Ada 2012 Reference Manual

5.6 Block Statements

block_statement ::=
[block_statement_identifier:]
[declare
declarative_part]
begin
handled_sequence_of_statements
end [block_identifier];

If a block_statement has a block_statement_identifier, then the identifier shall be repeated after the end; otherwise, there shall not be an identifier after the end.

A block_statement that has no explicit declarative_part has an implicit empty declarative_part.

The execution of a block_statement consists of the elaboration of its declarative_part followed by the execution of its handled_sequence_of_statements.

Example of a block statement with a local variable:

Swap:
declare
Temp : Integer;
begin
Temp := V; V := U; U := Temp;
end Swap;