How to split long string in several row in Delphi code source?

Question

In delphi, in the code source, sometime you need to write quite long string that is hard to keep on a single row like

'SELECT Email FROM Employee where NOT REGEXP_LIKE(Email, ‘[A-Z0-9._%+-]+@[A-Z0-9.-]+\.[A-Z]{2,4}’, ‘i’);'

but in the code source to make it more readable you must split it in several rows like

'SELECT '+
  'Email '+
'FROM '+
  'Employee '+
'where '
  'NOT REGEXP_LIKE(Email, ‘[A-Z0-9._%+-]+@[A-Z0-9.-]+\.[A-Z]{2,4}’, ‘i’);'

but doing this (as far as i understand) will involve concatenation of string at run time and the compiler will also create internally several temp string to handle theses concatenations

So how efficiently in the code source split a long string on several row under delphi without affecting the performance ?

Nothing is done at runtime. The compiler does this at compile time and in both cases there will be one single constant string. So this is just a matter of preference and layout of your source code, nothing else. — Rudy Velthuis
– Rudy Velthuis, Commented Mar 18, 2018 at 9:13

David Heffernan · Accepted Answer · 2018-03-18 08:02:41Z

5

There is no performance issue with your second block of code. The compiler performs the concatenation at compile time. The two expressions in your question are treated identically. Both of these are constant expressions.

answered Mar 18, 2018 at 8:02

David Heffernan

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