class Toys::DSL::FlagGroup

DSL for a flag group definition block. Lets you create flags in a group.

These directives are available inside a block passed to {Toys::DSL::Tool#flag_group}, {Toys::DSL::Tool#all_required}, {Toys::DSL::Tool#at_most_one}, {Toys::DSL::Tool#at_least_one}, or {Toys::DSL::Tool#exactly_one}.

### Example

tool "login" do
  all_required do
    # The directives in here are defined by this class
    flag :username, "--username=VAL", desc: "Set username (required)"
    flag :password, "--password=VAL", desc: "Set password (required)"
  end
  # ...
end

Public Class Methods

new(tool_dsl, tool, flag_group) click to toggle source

@private

# File lib/toys/dsl/flag_group.rb, line 26
def initialize(tool_dsl, tool, flag_group)
  @tool_dsl = tool_dsl
  @tool = tool
  @flag_group = flag_group
end

Public Instance Methods

desc(desc) click to toggle source

Set the short description for the current flag group. The short description is displayed as the group title in online help.

The description is a {Toys::WrappableString}, which may be word-wrapped when displayed in a help screen. You may pass a {Toys::WrappableString} directly to this method, or you may pass any input that can be used to construct a wrappable string:

*  If you pass a String, its whitespace will be compacted (i.e. tabs,
   newlines, and multiple consecutive whitespace will be turned into a
   single space), and it will be word-wrapped on whitespace.
*  If you pass an Array of Strings, each string will be considered a
   literal word that cannot be broken, and wrapping will be done
   across the strings in the array. In this case, whitespace is not
   compacted.

### Examples

If you pass in a sentence as a simple string, it may be word wrapped when displayed:

desc "This sentence may be wrapped."

To specify a sentence that should never be word-wrapped, pass it as the sole element of a string array:

desc ["This sentence will not be wrapped."]

@param desc [String,Array<String>,Toys::WrappableString] @return [self]

# File lib/toys/dsl/flag_group.rb, line 239
def desc(desc)
  @flag_group.desc = desc
  self
end
flag(key, *flags, accept: nil, default: nil, handler: nil, complete_flags: nil, complete_values: nil, report_collisions: true, desc: nil, long_desc: nil, display_name: nil, &block) click to toggle source

Add a flag to the current group. Each flag must specify a key which the script may use to obtain the flag value from the context. You may then provide the flags themselves in OptionParser form.

If the given key is a symbol representing a valid method name, then a helper method is automatically added to retrieve the value. Otherwise, if the key is a string or does not represent a valid method name, the tool can retrieve the value by calling {Toys::Context#get}.

Attributes of the flag may be passed in as arguments to this method, or set in a block passed to this method. If you provide a block, you can use directives in {Toys::DSL::Flag} within the block.

### Flag syntax

The flags themselves should be provided in OptionParser form. Following are examples of valid syntax.

*  `-a` : A short boolean switch. When this appears as an argument,
   the value is set to `true`.
*  `--abc` : A long boolean switch. When this appears as an argument,
   the value is set to `true`.
*  `-aVAL` or `-a VAL` : A short flag that takes a required value.
   These two forms are treated identically. If this argument appears
   with a value attached (e.g. `-afoo`), the attached string (e.g.
   `"foo"`) is taken as the value. Otherwise, the following argument
   is taken as the value (e.g. for `-a foo`, the value is set to
   `"foo"`.) The following argument is treated as the value even if it
   looks like a flag (e.g. `-a -a` causes the string `"-a"` to be
   taken as the value.)
*  `-a[VAL]` : A short flag that takes an optional value. If this
   argument appears with a value attached (e.g. `-afoo`), the attached
   string (e.g. `"foo"`) is taken as the value. Otherwise, the value
   is set to `true`. The following argument is never interpreted as
   the value. (Compare with `-a [VAL]`.)
*  `-a [VAL]` : A short flag that takes an optional value. If this
   argument appears with a value attached (e.g. `-afoo`), the attached
   string (e.g. `"foo"`) is taken as the value. Otherwise, if the
   following argument does not look like a flag (i.e. it does not
   begin with a hyphen), it is taken as the value. (e.g. `-a foo`
   causes the string `"foo"` to be taken as the value.). If there is
   no following argument, or the following argument looks like a flag,
   the value is set to `true`. (Compare with `-a[VAL]`.)
*  `--abc=VAL` or `--abc VAL` : A long flag that takes a required
   value. These two forms are treated identically. If this argument
   appears with a value attached (e.g. `--abc=foo`), the attached
   string (e.g. `"foo"`) is taken as the value. Otherwise, the
   following argument is taken as the value (e.g. for `--abc foo`, the
   value is set to `"foo"`.) The following argument is treated as the
   value even if it looks like a flag (e.g. `--abc --def` causes the
   string `"--def"` to be taken as the value.)
*  `--abc[=VAL]` : A long flag that takes an optional value. If this
   argument appears with a value attached (e.g. `--abc=foo`), the
   attached string (e.g. `"foo"`) is taken as the value. Otherwise,
   the value is set to `true`. The following argument is never
   interpreted as the value. (Compare with `--abc [VAL]`.)
*  `--abc [VAL]` : A long flag that takes an optional value. If this
   argument appears with a value attached (e.g. `--abc=foo`), the
   attached string (e.g. `"foo"`) is taken as the value. Otherwise, if
   the following argument does not look like a flag (i.e. it does not
   begin with a hyphen), it is taken as the value. (e.g. `--abc foo`
   causes the string `"foo"` to be taken as the value.). If there is
   no following argument, or the following argument looks like a flag,
   the value is set to `true`. (Compare with `--abc=[VAL]`.)
*  `--[no-]abc` : A long boolean switch that can be turned either on
   or off. This effectively creates two flags, `--abc` which sets the
   value to `true`, and `--no-abc` which sets the falue to `false`.

### Default flag syntax

If no flag syntax strings are provided, a default syntax will be inferred based on the key and other options.

Specifically, if the key has one character, then that character will be chosen as a short flag. If the key has multiple characters, a long flag will be generated.

Furthermore, if a custom completion, a non-boolean acceptor, or a non-boolean default value is provided in the options, then the flag will be considered to take a value. Otherwise, it will be considered to be a boolean switch.

For example, the following pairs of flags are identical:

flag :a
flag :a, "-a"

flag :abc_def
flag :abc_def, "--abc-def"

flag :number, accept: Integer
flag :number, "--number=VAL", accept: Integer

### More examples

A flag that sets its value to the number of times it appears on the command line:

flag :verbose, "-v", "--verbose",
     default: 0, handler: ->(_val, count) { count + 1 }

An example using block form:

flag :shout do
  flags "-s", "--shout"
  default false
  desc "Say it louder"
  long_desc "This flag says it lowder.",
            "You might use this when people can't hear you.",
            "",
            "Example:",
            ["    toys say --shout hello"]
end

@param key [String,Symbol] The key to use to retrieve the value from

the execution context.

@param flags [String…] The flags in OptionParser format. @param accept [Object] An acceptor that validates and/or converts the

value. You may provide either the name of an acceptor you have
defined, or one of the default acceptors provided by OptionParser.
Optional. If not specified, accepts any value as a string.

@param default [Object] The default value. This is the value that will

be set in the context if this flag is not provided on the command
line. Defaults to `nil`.

@param handler [Proc,nil,:set,:push] An optional handler for

setting/updating the value. A handler is a proc taking two
arguments, the given value and the previous value, returning the
new value that should be set. You may also specify a predefined
named handler. The `:set` handler (the default) replaces the
previous value (effectively `-> (val, _prev) { val }`). The
`:push` handler expects the previous value to be an array and
pushes the given value onto it; it should be combined with setting
`default: []` and is intended for "multi-valued" flags.

@param complete_flags [Object] A specifier for shell tab completion

for flag names associated with this flag. By default, a
{Toys::Flag::DefaultCompletion} is used, which provides the flag's
names as completion candidates. To customize completion, set this
to the name of a previously defined completion, a hash of options
to pass to the constructor for {Toys::Flag::DefaultCompletion}, or
any other spec recognized by {Toys::Completion.create}.

@param complete_values [Object] A specifier for shell tab completion

for flag values associated with this flag. This is the empty
completion by default. To customize completion, set this to the
name of a previously defined completion, or any spec recognized by
{Toys::Completion.create}.

@param report_collisions [Boolean] Raise an exception if a flag is

requested that is already in use or marked as unusable. Default is
true.

@param desc [String,Array<String>,Toys::WrappableString] Short

description for the flag. See {Toys::DSL::Tool#desc} for a
description of the allowed formats. Defaults to the empty string.

@param long_desc [Array<String,Array<String>,Toys::WrappableString>]

Long description for the flag. See {Toys::DSL::Tool#long_desc} for
a description of the allowed formats. (But note that this param
takes an Array of description lines, rather than a series of
arguments.) Defaults to the empty array.

@param display_name [String] A display name for this flag, used in help

text and error messages.

@param block [Proc] Configures the flag. See {Toys::DSL::Flag} for the

directives that can be called in this block.

@return [self]

# File lib/toys/dsl/flag_group.rb, line 195
def flag(key, *flags,
         accept: nil, default: nil, handler: nil, complete_flags: nil, complete_values: nil,
         report_collisions: true, desc: nil, long_desc: nil, display_name: nil,
         &block)
  flag_dsl = DSL::Flag.new(flags, accept, default, handler, complete_flags, complete_values,
                           report_collisions, @flag_group, desc, long_desc, display_name)
  flag_dsl.instance_exec(flag_dsl, &block) if block
  flag_dsl._add_to(@tool, key)
  DSL::Internal.maybe_add_getter(@tool_dsl, key)
  self
end
long_desc(*long_desc) click to toggle source

Add to the long description for the current flag group. The long description is displayed with the flag group in online help. This directive may be given multiple times, and the results are cumulative.

A long description is a series of descriptions, which are generally displayed in a series of lines/paragraphs. Each individual description uses the form described in the {#desc} documentation, and may be word-wrapped when displayed. To insert a blank line, include an empty string as one of the descriptions.

### Example

long_desc "This initial paragraph might get word wrapped.",
          "This next paragraph is followed by a blank line.",
          "",
          ["This line will not be wrapped."],
          ["    This indent is preserved."]
long_desc "This line is appended to the description."

@param long_desc [String,Array<String>,Toys::WrappableString…] @return [self]

# File lib/toys/dsl/flag_group.rb, line 267
def long_desc(*long_desc)
  @flag_group.append_long_desc(long_desc)
  self
end