Exceptions: Difference between revisions

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 =={{header|Ada}}==
 ===Define an exception===
+<ada>
-  Foo_Error : Exception;
+Foo_Error : exception;
+</ada>
 ===Raise an exception===
+<ada>
-  procedure Foo is
+procedure Foo is
-  begin
+begin
-     raise Foo_Error;
+   raise Foo_Error;
-  end Foo;
+end Foo;
+</ada>
+Re-raising once caught exception:
+<ada>
+  ...
+exception
+   when Foo_Error =>
+      if ... then -- Alas, cannot handle it here,
+         raise;   -- continue propagation of
+      end if;
+</ada>
 ===Handle an exception===
+<ada>
-  procedure Call_Foo is
+procedure Call_Foo is
-  begin
+begin
-     Foo;
+   Foo;
-  exception
+exception
-     when Foo_Error =>
+   when Foo_Error =>
-       -- do something
+      ... -- do something
-  end Call_Foo;
+   when others =>
+      ... -- this catches all other exceptions
+end Call_Foo;
+</ada>
+===Ada.Exceptions===
+The standard package Ada.Exceptions provides a possibility to attach messages to exceptions, to get exception occurrence information and textual description of exceptions. The following example illustrates basic functionality of:
+<ada>
+with Ada.Exceptions;  use Ada.Exceptions;
+with Ada.Text_IO;     use Ada.Text_IO;
+procedure Main is
+begin
+   ...
+   Raise_Exception (Foo_Error'Identity, "This is the exception message");
+   ..
+exception
+   when Error : others =>
+      Put_Line ("Something is wrong here" & Exception_Information (Error));
+end Main;
+</ada>
 =={{header|AppleScript}}==
 ===try===