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Higher-order functions: Difference between revisions
→[[Ada]]: Added a more complex example
(→[[Ada]]: Added a more complex example) |
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==[[Ada]]==
[[Category:Ada]]
===Simple Example===
with Ada.Text_Io; use Ada.Text_Io;
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First(Second'Access);
end Subprogram_As_Argument;
===Complex Example===
with Ada.Text_Io; use Ada.Text_Io;
procedure Subprogram_As_Argument_2 is
-- Definition of an access to long_float
type Lf_Access is access Long_Float;
-- Definition of a function returning Lf_Access taking an
-- integer as a parameter
function Func_To_Be_Passed(Item : Integer) return Lf_Access is
Result : Lf_Access := new Long_Float;
begin
Result.All := 3.14159 * Long_Float(Item);
return Result;
end Func_To_Be_Passed;
-- Definition of an access to function type matching the function
-- signature above
type Func_Access is access function(Item : Integer) return Lf_Access;
-- Definition of an integer access type
type Int_Access is access Integer;
-- Define a function taking an instance of Func_Access as its
-- parameter and returning an integer access type
function Complex_Func(Item : Func_Access; Parm2 : Integer) return Int_Access is
Result : Int_Access := new Integer;
begin
Result.All := Integer(Item(Parm2).all / 3.14149);
return Result;
end Complex_Func;
-- Declare an access variable to hold the access to the function
F_Ptr : Func_Access := Func_To_Be_Passed'access;
-- Declare an access to integer variable to hold the result
Int_Ptr : Int_Access;
begin
-- Call the function using the access variable
Int_Ptr := Complex_Func(F_Ptr, 3);
Put_Line(Integer'Image(Int_Ptr.All));
end Subprogram_As_Argument_2;
==[[C]]==
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