Comments on: Coding: Keep method/variable names positive

By: Uttam Kini

Uttam Kini — Thu, 25 Feb 2010 03:51:00 +0000

Why not have a ValidPolicyNumber() method as well as InValidPolicyNumber, if readability is the concern.

private bool ValidPolicyNumber(string policyNumber)
{
string integerPattern = “^[0-9]{7}$”;
return policyNumber.Substring(0,5) == “POLIC” && Regex.IsMatch(policyNumber.Substring(6,7), integerPattern) && policyNumber.Length == 12
}

private bool InValidPolicyNumber(string policyNumber){

return !IsValidPolicyNumber(policyNumber);
}

By: Daily Links for Friday, June 12th, 2009

Daily Links for Friday, June 12th, 2009 — Fri, 12 Jun 2009 11:39:39 +0000

[...] Coding: Keep method/variable names positive at Mark Needham [...]

By: Andy Palmer

Andy Palmer — Fri, 12 Jun 2009 10:38:02 +0000

In this case, I agree with Mark that the InvalidPolicyNumber is hard to grok, and with Zach that the if statement reads better with the original name.
I would implement IsValidPolicyNumber as above, and then have IsInvalidPolicyNumber return !IsValidPolicyNumber.
You get the readability in both client and code then.

By: Mark Needham

Mark Needham — Fri, 12 Jun 2009 06:46:38 +0000

@Petar Good point I think that would make it even more readable in this case.

By: Petar Petrov

Petar Petrov — Fri, 12 Jun 2009 06:42:49 +0000

Hi Mark,
I always prefer to prefix my methods that return bool with Is, Has or Can it’s more readable. Take a look at these methods

IsValidPhoneNumber()
IsAccessAllowed()
CanConnectToServer()
HasMultipleComments()

in my opinion they have great names

By: Reflective Perspective - Chris Alcock » The Morning Brew #366

Reflective Perspective - Chris Alcock » The Morning Brew #366 — Thu, 11 Jun 2009 07:21:28 +0000

[...] Coding: Keep method/variable names positive – Mark Needham talks about a few techniques for keeping names of methods and variables easily understandable [...]

By: Zach Shaw

Zach Shaw — Thu, 11 Jun 2009 01:52:17 +0000

Hi Mark,

My 2 cents on this is, I like the method name InvalidPolicyNumber because it’s easier to read in your if statement (I don’t have to pay and attention to the ‘!’), I don’t disagree that writing a negative can be a little trickier, but I find that ‘&&’ or ‘||’ bugs are so common it helps to always split them out. For ex:

bool invalid = policyNumberSubstring(0,5) != “POLIC”;
invalid |= Regex.IsMatch(…) == false;
invalid |= policyNumber.Length != 12;
return invalid;

I find much easier to read than either of the above