Comparison of Pascal and Delphi: Difference between revisions

Revision as of 01:14, 17 January 2020

Revision as of 17:34, 11 May 2020

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4. Given a variant record in Standard Pascal, the size of a particular variant can be specified. Delphi does not support this form of 'sized' dynamic variable allocation:

<sourcesyntaxhighlight lang="pascal">

new(p, t) //where t is a variant record tag type; does not compile in Delphi

</syntaxhighlight>

</source>

5. The functions 'pack' and 'unpack' are not implemented in Delphi.

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6. The Delphi compiler does not treat { and (*, } and *) as synonyms like Standard Pascal requires. In other words,

<sourcesyntaxhighlight lang="delphi">

{ comment *)

</syntaxhighlight>

</source>

is not valid in Delphi. Instead, Delphi uses the scheme of allowing the different comment types to indicate nested comments.

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8. Numbers and booleans are not printed out in their 'default' field widths by Delphi's version of the Write and WriteLn standard procedures, being instead printed in the minimum amount of space. For example, in Delphi,

<sourcesyntaxhighlight lang="delphi">

write(5);

write(55);

</syntaxhighlight>

</source>

is equivalent to:

<sourcesyntaxhighlight lang="pascal">

write(5:1);

write(55:2);

</syntaxhighlight>

</source>

However, Standard Pascal requires it to be equivalent to the following (TotalWidth is implementation-defined):

<sourcesyntaxhighlight lang="pascal">

write(5:TotalWidth);

write(55:TotalWidth);

</syntaxhighlight>

</source>

Similarly, for booleans,

<sourcesyntaxhighlight lang="pascal">

write(false);

write(true);

</syntaxhighlight>

</source>

is equivalent to

<sourcesyntaxhighlight lang="delphi">

write('false':5);

write('true':4);

</syntaxhighlight>

</source>

in Delphi, but

<sourcesyntaxhighlight lang="pascal">

write('false':TotalWidth);

write('true':TotalWidth);

</syntaxhighlight>

</source>

in ISO 7185.