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Macro and global scope question — Gideros Forum
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    Macro and global scope question

    perrochonperrochon Member
    in Bugs and issues
    It's not critical, but I wonder why I get an error message (attempt to call global 'print' (a nil value)' in the editor on the code below. I am using print inside a macro. The code runs fine (in the Windows player).

    The error message shows up after the second line of the file (no matter what's in the first two lines). It refers the print in the second line of the macro (line ~10). If I comment out that print, there is no error, i.e. the print further down outside the macro don't trigger.

    It looks like
    - the syntax check in the editor doesn't fully understand macros and global scope.
    - displays that error message offset to beginning of file, instead of macro (i.e. if print is on line 5 in the macro, error goes on line 5 of the code)

    The same behavior happens when I use table (as described here: https://wiki.giderosmobile.com/index.php/Macro_Functions )


    --distance function
function distance(o1, o2)
	return math.sqrt((o1.c - o2.c)*(o1.c - o2.c) + (o1.r - o2.r)*(o1.r - o2.r))
end
 
--distance macro
-- Note: comma counts as arguments. If called with comma separated arguments, the second one has index 3
--          (...)[3]
DISTANCE @ (|
	print("math.sqrt((" .. (...)[1] .. ".c - " .. (...)[3] .. ".c) *  (" .. (...)[1] .. ".c - " .. (...)[3] .. ".c) + "
		        ..   "(" .. (...)[1] .. ".r - " .. (...)[3] .. ".r) * (" .. (...)[1] .. ".r - " .. (...)[3] .. ".r))" )
	return "math.sqrt((" .. (...)[1] .. ".c - " .. (...)[3] .. ".c) * ( " .. (...)[1] .. ".c - " .. (...)[3] .. ".c) + "
		        ..   "(" .. (...)[1] .. ".r - " .. (...)[3] .. ".r) * (" .. (...)[1] .. ".r - " .. (...)[3] .. ".r))"
|)
 
-- test data
local o1, o2, o3, zero = {c = -1, r = 1}, {c = 3, r = 4}, {c = -9, r = -9}, {c = 0, r = 0}
 
print(distance(o1, o2), distance(o1, zero), distance(o2, zero), distance(o3, zero))
print(DISTANCE(o1, o2), DISTANCE(o1, zero), DISTANCE(o2, zero), DISTANCE(o3, zero))
    Also, it took me a while to figure out how to do a macro that returns an expression (i.e. single line, without declaring local variables in the macro. Should we add a code snipped to the page above?
    SUM @ (| return "("..(...)[1] + (...)[3] ..")" |)
print (SUM(1,2) * SUM(3,1))
    I am using (...)[1] to refer to the first argument directly, and (...)[3] to the second so I can invoke the macro with comma-separated parameters. Commas count as arguments, i.e. DISTANCE(o1, o2) has three parameters. I think the behavior makes sense once you think of it, but it wasn't obvious.

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    Comments

    • MoKaLuxMoKaLux Member
      please note some words may be reserved, so it is better to name your macros with really fancy names, for example instead of DISTANCE name it MYDISTANCE (or whatever but not DISTANCE), the same for SUM name it MYSUM (or whatever but not SUM).
      Hope this helps resolve your issue!?
      my growING GIDEROS github repositories: https://github.com/mokalux?tab=repositories
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    • perrochonperrochon Member
      @MoKaLux thanks for the quick answer (as usual). I renamed the functions, but it doesn't change the editor behavior




      RenamedFunctions.JPG
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    • MoKaLuxMoKaLux Member
      I have tested your code in latest gideros and it doesn't show the warning even with live syntax on. Are u using zerobrane?

      Also I have added your example to the wiki. Please tell me if it's correct.

      I haven't used macros a lot :/
      my growING GIDEROS github repositories: https://github.com/mokalux?tab=repositories
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    • rrraptorrrraptor Member
      edited June 2020
      Seems like something wrong with live syntax :D

      The code is working.

      Also, I dont like when you have a lot of concatenations. So I did this:
      DISTANCE @ (|
	print( ("math.sqrt((%s.c - %s.c) *  (%s.c - %s.c) + (%s.r - %s.r) * (%s.r - %s.r))"):format(
		(...)[1], (...)[3], (...)[1], (...)[3], (...)[1], (...)[3], (...)[1], (...)[3])
	)
	return ("math.sqrt((%s.c - %s.c) * ( %s.c - %s.c) + (%s.r - %s.r) * (%s.r - %s.r))"):format(
		(...)[1], (...)[3], (...)[1], (...)[3], (...)[1], (...)[3], (...)[1], (...)[3])
|)
      h.png
      587 x 712 - 28K

      Likes: perrochon

      h.png 28.3K
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    • hgy29hgy29 Maintainer
      I don’t know how macro code works, but it looks like the parser tries to execute code, which it shouldn’t
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    • perrochonperrochon Member
      MoKaLux said:

      Also I have added your example to the wiki. Please tell me if it's correct.

      Thanks. Looks like my code. You suggested calling it MYSUM. The Wiki seems to have a different account from the Forum, correct? Do I just create another account there so I can update it myself?
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    • perrochonperrochon Member
      rrraptor said:



      Also, I dont like when you have a lot of concatenations. So I did this:

      DISTANCE @ (|
	print( ("math.sqrt((%s.c - %s.c) *  (%s.c - %s.c) + (%s.r - %s.r) * (%s.r - %s.r))"):format(
		(...)[1], (...)[3], (...)[1], (...)[3], (...)[1], (...)[3], (...)[1], (...)[3])
	)
	return ("math.sqrt((%s.c - %s.c) * ( %s.c - %s.c) + (%s.r - %s.r) * (%s.r - %s.r))"):format(
		(...)[1], (...)[3], (...)[1], (...)[3], (...)[1], (...)[3], (...)[1], (...)[3])
|)
      Nice, this is a lot more readable.

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    • MoKaLuxMoKaLux Member
      oh :)
      you can ask sinistersoft to give you access.
      my growING GIDEROS github repositories: https://github.com/mokalux?tab=repositories
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    • SinisterSoftSinisterSoft Maintainer
      @MoKaLux Done. :)

      Likes: MoKaLux

      Coder, video game industry veteran (since the '80s, ❤'s assembler), arrested - never convicted hacker (in the '90s), dad of five, he/him (if that even matters!).
      https://deluxepixel.com
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