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
@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
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
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
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