Extended Pascal
Dialect of programming language PascalA dialect of Pascal, as defined by standard ISO 10206 (1990).
Features not found in Standard Pascal:

added operators
**
(exponentiation),><
(set symmetric difference) and=>
(rename identifiers at import/export). 
added keywords
AND_THEN, BINDABLE, EXPORT, IMPORT, MODULE, ONLY, OR_ELSE, OTHERWISE, POW, PROTECTED, QUALIFIED, RESTRICTED, VALUE
(mostly related to modularity and short circuit boolean evaluation).  modularity and separate compilation. Each module exports an interface which makes entities of this module available from other modules.
 schemata — collections of similar types.
 new string processing capabilities.
 variables binding.
 direct access file processing, adding data to the end of the file.
 constant expressions.
 structured value constructors.
 generalized function returns.
 setting initial state for a variable enabled.
 order of declarations relaxed (no forward references).
 type inquiry: a variable/parameter can be declared having type of another variable/parameter.

constants
maxchar, minreal, maxreal
andepsreal
allow to get details of implementation ofchar
andreal
data types. 
case
statement improved: caseconstantlist can contain ranges of values, andotherwise
clause represents all values not listed before.  extension of set operations: symmetric difference, function to query number of elements in set and forloop to iterate through the elements.

TimeStamp
data type and related functions for time processing.  standard means of numeric input added.
 representation of integer numbers using bases 2..36.

underscore (
_
) can be used in identifiers. 
write
can accept zero as field width parameters. 
added
halt
procedure to stop program execution.  added complex numbers data type.
 short circuit boolean evaluation.
 protected parameters (can’t be modified within the procedure they are passed to).
 exponentiation operation added.
 conformant arrays.
Examples:
Quadratic equation:
Example for versions Free Pascal 2.0.4, Free Pascal 2.2.0, Turbo Pascal 1.0, Turbo Pascal 2.0, Turbo Pascal 3.0, Turbo Pascal 4.0, Turbo Pascal 5.0, Turbo Pascal 6.0, gpc 20070904Pascal has builtin complex data type complex
, but using it is inconvenient in this case, because writeln
can’t output complex numbers directly, and functions Re
and Im
would have to be used. In this example calculations are done in real numbers. Library function halt
(added in Extended Pascal) exits current block (in later versions it is replaced with exit
).
program Quadratic;
var
A,B,C,D: integer;
begin
write('A = ');
readln(A);
if (A=0) then
begin
writeln('Not a quadratic equation.');
halt;
end;
write('B = ');
readln(B);
write('C = ');
readln(C);
D := B*B4*A*C;
if (D=0) then
begin
writeln('x = ',B/2.0/A);
halt;
end;
if (D>0) then
begin
writeln('x1 = ',(B+Sqrt(D))/2.0/A);
writeln('x2 = ',(BSqrt(D))/2.0/A);
end
else
begin
writeln('x1 = (',B/2.0/A,',',Sqrt(D)/2.0/A,')');
writeln('x2 = (',B/2.0/A,',',Sqrt(D)/2.0/A,')');
end;
end.
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