Another easy one:

[PhilOfPerth]

Typing Print val("3*3") returns 3.
I would expect it to return 9. I don't see anything to indicate differently.

[a740g]

This is a rather intriguing idea. Personally, I love the idea of having an easily accessible math expression evaluator built into the language. However, Val historically has never parsed expressions. Doing this now, would be a breaking change. Perhaps we can expand Val like n = Val("3 * 3", -1), where the second optional argument would tell Val to enable the parser. No promises. Just thinking out loud. 

[SMcNeill]

It's not going to print 9 for you, as VAL doesn't do the math inside a string for you.  All it does is take the string you give it -- starting from the left and moving right 1 character at a time, until it comes across an unexpected character, and then returns the value of that leading string up to that point to you.

address$ =  "230 McNeil Hill Rd"
PRINT "Steve's house number is"; VAL(address$)

^ With the above, it's just going to print:  "Steve's house number is 230"  -- Everything after those numeric characters just get truncated and ignored.

So with your PRINT VAL("3 * 3"), it reads the leading 3.  Says, "Yep!  That's a number!".  Reads the spaced afterwards.  Says, "Nope!  Not a number!  The answer is 3!"

[SMcNeill]

This is a rather intriguing idea. Personally, I love the idea of having an easily accessible math expression evaluator built into the language. However, Val historically have never parsed expressions. Doing this now, would be a breaking change. Perhaps we can expand Val like n = Val("3 * 3", -1), where the second optional argument would tell Val to enable the parser. No promises. Just thinking out loud. 

Personally, I think this would be a terrible idea.  Basically, you'd be moving the math evaluator which we use for CONST and applying it to Val... and I can hear the complaints already!!  "Why isn't this command implemented?  Why can't I do VAL ("3 * INSTR(x$, "foo")")?  Or VAL("(ASC("B")")?  OR....

I predict nightmares for whoever is going to try to implement such.  

Instead, we should consider having a Resources folder, include the math evaluator in it, and then folks can just:

Code: (Select All)

PRINT Math$("3 * 3")
'$INCLUDE:'./Resources/math_eval.bas'

[PhilOfPerth]

Yep, got it,thanks.
As usual I mised a line or two of Help that explained all of this pretty well!
But I liked Steve's idea of a Math$ function that would allow a similar result to what I wanted!

[SMcNeill]

Yep, got it,thanks.
As usual I mised a line or two of Help that explained all of this pretty well!
But I liked Steve's idea of a Math$ function that would allow a similar result to what I wanted!

Just plug it in!   https://qb64phoenix.com/forum/showthread.php?tid=1266

[a740g]

This is a rather intriguing idea. Personally, I love the idea of having an easily accessible math expression evaluator built into the language. However, Val historically have never parsed expressions. Doing this now, would be a breaking change. Perhaps we can expand Val like n = Val("3 * 3", -1), where the second optional argument would tell Val to enable the parser. No promises. Just thinking out loud. 

Personally, I think this would be a terrible idea.  Basically, you'd be moving the math evaluator which we use for CONST and applying it to Val... and I can hear the complaints already!!  "Why isn't this command implemented?  Why can't I do VAL ("3 * INSTR(x$, "foo")")?  Or VAL("(ASC("B")")?  OR....

I predict nightmares for whoever is going to try to implement such.  

Instead, we should consider having a Resources folder, include the math evaluator in it, and then folks can just:

Code: (Select All)

PRINT Math$("3 * 3")
'$INCLUDE:'./Resources/math_eval.bas'

Now that you've said that... Yeah. The scope creep could be a disaster. This is best left to 3rd party libs.

[euklides]

"3 * 3" is an alphanumeric expression !

Val ("3 * 3") ---> 3
Val ("5 * 2") ---> 5
Val ("8 hundred dollars") ---> 8

In some old basic, this function existed: calculating an alphanumeric expression... 
X=Calculate("4 * 8")---> 32

But not here in qb64

[SMcNeill]

"3 * 3" is an alphanumeric expression !

Val ("3 * 3") ---> 3
Val ("5 * 2") ---> 5
Val ("8 hundred dollars") ---> 8

In some old basic, this function existed: calculating an alphanumeric expression... 
X=Calculate("4 * 8")---> 32

But not here in qb64

It is...  You just have to insert it yourself into your code: https://qb64phoenix.com/forum/showthread.php?tid=1266

[JRace]

"3 * 3" is an alphanumeric expression !

Val ("3 * 3") ---> 3
Val ("5 * 2") ---> 5
Val ("8 hundred dollars") ---> 8

In some old basic, this function existed: calculating an alphanumeric expression... 
X=Calculate("4 * 8")---> 32

But not here in qb64

That old Basic was probably interpreted.  Interpreters have various evaluation functions built-in for internal use.  Many interpreters are nothing but glorified evaluation functions.

With a compiled language, expressions must either be resolvable during compilation or resolved one step at a time using program code, unless you have a separate evaluation engine ala Steve's built into your program.


(Greenspun's tenth rule of programming: Any sufficiently complicated C or Fortran program contains an ad hoc, informally-specified, bug-ridden, slow implementation of half of Common Lisp.)
(In the modern day, this can be expanded to any sufficiently large program, involving any language(s).)