Comparison of Pascal and Delphi

Following features are mutually exclusive.

The Standard Pascal implementation is not accepted by Delphi and vice versa, the Delphi code is not acceptable in Standard Pascal.

Standard Pascal has a Euclidean-like definition of the mod operator whereas Delphi uses a truncated definition.

Standard Pascal requires that the comment delimiters { and the bigramm (*, as well as } and *) are synonymous to each other.

In Delphi, however, a block comment started by { must be closed with a }.

The bigramm *) will only close any comment that started with (*.

This scheme allows for nested comments at the expense of compiler complexity.

The way procedures and functions can be passed as parameters differs:

Delphi requires explicit procedural types to be declared where Standard Pascal does not.

Various computer systems show a wide variety how to indicate a newline.

This affects the internal representation of text files which are composed of a series of “lines”.

In order to relieve the programmer from any associated headaches, Standard Pascal mandates that reading an “end-of-line character” returns a single space character.

To distinguish such an “end-of-line” space character from a space character that is actually genuine payload of the line, EOLn becomes true.

Delphi does not show this behavior.

Reading a newline will return whatever character sequence represents a newline on the current host system, for example two char values chr(13) (carriage return) plus chr(10) (line feed).

Following features are present or missing in either language.

Standard Pascal permits a goto to any label defined in scope.

In Delphi a goto must be within the current routine, i. e. may not leave the begin … end-frame.

program jumpAround;

label

999;

procedure foo;

begin

{ This is not permitted in Delphi: }

goto 999;

end;

begin

foo;

999: ;

end.

Delphi does not support buffer variables and associated standard routines get and put.

program copy(input, output);

begin

while not EOF(input) do

begin

{ Copy file buffers. Not supported by Delphi }

output↑ := input↑;

{ Input↑ contains a space if a new-line occurred. }

if EOLn(input) then

begin

writeLn(output);

end

else

begin

put(output);

end;

{ Advance reading cursor. }

get(input);

end;

end.

In Standard Pascal allocating memory for a variant record may indicate a specific variant.

This allows implementations to allocate the least amount of really necessary memory.

Delphi does not support this.

program variantRecord;

type

sex = (female, male);

clothingMeasures = record

girth: real;

case gender: sex of

female: (underbust: real);

male: ( );

end;

var

size: clothingMeasures;

begin

{ NB: No space allocated for `underbust`. }

new(size, male);

end.

In Delphi any file must be backed by a file in the file system.

That means any file needs to be associated with a file name with Delphi's assign procedure.

In contrast, Standard Pascal is usable without file names.

The following will produce a run-time error with Delphi.

program temporaryFile(output);

var

FD: text;

begin

rewrite(FD);

writeLn(FD, 'Hello world!');

end.

Delphi does not implement the standard procedures pack and unpack.

Regardless, transferring data between packed and unpacked data types is an easy feat, although the implementation might not be as efficient as a compiler vendor supplied implementation would be.

Delphi does not associate the data type Boolean with a default width if specified as write/writeLn parameters.

Delphi demonstrates the behavior as usual for character-strings.

Delphi permits overloading routines.

In Standard Pascal identifiers must be unique in every block.

function f(x: integer): real;

begin

result := sin(x);

end;

function f(x: real): real;

begin

result := cos(x);

end;

// ─── MAIN ─────────────────────────────────────────────

begin

// Note the different data types.

writeLn(f(3));

writeLn(f(3.0));

end.

Delphi permits default parameters.

In Pascal, if the destination file is a text file, the parameters to write/writeLn have an implemention-defined default total width.

In Delphi, for integer values this is simply 1.

That means always the least amount of space is occupied.

Other compilers have shown default widths of, for example, 20 allowing for a fine tabular look at no cost of extra code.

{{cite web

| title = The GNU Pascal Manual

| first1 = Jan-Jaap

| last1 = van der Heijden

| first2 = Peter

| last2 = Gerwinski

| first3 = Frank

| last3 = Heckenbach

| first4 = Berend

| last4 = deBoer

| first5 = Dominik

| last5 = Freche

| first6 = Eike

| last6 = Lange

| first7 = Peter

| last7 = Lewis

| display-authors = etal

| at = A QuickStart Guide from Borland Pascal to GNU Pascal

| url = https://www.GNU-Pascal.de/gpc/Comments.html#Comments

| access-date = 2023-04-24

}}

{{cite web

| title = Pascal Standards FAQ

| at = Comparison of Borland Pascal to the Pascal standards

| first = John

| last = Reagan

| date = 1995-04-03

| url = http://Pascal-Central.com/extpascal.html#anchor-6

| archive-url = https://web.archive.org/web/20210928162340/http://pascal-central.com/extpascal.html#anchor-6

| archive-date = 2021-09-28

}}

{{cite web

| title = Standard Pascal FAQ

| at = Q. What are the differences between Borland Delphi and the ISO 7185 standard?

| first = Scott

| last = Moore

| date = 2022-12-02

| url = https://www.MooreCAD.com/standardpascal/pascalfaq.html#Q.%20What%20are%20the%20differences%20between%20Borland%20Del

| access-date = 2023-04-24

}}

• Kathleen Jansen and Niklaus Wirth: PASCAL - User Manual and Report. Springer-Verlag, 1974, 1985, 1991, {{ISBN|0-387-97649-3}}, {{ISBN|0-387-90144-2}}, and {{ISBN|3-540-90144-2}} [https://web.archive.org/web/20050314152247/http://www.cs.inf.ethz.ch/~wirth/books/Pascal/]
• Niklaus Wirth: The Programming Language Pascal. Acta Informatica, 1, (Jun 1971) 35–63
• ISO/IEC 7185: Programming Languages - PASCAL. [http://www.moorecad.com/standardpascal/]
• Doug Cooper: Standard Pascal: User Reference Manual. W. W. Norton & Company, 1983, {{ISBN|0-393-30121-4}}, {{ISBN|978-0-393-30121-2}}

• [https://www.moorecad.com/standardpascal/ The ISO 7185 Pascal web site]
• [https://www.StandardPascal.org/standards.html Pascal standards documents]

{{Pascal programming language family}}

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Category:Pascal programming language family

Category:Borland

Category:Comparison of individual programming languages