments, reads from STDIN otherwise. This may be useful to implement UNIX-style filter command, like gzip or grep.

Example

import argvreader "github.com/Maki-Daisuke/go-argvreader"

func main(){
  r := argvreader.New()
  b := bufio.NewReader(r)
  for{
    line, err := b.ReadString('\n')
    if err != nil {
      if err == io.EOF {
        break
      }
      panic(err)
    }
    do_something(line)
  }
}

Then, in your command line:

$ ./main foo bar baz

This reads lines from foo, bar and baz one after another. If no argument is given:

$ ./main

This reads lines from STDIN instead.

You can pass file list manually, of course:

import flags "github.com/jessevdk/go-flags"

var opts struct { ... }

args, err := flags.ParseArgs(&opts, args)
r := argvreader.NewReader(args)

Index

• type Reader
  • func New() Reader
  • func NewReader(args []string) Reader

Types

type Reader

type Reader interface {
	io.Reader
	Name() string
}

Reader provides functionality just like Perl's `ARGV` file-handle and `$ARGV` variable.

Name returns a file name that is currently open and being read. It returns "-" if the Reader is reading from STDIN.

func New

func New() Reader

New is just shorthand of `NewReader(os.Args[1:])`.

func NewReader

func NewReader(args []string) Reader

NewReader creates Reader by manually passing file list. If the list is empty or nil, it returns a Reader reading from os.Stdin.