Delphi reserved words and identifiers

Question

Declaring variables in Delphi brought me to consider a thing that I can't understand.

The question is this: declaring strings, one can observe that string is a reserved word, while declaring other data types, say integers, the data type qualifier is not a reserved word but an identifier (i.e. Integer, the capital I tells so).

In fact, Delphi lets you go to the definition of Integer, which you discover it is contained within the System unit, but it is only representative, because there is a comment stating that some constants (like True), identifiers (like Integer), functions and procedures are directly built into the compiler.

I can't figure out the reasons behind this choice.

Could someone help?

---

A little explanation of the difference between string and Integer types. The next code

type
  Integer = Char;

var
  I: Integer;

begin
  I:= 'A';
  ShowMessage(I);
end;

is correct and works as expected, while the next line

type
  string = Integer;

gives compile-time error.

Answer 1

As far i know string is a reserved word since the Turbo Pascal times. So the reason to keep it in this way must be for compatibility.

Pascal -> Turbo Pascal - > Object Pascal -> Delphi.

Check these resources.

• The Pascal Programming Language (this shows the original reserved word of Pascal, without string)
• Turbo_Pascal Version 6.0 Programmers Guide (this shows how the string is a reserved word)