I’m sorry for going back to the IIF discussion but…It took me a while to read the posts and then I felt embarrassed because my own opinion differs in so many regards from respected members of the FoxPro community.

IF …ELSE … ENDIF
Several people stated that they consider it a bad coding practice to have an IF without an ELSE. I would prefer to say that one should always think about the ELSE but I don’t believe one should always code it. Indeed applied mechanically one can have truly horrendous code like the following:

if  vartype(tMan) <> “C”
	Return this.throwerror(“Bad Man”)
else
	if vartype(tPhilosopher)<>”C”
		Return this.throwerror(“Bad Philosopher”)
	Else
		* now go ahead and execute the function…
		
	endif
endif

I know that none of you would code like this because it disobeys the rule to keep your logical structures flat but someone new or from another language might obey the rule literally.

Another example: suppose you have a program for making soup one might have look like:

if not this.lEnoughSalt
	this.AddSalt()
endif
if not this.lEnoughPepper
	this.AddPepper()
endif

with many many if conditions. I believe adding ELSE decreases the readability of the function by almost doubling the length of the code -- assuming you add a comment in the else. If you don't have a comment any maintenance programmer is going to assume that you just forgot to code the else and will spend an hour trying to deduce what ought to be there!

Using the IF ELSE to replace logical expressions

if a=b
   c=.f.
else
   c=.t.
endif

There are couple reasons why I think people use the if else
a) in FoxPro the assignment operator (=) is the same as the equality operator (=) this makes expressions like
c=b=a hard to read even though they are sompletely valid.

b) The IF construction follows the english language better.

c) While in semantic logic we have the conditional (->) operator most computer languages don't have one-- instead restricting themselves to AND, OR, NOT, >,= etc. so there may be a tendency to replace the nonexistant IF operator with the existant IF ELSE ENDIF command I don't know because I couldn't come up with any good real world examples.

d) if else can be used to make an OR

llIsGeologist = .f.
if (llHasPulse AND ...)
  llIsGeologist = .t.
endif
if (llHasBeard AND ...)
  llIsGeologist = .t.
endif

really means

llIsGeologist = (llHasBeard AND ...) OR (llHasPulse AND ...)

this could have been coded

llIsGeologist = (llHasBeard AND ...) 
llIsGeologist = llGeologist OR (llHasPulse AND ...)

but the first version is probably the easiest to read.

I don't use the if else to build expressions very often because (which brings us back to the first point) they don't have closure. If the llIsGeologist is not anywhere above then the program will crash sometimes: i.e. an easy way to make a bug that may not come out in testing. So I only use the if when I have expressions that I can't understand anymore because of their complexity.

iif
Couldn't agree with you more. Curiously I accidentally changed mz kezboard to German and can't fix it. So I apologise for any typing errors.

DeMorgans Rule and Logical Transformations
Sometimes I see people (particularly smart ones) simplifying expressions with logical transformations. For example for the rule “Programmers cannot have salary more than 50000” I saw the expression

JOB<>’Pgmr’ or SAL < 50000

instead of

NOT (JOB = “Pgmr” and SAL>=50000)

the two expressions are logically equivalent but I find the first difficult to comment while the second requires no comment at all! I think logical transformations are worth thinking about: sometimes one gets an insight when one transforms an expression but only use the transformation if the new expression can be understood in natural speech. Pity the poor maintenance programmer!