external variables

Hello Dxl Community,,

I attach two small files which I wrote for doing a basic unit test of the concept of combining callback functions and eval_ to do the following

(1) Run the main function (main.dxl) in the DXL editor window

(2) This invokes the code written in #"include D:\\WORKAREA\ImportFunction.dxl"

(3) The main Boolean variable "b_main" is assigned to bSocSuccessFlag, which is assigned a value TRUE or FALSE depending on whether the user pressed apply_cb1 or apply_cb2.

The problem is that although the function ImportFunction.dxl was executed in the line

eval_(dxlCode), we do not retain the variable "bSocSuccessFlag" which was locally defined there.

I would like that bSocSuccessFlag could be accessed like an extern variable like in C.

However if I run Supplier Import I get

E DXL: <Line:6> undeclared variable (bSocSuccessFlag)

E DXL: <Line:6> incorrect arguments for (=)

I DXL: All done. Errors reported: 2. Warnings reported: 0.

How can I make it extern? or how can produce the same effect?

Colm

MyDeveloerWorks - Wed Jun 28 03:26:54 EDT 2017

Re: external variables
Mathias Mamsch - Wed Jun 28 07:03:58 EDT 2017

First: your include statement is wrong. it should be:

#include <D:/WORKAREA/ImportFunction.dxl>

Apart from that you can use the "return_" perm to return a string from eval. For simply returning a boolean value I would use this.

string evalCode = "
#include <myscript>
if (bSocSuccessFlag) return_ \"OK\";
"
string s = eval_ evalCode
if (s == "OK") print "yey ;-)"

Another technique is to try to put a reference inside the eval_ script and write that reference from the eval.

boolean myVar = false; 

string evalCode = "
bool &bReference =  addr_ " ((addr_ (&myVar))int) " 
#include <myscript>
bReference = bSocSuccessFlag
"

eval_ evalCode

print "Yey: " myVar "\n"

The above code will work only on 32bit. For 64 bit you need to refer to the corresponding posts on the forum (search for eval_ 64 mathias). Hope this helps, regards, Mathias

Re: external variables
MyDeveloerWorks - Thu Jun 29 05:11:18 EDT 2017

Mathias Mamsch - Wed Jun 28 07:03:58 EDT 2017

First: your include statement is wrong. it should be:

#include <D:/WORKAREA/ImportFunction.dxl>

Apart from that you can use the "return_" perm to return a string from eval. For simply returning a boolean value I would use this.

string evalCode = "
#include <myscript>
if (bSocSuccessFlag) return_ \"OK\";
"
string s = eval_ evalCode
if (s == "OK") print "yey ;-)"

Another technique is to try to put a reference inside the eval_ script and write that reference from the eval.

boolean myVar = false; 

string evalCode = "
bool &bReference =  addr_ " ((addr_ (&myVar))int) " 
#include <myscript>
bReference = bSocSuccessFlag
"

eval_ evalCode

print "Yey: " myVar "\n"

The above code will work only on 32bit. For 64 bit you need to refer to the corresponding posts on the forum (search for eval_ 64 mathias). Hope this helps, regards, Mathias

Hello Mathias,,

Thanks for the very valuable hints and corrections. Both suggestions work well.

(.... Actually I should always use the DXL lib folder so I can do a <myscript> instead of absolute paths to D: !

I slapped myself on the wrist for that. I promise not to do it again!)

Colm