Possibly handy VBS script

[Dias de verano]

Win2K onwards...

Code: [Select]

Wscript.echo eval(WScript.Arguments(0))
Save this script as Evaluate.vbs

Now, (cumbersome) either call it by

cscript //nologo "Path to\evaluate.vbs" "valid VBS expression" [quotes not always needed but advised]

Code: [Select]

C:\>cscript //nologo "c:\utils\evaluate.vbs" "hour(time)"
10

C:\>cscript //nologo "c:\utils\evaluate.vbs" "2/3"
0.666666666666667

C:\>cscript //nologo "c:\utils\evaluate.vbs" "time"
10:17:54

C:\>cscript //nologo "c:\utils\evaluate.vbs" "now"
21/02/2009 10:18:00
or...

(less cumbersome to use)

1. Save it somewhere on your PATH, with a name that does not duplicate any existing executable on your PATH.

2. Set cscript as the default vbs engine by executing cscript //H:cscript

3. Turn off the logo display by executing cscript //nologo /S

(These settings are saved and will persist through reboots until you alter them as described in cscript /?)

Now you can do this

Code: [Select]

C:\>evaluate "1/9"
0.111111111111111

C:\>evaluate "(100/2)*3"
150

C:\>evaluate "100/(2*3)"
16.6666666666667

C:\>evaluate "2^16"
65536

C:\>evaluate "4*atn(1)"
3.14159265358979

C:\>evaluate now
21/02/2009 10:26:24

C:\>evaluate "(4*atn(1))*(5^2)"
78.5398163397448

and in a batch... (watch out for the ^ operator - use 1 at the prompt, 2 in a batch file)

Code: [Select]

@echo off
set radius=5
set pi=(4*atn(1))
set expression=%pi%*(%radius%^^2)
for /f "delims==" %%A in ('evaluate "%expression%" ') do set answer=%%A
set area=%answer%
echo Circle radius: %radius%
echo Circle area:   %area%


[macdad-]

nice script Dias,

does it also work with batch variables?

[Dias de verano]

nice script Dias,

does it also work with batch variables?

Not sure what you mean. You can feed batch variables into it. In a batch you could invoke it directly if you just wanted to show the answer or you could use FOR to get the answer into a batch variable. Above, I showed it evaluating a batch string variable like this:

Code: [Select]

set pi=(4*atn(1))
set expression=%pi%*(%radius%^^2)
for /f "delims==" %%A in ('evaluate "%expression%" ') do set answer=%%A
set area=%answer%
or...

Code: [Select]

C:\>set n1=6

C:\>set n2=5

C:\>evaluate %n1%+%n2%
11

[BatchFileCommand]

^ operator

What does the ^ operator do?

[BC_Programmer]

Exponentiation. I think it escapes characters in batch so I think that has something to do with it.


I still say BCScript and BASeParser are better. They can, after all, do this:

Code: [Select]

STORE(X,{25,36,49})
STORE(Y,Sqr(-X)+X[{1,2,3} PICK 1])
BCSH@WriteLn(Y)
which would output(possibly, given use of random PICK operator):

Code: [Select]

{5i+25,6i+49,7i+36}


Supports Imaginary numbers, as well as intrinsic support for matrix operations and so forth- not to mention such novel operators such as the "PICK" operator used previous as well as nCr and nPr (number of Combinations and Number of Permutations, respectively) And ** or ^ as multiplication, Logical and boolean operations, etc.

It's going to be a tough cookie to document, though...

And I assure you it's not one line of code. Actually:



15,080 code lines and 6,863 Comment lines.

So I suppose this method wins in the terseness department...

[macdad-]

nice script Dias,

does it also work with batch variables?

Not sure what you mean. You can feed batch variables into it. In a batch you could invoke it directly if you just wanted to show the answer or you could use FOR to get the answer into a batch variable. Above, I showed it evaluating a batch string variable like this:

Code: [Select]

set pi=(4*atn(1))
set expression=%pi%*(%radius%^^2)
for /f "delims==" %%A in ('evaluate "%expression%" ') do set answer=%%A
set area=%answer%
or...

Code: [Select]

C:\>set n1=6

C:\>set n2=5

C:\>evaluate %n1%+%n2%
11

thats what i meant...but its pretty good. 

[Dusty]

Really handy - floating point math in batch scripting is a step closer (almost).

Thanks Dias.

[Dias de verano]

Exponentiation. I think it escapes characters in batch so I think that has something to do with it.

And it also can act as a line continuation character, depending on the circumstances. So you can prettify batch scripts where the lines are very long.

Code: [Select]

@echo off
dir ^
/a-d ^
/w

But its role as a batch script control character means it needs escaping in a batch file, by the escape char which happens to be another ^ (caret) character. I have seen people call it a "carrot".

[BC_Programmer]

I've had people call it an up-arrow. Not exactly accurate, or the Asterisk, "I put my password in and I see a bunch of spiders"