mirror of
https://github.com/strongdm/comply
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100 lines
3.6 KiB
Go
100 lines
3.6 KiB
Go
/*
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package goptions implements a flexible parser for command line options.
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Key targets were the support for both long and short flag versions, mutually
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exclusive flags, and verbs. Flags and their corresponding variables are defined
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by the tags in a (possibly anonymous) struct.
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var options struct {
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Name string `goptions:"-n, --name"`
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Force bool `goptions:"-f, --force"`
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Verbosity int `goptions:"-v, --verbose"`
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}
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Short flags can be combined (e.g. `-nfv`). Long flags take their value after a
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separating space. The equals notation (`--long-flag=value`) is NOT supported
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right now.
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Every member of the struct which is supposed to catch a command line value
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has to have a "goptions" tag. The contains the short and long flag names for this
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member but can additionally specify any of these options below.
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obligatory - Flag must be specified. Otherwise an error will be returned
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when Parse() is called.
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description='...' - Set the description for this particular flag. Will be
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used by the HelpFunc.
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mutexgroup='...' - Add this flag to a MutexGroup. Only one flag of the
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ones sharing a MutexGroup can be set. Otherwise an error
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will be returned when Parse() is called. If one flag in a
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MutexGroup is `obligatory` one flag of the group must be
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specified. A flag can be in multiple MutexGroups at once.
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Depending on the type of the struct member, additional options might become available:
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Type: *os.File
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The given string is interpreted as a path to a file. If the string is "-"
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os.Stdin or os.Stdout will be used. os.Stdin will be returned, if the
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`rdonly` flag was set. os.Stdout will be returned, if `wronly` was set.
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Available options:
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Any combination of create, append, rdonly, wronly, rdwr,
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excl, sync, trunc and perm can be specified and correspond directly with
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the combination of the homonymous flags in the os package.
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Type: *net.TCPAddr
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The given string is interpreted as a tcp address. It is passed to
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net.ResolvTCPAddr() with "tcp" as the network type identifier.
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Type: *net/url.URL
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The given string is parsed by net/url.Parse()
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Type: time.Duration
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The given string is parsed by time.ParseDuration()
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If a member is a slice type, multiple definitions of the flags are possible. For each
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specification the underlying type will be used.
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var options struct {
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Servers []string `goptions:"-s, --server, description='Servers to connect to'"`
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}{}
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goptions also has support for verbs. Each verb accepts its own set of flags which
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take exactly the same tag format as global options. For an usage example of verbs
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see the PrintHelp() example.
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*/
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package goptions
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import (
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"os"
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"path/filepath"
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)
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const (
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VERSION = "2.5.11"
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)
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var (
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globalFlagSet *FlagSet
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)
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// ParseAndFail is a convenience function to parse os.Args[1:] and print
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// the help if an error occurs. This should cover 90% of this library's
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// applications.
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func ParseAndFail(v interface{}) {
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globalFlagSet = NewFlagSet(filepath.Base(os.Args[0]), v)
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globalFlagSet.ParseAndFail(os.Stderr, os.Args[1:])
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}
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// Parse parses the command-line flags from os.Args[1:].
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func Parse(v interface{}) error {
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globalFlagSet = NewFlagSet(filepath.Base(os.Args[0]), v)
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return globalFlagSet.Parse(os.Args[1:])
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}
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// PrintHelp renders the default help to os.Stderr.
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func PrintHelp() {
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if globalFlagSet == nil {
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panic("Must call Parse() before PrintHelp()")
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}
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globalFlagSet.PrintHelp(os.Stderr)
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}
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