Command of the Day: EVAL

[Walt Decker]

EVAL()?

EVAL$()?

[Walt Decker]

'
SS.LEFT             = HEXDEC("&H00000000")
SS.CENTER           = HEXDEC("&H00000001")
SS.RIGHT            = HEXDEC("&H00000002")
SS.SIMPLE           = HEXDEC("&H0000000B")
SS.NOPREFIX         = HEXDEC("&H00000080")
SS.NOTIFY           = HEXDEC("&H00000100")
SS.CENTERIMAGE      = HEXDEC("&H00000200")
SS.SUNKEN           = HEXDEC("&H00001000")

Style$ = "SS.CENTER,SS.CENTERIMAGE,SS.SUNKEN"

Value = 0
FOR I = 1 TO 3
 Value = Value OR EVAL(WORD$(Style$, I, ","))
NEXT I
'

Anyone else?

[gaslouk]

Happy new year.

I modified the Liberty basic help example a bit to see the result

 a$(0) = "zero 00"
 a$(1) = "one 11"
 a$(2) = "two 22"
 a$(3) = "three 33"
 a$(4) = "four 44"
 a$(5) = "five 55"
 a$(6) = "six 66"
 a$(7) = "seven 77"
 a$(8) = "eight 88"
 a$(9) = "nine 99"

 b$(0) = "0"
 b$(1) = "1"
 b$(2) = "2"
 b$(3) = "3"
 b$(4) = "4"
 b$(5) = "5"
 b$(6) = "6"
 b$(7) = "7"
 b$(8) = "8"
 b$(9) = "9"

 for i=0 to 9
 code$ = "a$(i)"
 code1$ = "b$(i)"
 print "We will evaluate the code: "; code$; code1$
 result$ = eval$(code$)
 result1$ = eval$(code1$)
 print result$, result1$
 'Now let's use the eval function, which effectively does a
 'val() to the result of the calculation. Converting a non
 'numeric string to a numeric value results in zero.
 result = eval(code$)
 result1 = eval(code1$)
 print result, result1
 next i



And here are the results.

We will evaluate the code: a$(i)b$(i)
zero00 0
0 0
We will evaluate the code: a$(i)b$(i)
one11 1
0 1
We will evaluate the code: a$(i)b$(i)
two22 2
0 2
We will evaluate the code: a$(i)b$(i)
three33 3
0 3
We will evaluate the code: a$(i)b$(i)
for44 4
0 4
We will evaluate the code: a$(i)b$(i)
five55 5
0 5
We will evaluate the code: a$(i)b$(i)
six66 6
0 6
We will evaluate the code: a$(i)b$(i)
seven77 7
0 7
We will evaluate the code: a$(i)b$(i)
eight88 8
0 8
We will evaluate the code: a$(i)b$(i)
nine99 9
0 9

Gaslouk

[Walt Decker]

I notice you are only using EVAL. What will the result be if you use both EVAL() and EVAL$()?

[gaslouk]

Jan 3, 2023 9:23:23 GMT -5 Walt Decker said:

I notice you are only using EVAL. What will the result be if you use both EVAL() and EVAL$()?

Both are in use Walt.

[Walt Decker]

I am sorry. I did not see the EVAL$() in the code, and the print out of the result did not make it obvious. I will pay more attention in the future.

Can you come up with something else using EVAL(), EVAL$(), perhaps branching to another routine based on the returned value?