indexing
	description: "[
		Access to command-line arguments. This class 
		may be used as ancestor by classes needing its facilities.
	]"
	library: "Free implementation of ELKS library"
	copyright: "Copyright (c) 1986-2008, Eiffel Software and others"
	license: "Eiffel Forum License v2 (see forum.txt)"
	date: "$Date: 2008-05-23 17:24:07 -0700 (Fri, 23 May 2008) $"
	revision: "$Revision: 170 $"

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
			argument_not_void: Result /= Void

	argument_array: ARRAY [STRING_8]
			-- Array containing command name (position 0) and arguments
		ensure
			argument_array_not_void: Result /= Void

	command_line: STRING_8
			-- Total command line
		ensure
			Result.count >= command_name.count

	command_name: STRING_8
			-- Name of command that started system execution
		ensure
			definition: Result.is_equal (argument (0))

	generating_type: STRING_8
			-- Name of current object's generating type
			-- (type of which it is a direct instance)
			-- (from ANY)
		ensure -- from ANY
			generating_type_not_void: Result /= Void
			generating_type_not_empty: not Result.is_empty

	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
			argument_count_positive: Result >= 0
	
feature -- Comparison

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

	frozen equal (some: ?ANY; other: like arg #1): BOOLEAN
			-- Are `some' and `other' either both void or attached
			-- to objects considered equal?
			-- (from ANY)
		ensure -- from ANY
			definition: Result = (some = Void and other = Void) or else ((some /= Void and other /= Void) and then some.is_equal (other))

	frozen is_deep_equal (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.is_equal (Current)
			consistent: standard_is_equal (other) implies Result

	frozen standard_equal (some: ?ANY; other: like arg #1): BOOLEAN
			-- Are `some' and `other' 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
			definition: Result = (some = Void and other = Void) or else ((some /= Void and other /= Void) and then some.standard_is_equal (other))

	frozen standard_is_equal (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): ?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'

	coalesced_word_option_value (opt: STRING_8): ?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

	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

	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'

	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

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

	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): ?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'

	separate_word_option_value (opt: STRING_8): ?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
	
feature -- Status setting

	set_option_sign (c: CHARACTER_8)
			-- Make `c' the option sign.
			-- Use'%U' if no sign is necesary for the argument to
			-- be an option
	
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: is_equal (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/twining semantics, redefine copy.
			-- (from ANY)
		ensure -- from ANY
			twin_not_void: Result /= Void
			is_equal: Result.is_equal (Current)
	
feature -- Basic operations

	frozen default: ?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)

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

	frozen do_nothing
			-- Execute a null action.
			-- (from ANY)
	
feature -- Output

	io: STD_FILES
			-- Handle to standard file setup
			-- (from ANY)
		ensure -- from ANY
			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 (some: ?ANY)
			-- Write terse external representation of `some'
			-- on standard output.
			-- (from ANY)

	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
			operating_environment_not_void: Result /= Void
	
invariant
		-- from ANY
	reflexive_equality: standard_is_equal (Current)
	reflexive_conformance: conforms_to (Current)

end -- class ARGUMENTS