Programación en Ada/Unidades predefinidas/Standard
Paquete Standard
[editar]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.
Especificación
[editar]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;