OpenEuphoria

Re: Variable substitution

• Posted by Mike <vulcan at w?n.co?nz> Dec 12, 2007
• 558 views

Mike777 wrote:
> 
> I have read a few threads on variable substitution, but they all seem to
> predate
> v3.1.1.  Has the ability been added?  If not, is there a common way to
> implement
> it? 
> 
> I'm trying to develop of database driven windowing system.  That means I read
> from my database the information I need in order to build windows and widgets.
> 
> A simple example might be that I go to the database to find that I want to
> build
> a combo box and that the name of the combo box should be "Combo1".
> 
> If I was positioning the combo myself in the IDE, it might generate the
> following:
> 
> global constant Combo1 = createEx( Combo, "", Window1, 432, 76, 588, 28*6,
> PBS_VERTICAL+LBS_NOINTEGRALHEIGHT,
> 0 )
> 
> After I read the database, I have two variables, say TYPEOFWIDGETTOBUILD,
> which
> has the value "Combo" and NUMBEROFWIDGETTOBUILD, which has the value "1"
> 
> Is there any way to write something like:
> 
> global constant &TYPEOFCOMOBOTOBUILD&NAMEOFWIDGETTOBUILD = createEx( Combo,
> "", Window1, 432, 76, 588, 28*6, PBS_VERTICAL+LBS_NOINTEGRALHEIGHT, 0 )
> 
> If that can't be done, can somebody suggest a workaround?
> 
> Thanks
> 
> Mike


What you seem to be trying to do will entail building a file that contains the
correct text.
You need to output a text string having the desired values. Eg,

sequence text

text = "global constant " & TYPEOFCOMOBOTOBUILD&NUMBEROFWIDGETTOBUILD

This (as you know) evaluates to "global constant Combo1"

You can use a function like sprintf() to format certain values (such as control
dimensions etc..), eg:

constant
  height = 100,
  width = 200

text = sprintf( "Window, %d, %d" {width, height})

..becomes "Window, 200, 100"

Another example:

text = sprintf( 
  "global constant %s%s = create( %s, \"\", Window1, %d, %d)",
{TYPEOFCOMOBOTOBUILD, NUMBEROFWIDGETTOBUILD, TYPEOFCOMOBOTOBUILD, width,
  height} )

text is now "global constant Combo1 = create( Combo, "", Window1, 200, 100)"

And then there is printf() which is the same as sprintf() but also outputs the
string to a file.
If you create the text string separately you can use puts() to output it to a
file, eg:

puts(file_id, text)

Dont forget the line terminator, eg:

puts(file_id, text & '\n')

HTH,
Mike