Eval: Difference between revisions

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== Description ==
== Description ==


Eval returns a value created by executing an expression as if it were a FUNCTION procedure. The required parameter, ''string'', is a string expression that is executed. If multiple statements are to be executed, separate them with a carriage return (vbCRLF). The temporary, virtual procedure that gets created has all program variables passed in by value, so the variables are unmodifiable by the Eval function.
Eval returns a value created by executing an expression as if it were a Function procedure. The required parameter, ''string'', is a string expression that is executed. If multiple statements are to be executed, separate them with a carriage return (vbCRLF). The temporary, virtual procedure that gets created has all program variables passed in by value, so the variables are unmodifiable by the Eval function.


The code in the string is evaluated as JavaScript code. See the TechNote “Using JavaScript with NS Basic/X Programs”.
The code in the string is evaluated as JavaScript code. See the TechNote 04 “The role of JavaScript, HTML5 and WebKit”.


== Example ==
== Example ==


<pre>
<tabber>
REM Eval Example
JavaScript=
'Eval execute a string as a FUNCTION
<syntaxhighlight lang="JavaScript">
// Eval Example
/* Eval execute a string as a Function */
 
var x;
x = 5;
NSB.Print(eval("x"));
eval("x = x * 10");
NSB.Print(x);</syntaxhighlight>
|-|
BASIC=
<syntaxhighlight lang="vb.net">
Rem Eval Example
'Eval execute a string as a Function
Dim x
Dim x
x = 5
x = 5
PRINT Eval("x")
Print Eval("x")
Eval("x = x * 10")
Eval("x = x * 10")
PRINT x
Print x
</pre>
</syntaxhighlight>
</tabber>


== Output ==
== Output ==
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<pre>
<pre>
5
5
5
50
</pre>
</pre>


== Related Items ==
== Related Items ==


[[execute|EXECUTE]]
[[execute|Execute]]


[[Category:Language Reference]]
[[Category:Language Reference]]
[[Category:Strings]]

Latest revision as of 17:45, 22 July 2019

Eval(string)

Description

Eval returns a value created by executing an expression as if it were a Function procedure. The required parameter, string, is a string expression that is executed. If multiple statements are to be executed, separate them with a carriage return (vbCRLF). The temporary, virtual procedure that gets created has all program variables passed in by value, so the variables are unmodifiable by the Eval function.

The code in the string is evaluated as JavaScript code. See the TechNote 04 “The role of JavaScript, HTML5 and WebKit”.

Example

// Eval Example
/* Eval execute a string as a Function */

var x;
x = 5;
NSB.Print(eval("x"));
eval("x = x * 10");
NSB.Print(x);

Rem Eval Example
'Eval execute a string as a Function
Dim x
x = 5
Print Eval("x")
Eval("x = x * 10")
Print x

Output

5
50

Related Items

Execute