Re: Evaluating Exceptions, Try Except and Try Finally

From: Skybuck Flying (nospam_at_hotmail.com)
Date: 04/08/04 

Date: Thu, 8 Apr 2004 19:30:54 +0200

YOU CALL THIS CLEAR DOCUMENTATION ?!?!?!?!?!?!?!?!?!?! :)

Try...finally Statements Sometimes you want to ensure that specific parts of
an operation are completed, whether or not the operation is interrupted by
an exception. For example, when a routine acquires control of a resource, it
is often important that the resource be released, regardless of whether the
routine terminates normally. In these situations, you can use a
try...finally statement. The following example shows how code that opens and
processes a file can ensure that the file is ultimately closed, even if an
error occurs during execution.

Just ignore this example :P
Reset(F);
try
   ... // process file F
finally
   CloseFile(F);
end;The syntax of a try...finally statement is try statementList1 finally
statementList2 end where each statementList is a sequence of statements
delimited by semicolons. The try...finally statement executes the statements
in statementList1 (the try clause). If statementList1 finishes without
raising exceptions, statementList2 (the finally clause) is executed. If an
exception is raised during execution of statementList1, control is
transferred to statementList2; once statementList2 finishes executing, the
exception is re-raised. If a call to the Exit, Break, or Continue procedure
causes control to leave statementList1, statementList2 is automatically
executed. Thus the finally clause is always executed, regardless of how the
try clause terminates. If an exception is raised but not handled in the
finally clause, that exception is propagated out of the try...finally
statement, and any exception already raised in the try clause is lost. The
finally clause should therefore handle all locally raised exceptions, so as
not to disturb propagation of other exceptions.

HOW THIS THAT MORE EASY TO UNDERSTAND THEN A SIMPLE IF ELSE STATEMENT
!!!!!!!!!!!!!!!!!!!!!!!!!!!!

OF *** IT LOL :)

THE IF THEN ELSE STATEMENT DOCUMENTATION IS JUST AS FUCKED :)'

"

If Statements There are two forms of if statement: if...then and the
if...then...else. The syntax of an if...then statement is if expression then
statement where expression returns a Boolean value. If expression is True,
then statement is executed; otherwise it is not. For example,
if J <> 0 then Result := I / J;The syntax of an if...then...else statement
is if expression then statement1 else statement2 where expression returns a
Boolean value. If expression is True, then statement1 is executed; otherwise
statement2 is executed. For example,
if J = 0 then
   Exit
else
   Result := I / J;The then and else clauses contain one statement each, but
it can be a structured statement. For example,
if J <> o then
  begin
    Result := I / J;
    Count := Count + 1;
  end
else if Count = Last then
        Done := True
else
  Exit;
            Notice that there is never a semicolon between the then clause
and the word else. You can place a semicolon after an entire if statement to
separate it from the next statement in its block, but the then and else
clauses require nothing more than a space or carriage return between them.
Placing a semicolon immediately before else (in an if statement) is a common
programming error. A special difficulty arises in connection with nested if
statements. The problem arises because some if statements have else clauses
while others do not, but the syntax for the two kinds of statement is
otherwise the same. In a series of nested conditionals where there are fewer
else clauses than if statements, it may not seem clear which else clauses
are bound to which ifs. Consider a statement of the form if expression1 then
if expression2 then statement1 else statement2; There would appear to be two
ways to parse this: if expression1 then [ if expression2 then statement1
else statement2 ]; if expression1 then [ if expression2 then statement1 ]
else statement2; The compiler always parses in the first way. That is, in
real code, the statement
if ... { expression1} then
  if ... {expression2} then
    ... {statement1}
  else
    ... {statement2}is equivalent to
if ... {expression1} then
  begin
    if ... {expression2} then
      ... {statement1}
    else
      ... {statement2}
end;The rule is that nested conditionals are parsed starting from the
innermost conditional, with each else bound to the nearest available if on
its left. To force the compiler to read our example in the second way, you
would have to write it explicitly as
if ... {expression1} then
  begin
   if ... {expression2} then
     ... {statement1}
   end
end
else
   ... {statement2};"Sigh.Skybuck :)