RE: Re: Refactoring wishlist

Hi George,

 

CodeRush (for Visual Studio) does all of these if-statement manipulations
that you’re requesting out of the box, except for 11:

 

Ø  11. Remove a simple "return", "continue", or "break" statement that is
nested under an if-then or if-then-else so that the return is done at the
end of the block. Of course a resulting simple "return", "continue", or
"break" at the end of the method should disappear.

 

…which doesn’t seem like a refactoring to me, unless I’m misunderstanding
it. 

 

CodeRush also has refactorings to combine in-series or nested conditionals
and split complex conditionals into multiple nested or in-series if
statements, which can be interesting (in-series combinations require/produce
identical child blocks).

 

- Mark Miller

  DevExpress

  C# MVP

  @MillerMark

 

From: [email protected] [mailto:[email protected]] On
Behalf Of George
Sent: Monday, September 26, 2011 1:45 PM
To: [email protected]
Subject: [refactoring] Re: Refactoring wishlist

 

  



I've done some awkward cleanup of if-statements lately. It's especially
frustrating to reverse the sense of relatively complex boolean conditions or
otherwise simplify their expression. Here are some refactorings that woul
help, roughly in order of difficulty.

1. Reverse the sense of a boolean expression. I guess this is just adding
"!(...)" around it. If someone was negating a single variable or method call
you'd want to avoid inserting extra parentheses.
If the expression already contained a top level "!" you'd want to remove
both. Leave the resulting expression highlighted and ready to apply another
refactoring. 

2. Remove redundant parentheses is an expression.

2. Remove double negatives throughout an expression.

4. Distribute AND over OR (or OR over AND).

5. Change a boolean expression to conjunctive normal (or disjunctive
normal).

6. Apply DeMorgan's law to an expression.

7. Reverse the sense of a boolean variable. For instance, if I have a
variable named "missing" and I realize that everything reads better if it is
named "found", I need to rename it, reverse it's initial value, reverse any
assignments to it, place a not (!) in front of every use, and remove any
resulting double negations.

8. Switch the sense of an if statement's condition while reversing the then
and else clauses.

9. Change an if-then statement to an if-then-else statement or vice versa.

10. Switch the sense of an if statement's condition where the statement
contains only the then clause, ending up with an if-then-else. This might
require duplicating code unless the original then-clause ends with "return",
"break", or "continue".

11. Remove a simple "return", "continue", or "break" statement that is
nested under an if-then or if-then-else so that the return is done at the
end of the block. Of course a resulting simple "return", "continue", or
"break" at the end of the method should disappear.

12. The reverse of 10. Change an if-then-else at the end of a block to an if
with a "return", "continue", or "break", depending on context.

If you can get both 8 and 10 done, they should probably be combined into a
single refactoring. Maybe other refactorings of refactorings could be done
to make these apply to problems programmers have as opposed to abstract
boolean manipulation.



[Non-text portions of this message have been removed]



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