Simple script inside Eval strings

[ErosOlmi]

Maybe not all of you know about the possibility of Eval module to evaluate little scripts more complex than a math or string expressions.
Here a little dummy script just to give you an idea.

The script check if a string variable has a "0" inside it. If yes reports it and parse 3rd token.

 uses "EVAL"
 uses "CONSOLE"
 
 '---Some timing variable
 dim t0, t1 as double = timer
 
 '---This string containing the script to be executed
 dim MyString as string = "
       '---DIM AUTO will automatically dimension new variables when found
       dim AUTO
       '---No need to DIM the variable if DIM AUTO is in place
       '---If variable ends with a $ it is string, otherwise numeric (EXT)
       Info_GotIt$ = "" <--- Got it.""

       '---Add a "GOT IT" message every time "0" is found inside the main string
       IF instr(InternalScriptStringVariable, ""0"") then
        InternalScriptStringVariable = InternalScriptStringVariable & Info_GotIt$
        InternalScriptStringVariable = InternalScriptStringVariable & "" Number is: "" & parse$(InternalScriptStringVariable, chr$(32), 3)
       END IF
       "
 '---Used to get back results from Eval
 dim sResult as string

 '---Define a looper and its max
 dim Count   as long
 dim MaxCount as long value 500

 for Count = 1 to MaxCount

  '---Set InternalScriptStringVariable variable and value
  Eval_SetString("InternalScriptStringVariable", "Looper is " & Count)

  '---Eval_String will evaluate MyString and will return result
  Eval(MyString)

  '---Get back the value of the internal variable after script has modified it.
  sResult = Eval_GetString("InternalScriptStringVariable")

  '---Write some info output
  printl format$(Count, "0000") & " - Eval_String returned: " & sResult

 next 

 '---Measure the ending time
 t1 = timer

 '---Final results  
 printl "------------------------------------------------------"
 printl "Total execution time for " & MaxCount & " loops: " & format$(t1-t0, "#0.00000")

 '---Stop execution
 waitkey

[Petr Schreiber]

And you say this "by the way"

That is pretty cool!
I presume "little script" is defined as script using just CORE keywords and no functions?


Thanks,
Petr

[kryton9]

Thanks for the demo Eros. There are lots of gems like this that are unknown I know to me. Posts like this and articles in the new journal will hope to bring these to light!

[ErosOlmi]

I presume "little script" is defined as script using just CORE keywords and no functions?

Not exacly but very close.
EVAL is an interpreter inside the main thinBasic interpreter but supported functionalities in EVAL are not the same as in Core in the sense that even if keywords in EVAL use the same syntax as the Core, it is not the same engine.

EVAL supports very few set of keywords but anyhow quite sufficient to write little scripts.
I will update EVAL help file. I need time >