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    <p>I hardly ever reuse variables. I hate to say never, but it is <em>close to never</em>.</p> <h2>Here is why:</h2> <ul> <li><em>Small methods</em> (It's good practice to keep methods and property-getters/setters as concise as possible). <ul> <li>When only one thing is done, <em>no need</em> to reuse variables</li> <li>The var section is always on the screen.</li> </ul></li> <li>The compiler reuses the storage as necessary, so reuse is only a <em>lazy coder crutch</em> with no performance improvements.</li> <li>Newer versions of Delphi have <strong>CTRL+SHIFT+V</strong> to declare a variable if I am feeling lazy.</li> <li>Reusing variables <em>makes debugging more difficult</em> - more time and effort is spent on maintenance then development (for any serious application) so always do things to <em>make maintenance easier</em>, even if it makes development a little harder.</li> <li>Prefer <em>user defined types</em>, so a Account Balance is a specific type, not just a Currency. This means variables are <em>less reusable</em> anyway.</li> <li><strong>For</strong> loop variables (a common reused variable) are used less now that we can use <strong>for in</strong> and <em>skip the iterator</em> all together.</li> <li>My variables have <em>descriptive names</em>, so it would not make sense to use them out of context. </li> </ul> <p>Generally speaking, I like having all the variables at the top for the same reason I like having an interface section on my units. It is kind of like having an abstract on a paper - give me a general idea of what is going on without having to read the whole paper. Delphi could benefit from having the ability to declare variables at "inner scope" like within a <strong>for</strong> loop or other <strong>begin / end</strong> blocks, but I don't know how much that would distract from the cleanliness and readability of Delphi code.</p>
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    1. POWith Delphi are you more likely to re-use temporary variables than with other languages?
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    1. USJim McKeeth
    1. USJim McKeeth
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    1. COOK, maybe you're in control of more code than I am, but given a situation where you have 50 string fields in a table and you need to assign them to some labels' caption property and the function you're given to access data from the database requires a VAR parameter, so you can't pass in label1.caption. Then I'll bet you'd use something like getfield('thisstring', tempstr); label1.caption := tempstr; getfield('thisotherstring', tempstr); label2.caption := tempstr; etc... etc... etc.... Yea or Nay?
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      1. USPeter Turner
    2. CO@Peter: I would create a procedure that does that for me, so I just pass ('thisstring', label1) and it does the GetFeild() and .caption := for me. Maybe even I would setup a way to pass a list of fields and labels, or even create a way to associate the two with each other. If you are working somewhere you can't create a helper procedure then you need to look for a new job. BTW, my company is hiring, and we let you write good code.
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