OpenEuphoria

1. Syntax for OR

• Posted by cp Mar 03, 2015
• 1743 views

It seems that this syntax is supported ?

if seqConn[1] = 1 or 3 then 

and is equivalent to..

if seqConn[1] = 1 or seqConn[1] = 3 then 

casey

3. Re: Syntax for OR

• Posted by katsmeow Mar 03, 2015
• 1675 views

Use parentheses liberally, they come free with each OE installation.

if seqConn[1] = (1 or 3) then 

5. Re: Syntax for OR

• Posted by DerekParnell (admin) Mar 04, 2015
• 1644 views

if seqConn[1] = (1 or 3) then 

I'm sorry Lonny, but what isn't correct? The syntax is correct. The use of parenthesis is correct. The intended result maybe correct, if we knew what the code intended by the code. So without that sort of context, it would be presumptuous to assume that Kat's code is "incorrect".

(1 or 3) = 1 
-- so if  
seqConn[1] = 3 
-- then seqConn[1] = (1 or 3) will be false 

But ...

(1 or 3) = 1 
-- so if  
seqConn[1] = 1 
-- then seqConn[1] = (1 or 3) will be true 

So maybe you might have been more accurate to say something along the lines of ...

7. Re: Syntax for OR

• Posted by jimcbrown (admin) Mar 04, 2015
• 1673 views

Erm, you state it below:

From the context of the original post, I interpreted katsmeow's post to mean:

And I think that's a reasonable interpretation of katsmeow's words.

I would think OP's post provides enough context... if katsmeow intended to speak about something different, then I think that katsmeow should have provided additional context herself to make this clear. (OTOH, when posting in a hurry or on the run, it's possible to make minor mistakes and forget to include things. It happens, it's no big deal, the important bit is to obtain clarification after the fact. It's also possible that this is a "joke" post, where katsmeow is trying to alert the OP about the possible traps due to the lack of an explicit boolean type in Euphoria - but in that case, some initial confusion is to be expected.)

After spending several minutes rereading this line, I still do not understand what it means.

9. Re: Syntax for OR

• Posted by jimcbrown (admin) Mar 04, 2015
• 1615 views

Agreed. No argument from me here.

Good point. I concede.

D'oh!

11. Re: Syntax for OR

• Posted by ghaberek (admin) Mar 04, 2015
• 1624 views

if find(seqConn[1],{1,3})!=0 then 

Came here to say this. Leaving satisfied.

-Greg

13. Re: Syntax for OR

• Posted by _tom (admin) Mar 04, 2015
• 1620 views

if seqConn[1] = 1 or 3 then 

if seqConn[1] = 1 or seqConn[1] = 3 then 

The way to resolve a syntax question is to write some code!

• Simplify: seqConn[1] could be an object; test with atoms first
• Execute: write some working code

 
--        test by runnning different values 
--        |   
--        v 
atom sc = 2 
 
if sc = 1 or 3 then 
    puts(1, "found" ) 
else 
    puts(1, "not found" ) 
end if 
 
 
--> found 
    -- not the intended result 

What is going on?

Order of operations means sc = 1 is evaluated first. The result of this snippet may be either 0 (false) or 1 (true).

Next you evaluate one of two possible remaining expressions. You need to refer to logic true tables for this:

0 or 3    -- true 
1 or 3    -- true 

The "surprise" is that you always get true.

atom sc = 2 
 
if sc = 1 or sc = 3 then 
    puts(1, "found" ) 
else     
    puts(1, "not found" ) 
end if 
     
--> not found 

This code makes more sense.

atom sc = 3 
 
if sc = ( 1 or 3 ) then 
    puts(1, "found" ) 
else 
    puts(1, "not found" ) 
end if 
 
--> not found 

The parentheses get evaluated first:

1 or 3  -- true 

Next you evaluate

sc = 1 

Since 3 does not equal 1 you get "not found" which is not the "intended" result. The "trap" in this example that sc=1 works as intended and all other values work as intended.

atom sc = 2 
 
if find( sc, {1,3} ) then 
    puts(1, "found" ) 
else 
    puts(1, "not found" ) 
end if 
 
--> not found 

This works as "intended."

An alternative approach:

atom sc = 3 
 
switch sc do 
    case 1, 3 then 
        puts(1, "found" ) 
    case else 
        puts(1, "not found" ) 
end switch 
 
--> found 

_tom

15. Re: Syntax for OR

• Posted by jimcbrown (admin) Mar 04, 2015
• 1675 views

Good point. The OP - using a gender-neutral name - did not say which test was intended:

if seqConn[1] = 1 or 3 then 

Or

if seqConn[1] = 1 or seqConn[1] = 3 then 

If I had to guess though, I'd go with the second one. It seems very unlikely that the first test would ever be intended, since it is always true (and not in a place like a loop where one might want an always true test to perform an infinite loop).

17. Re: Syntax for OR

• Posted by jimcbrown (admin) Mar 04, 2015
• 1657 views

But you did.

But (unless both numerals are zero) it's always reduced to the same value, regardless. I don't see how typing '(1 or 3)' is easier than just typing '1'.

Aha! So Derek's interpretation was slighly off - this was a secondary point, not a major point!

I also support having the OP making nirs code as readable as possible by proper use of parentheses, as you suggest below.

Absolutely.

You guessed correctly.

19. Re: Syntax for OR

• Posted by jimcbrown (admin) Mar 04, 2015
• 1609 views

Here's your response. I stand by my statement.

if seqConn[1] = (1 or 3) then 

It is always reduced by the interpreter.

Conceded. Still sounds like this should be (slightly) harder, not easier.

Edit: Basically, I see this as meaning both Derek and I were off. But Derek's version was a whole lot closer and thus more correct than mine.

I think this merely reaffirms Derek's main point - for the purposes of clarity, it's best to spell out as much as possible, including what one's assumptions are.

I haven't been keeping track.

I'm not openly questioning the gender of the OP. I don't care about that, I'm simply refusing - unlike some others here - to assume that the OP is male until told otherwise.

Then, perhaps it makes sense to take things off of the forum here. I think you and others have already provided all the necessary technical information to the OP to answer the OP's original question from all angles.

With that in mind, if you wish to make a response to this post, I invite you to reply to me privately through either _tom or ChrisB, by emailing them.

21. Re: Syntax for OR

• Posted by jimcbrown (admin) Mar 04, 2015
• 1601 views

Hmm. It's even worse than that. _tom's most current email has never been posted on the forum, so even shifting through posts won't help here.

Let me think about this. I'll have one of the other admins get back to you with a solution in a few days at most.