topic Re: Multiple nested IF-THEN commands to simulate AND/OR in GDL

Multiple nested IF-THEN commands to simulate AND/OR

Jim Allen — Thu, 26 Sep 2024 11:27:45 GMT

Just when I think I've got the hang of these, I get a really complicated one I can't seem to fix.

GDL has no IFS or AND/OR/NOT options, so every condition has to be covered with a separate if statement.

I can make this work - up to a point. More than a couple of combinations and my script fails.

I want to script something like:

If option 1 is true, then if option 2 is also true - do x, but if option 1 is true and option 2 is not true - do y.

What almost worked is this:

if detailOpt_2D_1=1 then ! if draw chamber selected AND if detailOpt_2D=1 then ! if draw outer wall also selected AND if drawConnectors=1 then ui_pict "GDL_UI_2d_4_1", 240, 60, 210, 190, 1 ! if connectors also selected -> ui picture: cover + chamber + wall + connectors **works** else if drawConnectors=0 then ui_pict "GDL_UI_2d_4", 240, 60, 210, 190, 1 ! if connectors not selected -> ui picture: cover + chamber + wall **doesn't work** if detailOpt_2D=0 then ! OR if draw outer wall not selected if drawConnectors=1 then ui_pict "GDL_UI_2d_2_1", 240, 60, 210, 190, 1 ! if connectors also selected -> ui picture: cover + chamber with connectors **works** if drawConnectors=0 then ui_pict "GDL_UI_2d_2", 240, 60, 210, 190, 1 ! if connectors not selected -> ui picture: cover + chamber **works** endif endif endif if detailOpt_2D_1=0 then ! if draw chamber not selected AND if detailOpt_2D=1 then ! if draw outer wall selected AND if drawConnectors=1 then ui_pict "GDL_UI_2d_3_1", 240, 60, 210, 190, 1 ! if connectors selected -> ui picture: cover + wall + connectors **works** else if drawConnectors=0 then ui_pict "GDL_UI_2d_3", 240, 60, 210, 190, 1 ! if connectors not selected -> ui picture: cover + wall **doesn't work** if detailOpt_2D=0 then ! OR if draw wall not selected if drawConnectors=1 then ui_pict "GDL_UI_2d_1_1", 240, 60, 210, 190, 1 ! if connectors also selected -> ui picture: cover + connectors **works** if drawConnectors=0 then ui_pict "GDL_UI_2d_1", 240, 60, 210, 190, 1 ! if connectors not selected -> ui picture: cover **works** endif endif endif

You'll need to paste this into a document with a wider display to see the structure properly.

This is what the dialog looks like:

I want to display different UI pictures in the interface depending on a combination of user options.

The ELSE lines are screwing it up - everything else seems to work.

I've tried breaking it down into distinct separate lines, but the combinations of options are problematic.

I've been wrestling with this for hours now and everything I do to it just makes it worse!

What am I doing wrong?

Re: Multiple nested IF-THEN commands to simulate AND/OR

Miha Nahtigal — Tue, 09 Jan 2024 17:48:48 GMT

What do you mean by "GDL has no IFS or AND/OR/NOT options"?

GDL does have AND, OR and NOT structure (not() is a function).

Re: Multiple nested IF-THEN commands to simulate AND/OR

Jim Allen — Tue, 09 Jan 2024 18:23:21 GMT

Really?

For some reason I haven't seen that in the reference, and I've looked at a lot of documentation about - thanks!

Re: Multiple nested IF-THEN commands to simulate AND/OR

MF BIM — Tue, 09 Jan 2024 19:22:53 GMT

Hi @Jim Allen ,

Why not use some kind of bitset ? Seems like you don't have that many options and they all are boolean so you can just create boolean variables that you set at 0 or 1 then you calculate the overall score and according to that total, you display what you need ?

Option_A = 1 Option_B = 1 Option_C = 0 Option_D = 0 SCORE = Option_A + Option_B*2 + Option_C*4 + Option_D*8 if SCORE = 0 then ui_pict if SCORE = 1 then ui_pict ! ... if SCORE = 15 then ui_pict

Probably more verbose but it's likely cleaner at the end than many IF with AND or OR

You could even use the BITSET function even though in my opinion, the syntax of that function makes it more complicated than flat out using boolean variables.

SCORE = 0 dim my_list[4] my_list[1] = 1 ! true my_list[2] = 1 ! true my_list[3] = 0 ! false my_list[4] = 0 ! false for option = 1 to vardim1(my_list) SCORE = bitset(SCORE, option - 1, my_list[option]) next option if SCORE = 0 then ui_pict if SCORE = 1 then ui_pict ! ... if SCORE = 15 then ui_pict

Re: Multiple nested IF-THEN commands to simulate AND/OR

Lingwisyer — Wed, 10 Jan 2024 02:13:46 GMT

Why is the ELSE even there? Your description of the IF statement following it says that it should include "Wall", but it since it is after the ELSE, it only queries when detailOp_2D is 0... This also makes the "IF detailOpt_2d = 0" redundant, unless it is more than just a boolean?

if detailOpt_2D_1=1 then ! Chamber if detailOpt_2D=1 then ! Wall if drawConnectors=1 then ui_pict "GDL_UI_2d_4_1", 240, 60, 210, 190, 1 ! Connector if drawConnectors=0 then ui_pict "GDL_UI_2d_4", 240, 60, 210, 190, 1 ! No Connector else ! No Wall if drawConnectors=1 then ui_pict "GDL_UI_2d_2_1", 240, 60, 210, 190, 1 ! Connector if drawConnectors=0 then ui_pict "GDL_UI_2d_2", 240, 60, 210, 190, 1 ! No Connector endif endif if detailOpt_2D_1=0 then ! No Chamber if detailOpt_2D=1 then ! Wall if drawConnectors=1 then ui_pict "GDL_UI_2d_3_1", 240, 60, 210, 190, 1 ! Connector if drawConnectors=0 then ui_pict "GDL_UI_2d_3", 240, 60, 210, 190, 1 ! No Connector else ! No Wall if drawConnectors=1 then ui_pict "GDL_UI_2d_1_1", 240, 60, 210, 190, 1 ! Connector if drawConnectors=0 then ui_pict "GDL_UI_2d_1", 240, 60, 210, 190, 1 ! No Connector endif endif

Ling.

Re: Multiple nested IF-THEN commands to simulate AND/OR

Jim Allen — Wed, 10 Jan 2024 12:52:43 GMT

I know it seems to make no sense, but if I take it out, more things break!

I've never seen any documentation anywhere mentioning using AND/OR in flow control statements, but they work really well and I think are a great solution to complex flow control statements.

I made it work properly using this:

! --------------- select UI picture based on dialog options ----------------------- if detailOpt_2D_1=0 AND detailOpt_2D=1 AND drawConnectors=1 then ui_pict "GDL_UI_2d_3_1", 240, 60, 210, 190, 1 if detailOpt_2D_1=0 AND detailOpt_2D=1 AND drawConnectors=0 then ui_pict "GDL_UI_2d_3", 240, 60, 210, 190, 1 if detailOpt_2D_1=0 AND detailOpt_2D=0 AND drawConnectors=1 then ui_pict "GDL_UI_2d_1_1", 240, 60, 210, 190, 1 if detailOpt_2D_1=0 AND detailOpt_2D=0 AND drawConnectors=0 then ui_pict "GDL_UI_2d_1", 240, 60, 210, 190, 1 if detailOpt_2D_1=1 AND detailOpt_2D=1 AND drawConnectors=1 then ui_pict "GDL_UI_2d_4_1", 240, 60, 210, 190, 1 if detailOpt_2D_1=1 AND detailOpt_2D=1 AND drawConnectors=0 then ui_pict "GDL_UI_2d", 240, 60, 210, 190, 1 if detailOpt_2D_1=1 AND detailOpt_2D=0 AND drawConnectors=1 then ui_pict "GDL_UI_2d_2_1", 240, 60, 210, 190, 1 if detailOpt_2D_1=1 AND detailOpt_2D=0 AND drawConnectors=0 then ui_pict "GDL_UI_2d_2", 240, 60, 210, 190, 1

It's so much easier to read and script - much, much cleaner, and works perfectly.

Elsewhere I was able to replace this:

if ZZYZX<0.901 then if max(numBranches, numBranches2)=3 then ! if depth>0.9 AND 3 branches on 1 side ChamberLength=1.03 else ! otherwise if if max(numBranches, numBranches2)>3 then ! there are >3 branches on any side ChamberLength=1.37 else ChamberLength= 0.8 endif endif endif

with this:

if ZZYZX<0.901 AND max(numBranches, numBranches2)<3 then ChamberLength=0.8 if ZZYZX<0.901 AND max(numBranches, numBranches2)=3 then ChamberLength=1.03 if ZZYZX<0.901 AND max(numBranches, numBranches2)>3 then ChamberLength=1.37 if ZZYZX>0.9 AND max(numBranches, numBranches2)<4 then ChamberLength=1.25 if ZZYZX>0.9 AND max(numBranches, numBranches2)>3 then ChamberLength=1.37

Which works much better.

However I really like MF BIM's bitset approach - I might be using that for my next object 😀

Re: Multiple nested IF-THEN commands to simulate AND/OR

Jim Allen — Wed, 10 Jan 2024 14:31:30 GMT

That's a really interesting approach I hadn't thought of - thanks!

Re: Multiple nested IF-THEN commands to simulate AND/OR

Peter Baksa — Tue, 23 Jan 2024 03:11:03 GMT

Hi,

if-else is not as flexible in GDL as in other languages.

There are two kind of if statements: single-line and multi-line.

Multi-line if must have this form (newlines are important, indentation is not):

if condition then
   statement
[else
   statement]
endif

When statement is on the same line as if, it is considered a single-line if, and the else might belong to an other if than you intended:

if condition1 then
    if condition2 then statement1
else ! this belongs to condition1 because the previous line is a one-line if, no matter how you indent this line
    statament2
endif