note
	description: "[
		Access to command-line arguments. This class 
		may be used as ancestor by classes needing its facilities.
	]"
	library: "Free implementation of ELKS library"
	status: "See notice at end of class."
	legal: "See notice at end of class."
	date: "$Date: 2018-05-18 08:50:43 +0000 (Fri, 18 May 2018) $"
	revision: "$Revision: 101749 $"

class interface
	ARGUMENTS

create 
	default_create
			-- Process instances of classes with no creation clause.
			-- (Default: do nothing.)
			-- (from ANY)

feature -- Access

	argument (i: INTEGER_32): STRING_8
			-- i-th argument of command that started system execution
			-- (the command name if i = 0)
		require
			index_large_enough: i >= 0
			index_small_enough: i <= argument_count
		ensure
			instance_free: class
			argument_not_void: Result /= Void

	Argument_array: ARRAY [STRING_8]
			-- Array containing command name (position 0) and arguments
		ensure
			instance_free: class
			argument_array_not_void: Result /= Void
			argument_array_compare_objects: Result.object_comparison

	Command_line: STRING_8
			-- Total command line
		ensure
			instance_free: class
				Result.count >= Command_name.count

	Command_name: STRING_8
			-- Name of command that started system execution
		ensure
			instance_free: class
			definition: Result ~ argument (0)

	generating_type: TYPE [detachable ARGUMENTS]
			-- Type of current object
			-- (type of which it is a direct instance)
			-- (from ANY)
		ensure -- from ANY
			generating_type_not_void: Result /= Void

	generator: STRING_8
			-- Name of current object's generating class
			-- (base class of the type of which it is a direct instance)
			-- (from ANY)
		ensure -- from ANY
			generator_not_void: Result /= Void
			generator_not_empty: not Result.is_empty
	
feature -- Measurement

	argument_count: INTEGER_32
			-- Number of arguments given to command that started
			-- system execution (command name does not count)
		ensure
			instance_free: class
			argument_count_positive: Result >= 0
	
feature -- Comparison

	frozen deep_equal (a: detachable ANY; b: like arg #1): BOOLEAN
			-- Are a and b either both void
			-- or attached to isomorphic object structures?
			-- (from ANY)
		ensure -- from ANY
			instance_free: class
			shallow_implies_deep: standard_equal (a, b) implies Result
			both_or_none_void: (a = Void) implies (Result = (b = Void))
			same_type: (Result and (a /= Void)) implies (b /= Void and then a.same_type (b))
			symmetric: Result implies deep_equal (b, a)

	frozen equal (a: detachable ANY; b: like arg #1): BOOLEAN
			-- Are a and b either both void or attached
			-- to objects considered equal?
			-- (from ANY)
		ensure -- from ANY
			instance_free: class
			definition: Result = (a = Void and b = Void) or else ((a /= Void and b /= Void) and then a.is_equal (b))

	frozen is_deep_equal alias "≡≡≡" (other: ARGUMENTS): BOOLEAN
			-- Are Current and other attached to isomorphic object structures?
			-- (from ANY)
		require -- from ANY
			other_not_void: other /= Void
		ensure -- from ANY
			shallow_implies_deep: standard_is_equal (other) implies Result
			same_type: Result implies same_type (other)
			symmetric: Result implies other.is_deep_equal (Current)

	is_equal (other: ARGUMENTS): BOOLEAN
			-- Is other attached to an object considered
			-- equal to current object?
			-- (from ANY)
		require -- from ANY
			other_not_void: other /= Void
		ensure -- from ANY
			symmetric: Result implies other ~ Current
			consistent: standard_is_equal (other) implies Result

	frozen standard_equal (a: detachable ANY; b: like arg #1): BOOLEAN
			-- Are a and b either both void or attached to
			-- field-by-field identical objects of the same type?
			-- Always uses default object comparison criterion.
			-- (from ANY)
		ensure -- from ANY
			instance_free: class
			definition: Result = (a = Void and b = Void) or else ((a /= Void and b /= Void) and then a.standard_is_equal (b))

	frozen standard_is_equal alias "" (other: ARGUMENTS): BOOLEAN
			-- Is other attached to an object of the same type
			-- as current object, and field-by-field identical to it?
			-- (from ANY)
		require -- from ANY
			other_not_void: other /= Void
		ensure -- from ANY
			same_type: Result implies same_type (other)
			symmetric: Result implies other.standard_is_equal (Current)
	
feature -- Status report

	coalesced_character_option_value (o: CHARACTER_8): detachable STRING_8
			-- The value, if any, specified for character option o on
			-- the command line.
			-- Defined as follows (where 'X' is the current 'option_sign' and
			-- 'xx' is an arbitrary, possibly empty sequence of characters):
			--   val if command line includes an argument of the form Xxxoval
			--	   (this may be an empty string if argument is just Xxxo).
			--   Void otherwise.
		require
			o_non_null: o /= '%U'
		ensure
			instance_free: class

	coalesced_word_option_value (opt: STRING_8): detachable STRING_8
			-- The value, if any, specified for word option opt on the
			-- command line.
			-- Defined as follows (where X is the current Option_sign):
			--   val if command line includes an argument of the form Xoptval
			--	   (this may be an empty string if argument is just Xopt).
			--   Void otherwise.
		require
			opt_non_void: opt /= Void
			opt_meaningful: not opt.is_empty
		ensure
			instance_free: class

	conforms_to (other: ANY): BOOLEAN
			-- Does type of current object conform to type
			-- of other (as per Eiffel: The Language, chapter 13)?
			-- (from ANY)
		require -- from ANY
			other_not_void: other /= Void

	index_of_beginning_with_word_option (opt: STRING_8): INTEGER_32
			-- Does command line specify argument beginning with word
			-- option opt and, if so, at what position?
			-- If one of the arguments in list of space-separated arguments
			-- is Xoptxx, where X is the current Option_sign, 'xx'
			-- is arbitrary, possibly empty sequence of characters,
			-- then index of this argument in list;
			-- else 0.
		require
			opt_non_void: opt /= Void
			opt_meaningful: not opt.is_empty
		ensure
			instance_free: class

	index_of_character_option (o: CHARACTER_8): INTEGER_32
			-- Does command line specify character option o and, if so,
			-- at what position?
			-- If one of the space-separated arguments is of the form Xxxoyy,
			-- where X is the current Option_sign, xx and yy
			-- are arbitrary, possibly empty sequences of characters,
			-- then index of this argument in list of arguments;
			-- else 0.
		require
			o_non_null: o /= '%U'
		ensure
			instance_free: class

	index_of_word_option (opt: STRING_8): INTEGER_32
			-- Does command line specify word option opt and, if so,
			-- at what position?
			-- If one of the arguments in list of space-separated arguments
			-- is Xopt, where X is the current Option_sign,
			-- then index of this argument in list;
			-- else 0.
		require
			opt_non_void: opt /= Void
			opt_meaningful: not opt.is_empty
		ensure
			instance_free: class

	Option_sign: CHARACTER_8_REF
			-- The character used to signal options on the command line.
			-- This can be '%U' if no sign is necessary for the argument
			-- to be an option
			-- Default is '-'
		ensure
			instance_free: class

	same_type (other: ANY): BOOLEAN
			-- Is type of current object identical to type of other?
			-- (from ANY)
		require -- from ANY
			other_not_void: other /= Void
		ensure -- from ANY
			definition: Result = (conforms_to (other) and other.conforms_to (Current))

	separate_character_option_value (o: CHARACTER_8): detachable STRING_8
			-- The value, if any, specified after character option o on
			-- the command line.
			-- This is one of the following (where X is the current
			-- Option_sign, xx and 'yy' are arbitrary, possibly empty
			-- sequences of characters):
			--   val if command line includes two consecutive arguments
			--	   of the form Xxxoyy and val respectively.
			--   Empty string if command line includes argument Xxxoyy, which is
			--	   either last argument or followed by argument starting with X.
			--   Void if there is no argument of the form Xxxoyy.
		require
			o_non_null: o /= '%U'
		ensure
			instance_free: class

	separate_word_option_value (opt: STRING_8): detachable STRING_8
			-- The value, if any, specified after word option opt on the
			-- command line.
			-- This is one of the following (where X is the current Option_sign):
			--   val if command line includes two consecutive arguments
			--	   of the form Xopt and val respectively.
			--   Empty string if command line includes argument Xopt, which is
			--	   either last argument or followed by argument starting with X.
			--   Void if no Xopt argument.
		require
			opt_non_void: opt /= Void
			opt_meaningful: not opt.is_empty
		ensure
			instance_free: class
	
feature -- Status setting

	set_option_sign (c: CHARACTER_8)
			-- Make c the option sign.
			-- Use'%U' if no sign is necessary for the argument to
			-- be an option
		ensure
			instance_free: class
	
feature -- Duplication

	copy (other: ARGUMENTS)
			-- Update current object using fields of object attached
			-- to other, so as to yield equal objects.
			-- (from ANY)
		require -- from ANY
			other_not_void: other /= Void
			type_identity: same_type (other)
		ensure -- from ANY
			is_equal: Current ~ other

	frozen deep_copy (other: ARGUMENTS)
			-- Effect equivalent to that of:
			--		copy (other . deep_twin)
			-- (from ANY)
		require -- from ANY
			other_not_void: other /= Void
		ensure -- from ANY
			deep_equal: deep_equal (Current, other)

	frozen deep_twin: ARGUMENTS
			-- New object structure recursively duplicated from Current.
			-- (from ANY)
		ensure -- from ANY
			deep_twin_not_void: Result /= Void
			deep_equal: deep_equal (Current, Result)

	frozen standard_copy (other: ARGUMENTS)
			-- Copy every field of other onto corresponding field
			-- of current object.
			-- (from ANY)
		require -- from ANY
			other_not_void: other /= Void
			type_identity: same_type (other)
		ensure -- from ANY
			is_standard_equal: standard_is_equal (other)

	frozen standard_twin: ARGUMENTS
			-- New object field-by-field identical to other.
			-- Always uses default copying semantics.
			-- (from ANY)
		ensure -- from ANY
			standard_twin_not_void: Result /= Void
			equal: standard_equal (Result, Current)

	frozen twin: ARGUMENTS
			-- New object equal to Current
			-- twin calls copy; to change copying/twinning semantics, redefine copy.
			-- (from ANY)
		ensure -- from ANY
			twin_not_void: Result /= Void
			is_equal: Result ~ Current
	
feature -- Basic operations

	frozen default: detachable ARGUMENTS
			-- Default value of object's type
			-- (from ANY)

	frozen default_pointer: POINTER
			-- Default value of type POINTER
			-- (Avoid the need to write p.default for
			-- some p of type POINTER.)
			-- (from ANY)
		ensure -- from ANY
			instance_free: class

	default_rescue
			-- Process exception for routines with no Rescue clause.
			-- (Default: do nothing.)
			-- (from ANY)

	frozen do_nothing
			-- Execute a null action.
			-- (from ANY)
		ensure -- from ANY
			instance_free: class
	
feature -- Access: Cursor

	new_cursor: ITERATION_CURSOR [STRING_8]
			-- Fresh cursor associated with current structure
		require -- from  ITERABLE
			True
		ensure -- from ITERABLE
			result_attached: Result /= Void
		ensure then
			instance_free: class
	
feature -- Output

	Io: STD_FILES
			-- Handle to standard file setup
			-- (from ANY)
		ensure -- from ANY
			instance_free: class
			io_not_void: Result /= Void

	out: STRING_8
			-- New string containing terse printable representation
			-- of current object
			-- (from ANY)
		ensure -- from ANY
			out_not_void: Result /= Void

	print (o: detachable ANY)
			-- Write terse external representation of o
			-- on standard output.
			-- (from ANY)
		ensure -- from ANY
			instance_free: class

	frozen tagged_out: STRING_8
			-- New string containing terse printable representation
			-- of current object
			-- (from ANY)
		ensure -- from ANY
			tagged_out_not_void: Result /= Void
	
feature -- Platform

	Operating_environment: OPERATING_ENVIRONMENT
			-- Objects available from the operating system
			-- (from ANY)
		ensure -- from ANY
			instance_free: class
			operating_environment_not_void: Result /= Void
	
invariant
	argument_array_consistent: Argument_array ~ internal_argument_array

		-- from ANY
	reflexive_equality: standard_is_equal (Current)
	reflexive_conformance: conforms_to (Current)

note
	copyright: "Copyright (c) 1984-2018, Eiffel Software and others"
	license: "Eiffel Forum License v2 (see http://www.eiffel.com/licensing/forum.txt)"
	source: "[
		Eiffel Software
		5949 Hollister Ave., Goleta, CA 93117 USA
		Telephone 805-685-1006, Fax 805-685-6869
		Website http://www.eiffel.com
		Customer support http://support.eiffel.com
	]"

end -- class ARGUMENTS

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