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I'm trying to do some morse code, but I'm struggling to work out the start position of the 'dit' and the 'dah'... I think first, the code...
id=1;wt=1; // for a ring, don't worry about these
lu = 1; // letter unit. a dit is 1 unit wide, a dah is 3, and the gap between them is 1.
module drawChar(s) {
echo("char: ", s);
pos = 0;
for(i = [0:len(s)-1]) {
inc = 0;
if(s[i] == ".") {
echo(s[i], "dit ",pos," ", inc);
translate([pos+lu/2,0,0]) cylinder(r=lu/2, h = (id+wt+2)/2);
inc = (1 + 1)*lu;
} else if(s[i] == "-") {
echo(s[i], "dah ",pos," ", inc);
translate([pos,-lu/2,0]) cube([3*lu,lu,(id+wt+2)/2]);
inc = (3+1)*lu;
}
pos = pos + inc; // the inc seems to have gone out of scope
}
}
drawChar("--.-"); // this is a 'q'
This is the output:
ECHO: "char: ", "--.-"
ECHO: "-", "dah ", 0, " ", 4
ECHO: "-", "dah ", 0, " ", 4
ECHO: ".", "dit ", 0, " ", 2
ECHO: "-", "dah ", 0, " ", 4
I have tried many ways to calculate 'pos' - the starting point of the dit/dah. So the bit that's getting me is the way assignments seem to work - basically pos always stays zero. Also at the point of echoing inc, I'm expecting it to still be zero.
2 questions I suppose, a learning point for me, what's going on? and second, how do I make it do what I want it to do?
I was thinking of some way to count the occurances of '.' and '-' in the array as a function multiplying accordingly, but my brain melted a little - it is early.
Any help much appreciated
Nigel
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For info, here is my recursive position counter that fails:
function cpos(s, n) = cpos(s,n-1) + (n == -1) ? (0) : ( (s[n]==".") ? 2 : 4);
when I use it instead of pos in the x coordinate for example in the dit:
translate([cpos(s,i)+lu/2,0,0]) cylinder(r=lu/2, h = (id+wt+2)/2);
it says recursion detected. It's not lying  but the manual says I can do recursion with the trigraph stuff.
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This post was updated on .
Doh!!! yep.
I moved the conditional calling, but this is still not playing nicely:
function cpos(s, n) = (n == -1) ? (0) : ( cpos(s,n-1) + (s[n]==".") ? 2 : 4 );
echo ("--.-, 0: ", cpos("--.-",0));
echo ("--.-, 1: ", cpos("--.-",1));
echo ("--.-, 2: ", cpos("--.-",2));
echo ("--.-, 3: ", cpos("--.-",3));
ECHO: "--.-, 0: ", 4
ECHO: "--.-, 1: ", 4
ECHO: "--.-, 2: ", 4
ECHO: "--.-, 3: ", 4
I have also noticed a problem in that 0 should be 0 which I'll fix later, but that aside, I would expect the following
ECHO: "--.-, 0: ", 4
ECHO: "--.-, 1: ", 8
ECHO: "--.-, 2: ", 10
ECHO: "--.-, 3: ", 14
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Sorry, yep, I'm using the latest release 2015.03 on both mac and windows
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Yep, I'm now using recursion to bypass that :) but it seems I'm a bit rusty at that as well.
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pos = pos + inc; // the inc seems to have gone out of scope
This is the problem: this is the last definition for pos, so only this one is used (pos=0 will be ignored). And it is undefined, as when the left side is assigned the right side has no meaning,yet. Its a recursion.
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Yeah I'm not doing that any more because it doesn't work. I've moved to recursion. Possibly an email lag?
This is what is now not working:
function cpos(s, n) = (n == -1) ? (0) : ( cpos(s,n-1) + (s[n]==".") ? 2 : 4 );
cpos("--.-",3) returns 4, instead of 14.
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function cpos(s, n) = (n == -1) ? (0) : ( cpos(s,n-1) + (s[n]==".") ? 2 : 4 );
// run through expected results from cpos ("--.-", 3):
s = "--.-";
echo (s[0]=="."? 2 : 4); // Outputs "ECHO: 4" - CORRECT
echo (s[1]=="."? 2 : 4); // Outputs "ECHO: 4" - CORRECT
echo (s[2]=="."? 2 : 4); // Outputs "ECHO: 2" - CORRECT
echo (s[3]=="."? 2 : 4); // Outputs "ECHO: 4" - CORRECT
echo ( 0 // n = -1
+ s[0]=="."?2:4 // n = 0 so should be 4
+ s[1]=="."?2:4 // n = 1 so should be 4
+ s[2]=="."?2:4 // n = 2 so should be 2
+ s[3]=="."?2:4 // n = 3 so should be 4
); // Outputs "ECHO: 4" - should be 0 + 4 + 4 + 2 + 4 = 14
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Administrator
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BTW you may want to check out assign() [depricated] and this.
Admin - email* me if you need anything,
or if I've done something stupid...
* click on my MichaelAtOz label, there is a link to email me.
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And there's the answer - brackets :)
function cpos(s, n) = (n == 0) ? (0) : ( cpos(s,n-1) + ((s[n-1]==".") ? 2 : 4 ));
Now works as expected.
Thanks guys!!!
N.
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I'm usually an avid bracketer for readability and avoidance of doubt. This one beat me  Thanks again.
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