Programación en Ada/Unidades predefinidas/Standard
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[editar] Paquete Standard
La unidad Standard es un paquete especial que contiene las declaraciones de todos los tipos predefinidos tales como Integer o Boolean.
En términos de compilación es como si todas las unidades tuviesen escrito antes de nada:
withStandard;useStandard;
También posee un paquete anidado llamado ASCII, que contiene las constantes que definen los caracteres tales como CR (retorno de carro) o LF (avance de línea). Escribiendo use ASCII; se pueden referenciar simplemente como CR. Sin embargo el estándar de Ada 95 no nos recomienda usar el paquete ASCII (caracteres de 7 bits), porque éste queda obsoleto tras la definición del paquete Ada.Characters.Latin_1, que define el juego completo de caracteres ISO Latín 1 de 8 bits.
[editar] Especificación
La definición del paquete Standard según el manual de referencia de Ada:
package Standard is pragma Pure(Standard); type Boolean is (False, True); -- The predefined relational operators for this type are as follows: -- function "=" (Left, Right : Boolean'Base) return Boolean; -- function "/=" (Left, Right : Boolean'Base) return Boolean; -- function "<" (Left, Right : Boolean'Base) return Boolean; -- function "<=" (Left, Right : Boolean'Base) return Boolean; -- function ">" (Left, Right : Boolean'Base) return Boolean; -- function ">=" (Left, Right : Boolean'Base) return Boolean; -- The predefined logical operators and the predefined logical -- negation operator are as follows: -- function "and" (Left, Right : Boolean'Base) return Boolean; -- function "or" (Left, Right : Boolean'Base) return Boolean; -- function "xor" (Left, Right : Boolean'Base) return Boolean; -- function "not" (Right : Boolean'Base) return Boolean; -- The integer type root_integer is predefined. -- The corresponding universal type is universal_integer. type Integer is range ''implementation-defined''; subtype Natural is Integer range 0 .. Integer'Last; subtype Positive is Integer range 1 .. Integer'Last; -- The predefined operators for type Integer are as follows: -- function "=" (Left, Right : Integer'Base) return Boolean; -- function "/=" (Left, Right : Integer'Base) return Boolean; -- function "<" (Left, Right : Integer'Base) return Boolean; -- function "<=" (Left, Right : Integer'Base) return Boolean; -- function ">" (Left, Right : Integer'Base) return Boolean; -- function ">=" (Left, Right : Integer'Base) return Boolean; -- function "+" (Right : Integer'Base) return Integer'Base; -- function "-" (Right : Integer'Base) return Integer'Base; -- function "abs" (Right : Integer'Base) return Integer'Base; -- function "+" (Left, Right : Integer'Base) return Integer'Base; -- function "-" (Left, Right : Integer'Base) return Integer'Base; -- function "*" (Left, Right : Integer'Base) return Integer'Base; -- function "/" (Left, Right : Integer'Base) return Integer'Base; -- function "rem" (Left, Right : Integer'Base) return Integer'Base; -- function "mod" (Left, Right : Integer'Base) return Integer'Base; -- function "**" (Left : Integer'Base; Right : Natural) -- return Integer'Base; -- The specification of each operator for the type -- root_integer, or for any additional predefined integer -- type, is obtained by replacing Integer by the name of the type -- in the specification of the corresponding operator of the type -- Integer. The right operand of the exponentiation operator -- remains as subtype Natural. -- The floating point type root_real is predefined. -- The corresponding universal type is universal_real. type Float is digits ''implementation-defined''; -- The predefined operators for this type are as follows: -- function "=" (Left, Right : Float) return Boolean; -- function "/=" (Left, Right : Float) return Boolean; -- function "<" (Left, Right : Float) return Boolean; -- function "<=" (Left, Right : Float) return Boolean; -- function ">" (Left, Right : Float) return Boolean; -- function ">=" (Left, Right : Float) return Boolean; -- function "+" (Right : Float) return Float; -- function "-" (Right : Float) return Float; -- function "abs" (Right : Float) return Float; -- function "+" (Left, Right : Float) return Float; -- function "-" (Left, Right : Float) return Float; -- function "*" (Left, Right : Float) return Float; -- function "/" (Left, Right : Float) return Float; -- function "**" (Left : Float; Right : Integer'Base) return Float; -- The specification of each operator for the type root_real, or for -- any additional predefined floating point type, is obtained by -- replacing Float by the name of the type in the specification of the -- corresponding operator of the type Float. -- In addition, the following operators are predefined for the root -- numeric types: function "*" (Left : root_integer; Right : root_real) return root_real; function "*" (Left : root_real; Right : root_integer) return root_real; function "/" (Left : root_real; Right : root_integer) return root_real; -- The type universal_fixed is predefined. -- The only multiplying operators defined between -- fixed point types are function "*" (Left : universal_fixed; Right : universal_fixed) return universal_fixed; function "/" (Left : universal_fixed; Right : universal_fixed) return universal_fixed; -- The declaration of type Character is based on the standard ISO 8859-1 character set. -- There are no character literals corresponding to the positions for control characters. -- They are indicated in italics in this definition. See 3.5.2. type Character is (nul, soh, stx, etx, eot, enq, ack, bel, --0 (16#00#) .. 7 (16#07#) bs, ht, lf, vt, ff, cr, so, si, --8 (16#08#) .. 15 (16#0F#) dle, dc1, dc2, dc3, dc4, nak, syn, etb, --16 (16#10#) .. 23 (16#17#) can, em, sub, esc, fs, gs, rs, us, --24 (16#18#) .. 31 (16#1F#) ' ', '!', '"', '#', '$', '%', '&', ''', --32 (16#20#) .. 39 (16#27#) " '(', ')', '*', '+', ',', '-', '.', '/', --40 (16#28#) .. 47 (16#2F#) '0', '1', '2', '3', '4', '5', '6', '7', --48 (16#30#) .. 55 (16#37#) '8', '9', ':', ';', '<', '=', '>', '?', --56 (16#38#) .. 63 (16#3F#) '@', 'A', 'B', 'C', 'D', 'E', 'F', 'G', --64 (16#40#) .. 71 (16#47#) 'H', 'I', 'J', 'K', 'L', 'M', 'N', 'O', --72 (16#48#) .. 79 (16#4F#) 'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W', --80 (16#50#) .. 87 (16#57#) 'X', 'Y', 'Z', '[', '\', ']', '^', '_', --88 (16#58#) .. 95 (16#5F#) '`', 'a', 'b', 'c', 'd', 'e', 'f', 'g', --96 (16#60#) .. 103 (16#67#) 'h', 'i', 'j', 'k', 'l', 'm', 'n', 'o', --104 (16#68#) .. 111 (16#6F#) 'p', 'q', 'r', 's', 't', 'u', 'v', 'w', --112 (16#70#) .. 119 (16#77#) 'x', 'y', 'z', '{', '|', '}', '~', del, --120 (16#78#) .. 127 (16#7F#) reserved_128, reserved_129, bph, nbh, --128 (16#80#) .. 131 (16#83#) reserved_132, nel, ssa, esa, --132 (16#84#) .. 135 (16#87#) hts, htj, vts, pld, plu, ri, ss2, ss3, --136 (16#88#) .. 143 (16#8F#) dcs, pu1, pu2, sts, cch, mw, spa, epa, --144 (16#90#) .. 151 (16#97#) sos, reserved_153, sci, csi, --152 (16#98#) .. 155 (16#9B#) st, osc, pm, apc, --156 (16#9C#) .. 159 (16#9F#) ' ', '¡', '¢', '£', '¤', '¥', '¦', '§', --160 (16#A0#) .. 167 (16#A7#) '¨', '©', 'ª', '«', '¬', '', '®', '¯', --168 (16#A8#) .. 175 (16#AF#) '°', '±', '²', '³', '´', 'µ', '¶', '·', --176 (16#B0#) .. 183 (16#B7#) '¸', '¹', 'º', '»', '¼', '½', '¾', '¿', --184 (16#B8#) .. 191 (16#BF#) 'À', 'Á', 'Â', 'Ã', 'Ä', 'Å', 'Æ', 'Ç', --192 (16#C0#) .. 199 (16#C7#) 'È', 'É', 'Ê', 'Ë', 'Ì', 'Í', 'Î', 'Ï', --200 (16#C8#) .. 207 (16#CF#) 'Ð', 'Ñ', 'Ò', 'Ó', 'Ô', 'Õ', 'Ö', '×', --208 (16#D0#) .. 215 (16#D7#) 'Ø', 'Ù', 'Ú', 'Û', 'Ü', 'Ý', 'Þ', 'ß', --216 (16#D8#) .. 223 (16#DF#) 'à', 'á', 'â', 'ã', 'ä', 'å', 'æ', 'ç', --224 (16#E0#) .. 231 (16#E7#) 'è', 'é', 'ê', 'ë', 'ì', 'í', 'î', 'ï', --232 (16#E8#) .. 239 (16#EF#) 'ð', 'ñ', 'ò', 'ó', 'ô', 'õ', 'ö', '÷', --240 (16#F0#) .. 247 (16#F7#) 'ø', 'ù', 'ú', 'û', 'ü', 'ý', 'þ', 'ÿ', --248 (16#F8#) .. 255 (16#FF#) -- The predefined operators for the type Character are the same as for -- any enumeration type. -- The declaration of type Wide_Character is based on the standard ISO 10646 BMP character set. -- The first 256 positions have the same contents as type Character. See 3.5.2. type Wide_Character is (nul, soh ... FFFE, FFFF); package ASCII is ... end ASCII; --Obsolescent; see J.5 -- Predefined string types: type String is array(Positive range <>) of Character; pragma Pack(String); -- The predefined operators for this type are as follows: -- function "=" (Left, Right: String) return Boolean; -- function "/=" (Left, Right: String) return Boolean; -- function "<" (Left, Right: String) return Boolean; -- function "<=" (Left, Right: String) return Boolean; -- function ">" (Left, Right: String) return Boolean; -- function ">=" (Left, Right: String) return Boolean; -- function "&" (Left: String; Right: String) return String; -- function "&" (Left: Character; Right: String) return String; -- function "&" (Left: String; Right: Character) return String; -- function "&" (Left: Character; Right: Character) return String; type Wide_String is array(Positive range <>) of Wide_Character; pragma Pack(Wide_String); -- The predefined operators for this type correspond to those for String type Duration is delta ''implementation-defined'' range ''implementation-defined''; -- The predefined operators for the type Duration are the same as for -- any fixed point type. -- The predefined exceptions: Constraint_Error: exception; Program_Error : exception; Storage_Error : exception; Tasking_Error : exception; end Standard;
