[SOLVED] „Error: Constant and CASE types do not match‟ with string
lazarus / 62-General

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CM630 · 2018-07-09 13:31

Following code works right:
Code: Pascal  [Select][+][-]window.onload = function(){var x1 =
document.getElementById("main_content_section"); if (x1) { var x =
document.getElementsByClassName("geshi");for (var i = 0; i  procedure
TForm1.Button1Click(Sender: TObject);var  A: string='';  B: string=
'B';  C: string= 'C';begin  A:=B;  case A of    'B': ShowMessage (B); 
  'C': ShowMessage (C);  end;end;

But this code generates „Error: Constant and CASE types do not match‟.
Code: Pascal  [Select][+][-]window.onload = function(){var x1 =
document.getElementById("main_content_section"); if (x1) { var x =
document.getElementsByClassName("geshi");for (var i = 0; i procedure
TForm1.Button1Click(Sender: TObject);var  A: string='';  B: string=
'B';  C: string= 'C';begin  A:=B;  case A of    B: ShowMessage (B);  
C: ShowMessage (C);  end;end;

B and C are strings. I tryed to cast to cast them to strings, anyway,
but still I get the same error?
Is it me doing sth. wrong?

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RayoGlauco · 2018-07-09 13:49

In the second example, you use variables as selectors, instead of
constants (B is a variable; 'B' is a constant). You cannot use
variables as selectors.

See http://wiki.freepascal.org/Case

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Thaddy · 2018-07-09 13:50

Needs a literal value, indeed.

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Gammatester · 2018-07-09 13:50

You should read the second part of the error message 'Error: String
expression expected'. The case labels must be constants (i.e. literals
or true constants). Your construct would throw equivalent message even
for integer variables. The following code does work:
Code: Pascal  [Select][+][-]window.onload = function(){var x1 =
document.getElementById("main_content_section"); if (x1) { var x =
document.getElementsByClassName("geshi");for (var i = 0; i var  A:
string='';const  B = 'B';  C = 'C';begin  A:=B;  case A of    B:
writeln (B);    C: writeln (C);  end;end;

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CM630 · 2018-07-09 13:57

Ok, thanks, I will rewrite it with QuoteIf... then.