while with formatted (string interpolation) print reboots or hangs on Arduino UNO R3

[mobluse]

I installed Snek 1.7 on two Arduino UNO R3 boards. One original and one clone, but they give the same bug regarding the example with while from the tutorial in the documentation at https://sneklang.org/doc/snek.html#_while.

Welcome to Snek 1.7
> eeprom.show()
> eeprom.erase()
> def f_to_c(F):
+     return (5/9) * (F - 32)
+ 
> f_to_c(38)
3.3333335
> def f_to_c_table():
+   F = 0
+   while F < 100:
+     C = f_to_c(F)                                                                               
+     print('%f F = %f C' % (F, C))                                                               
+     F = F + 10                                                                                  
+                                                                                                 
> f_to_c_table()                                                                                  
0.000000 F = -17.777779 C                                                                         
10.000000 F = -12.222223 C                                                                        
20.000000 F = -6.666667 C                                                                         
30.000000 F = -1.111111 C                                                                         
40.000000 F = 4.444445 C                                                                          
50.000000 F = 10.000000 C                                                                         
60.000000 F = 15.555556 C                                                                         
70.000000 F = 21.111113 C                                                                         
Welcome to Snek 1.7                                                                               
> 

The output stops after 70 F, and the Arduino UNO R3 is reset by itself. Sometimes it hangs and Ctrl+C doesn't work. I believe this is related to the formatted print since it works if I replace it with print(F, C). The for example works even though that also uses print with string interpolation.

Flashing went without problems using a Raspberry Pi 4 B 8 GB with Raspberry Pi OS (Raspbian GNU/Linux 10 (buster)): /home/pi/.local/share/arduino-1.8.16/hardware/tools/avr/bin/avrdude -C/home/pi/.local/share/arduino-1.8.16/hardware/tools/avr/etc/avrdude.conf -v -patmega328p -carduino -P/dev/ttyACM0 -b115200 -D -Uflash:w:/home/pi/Downloads/snek/snek-uno-1.7.hex:i

I started with Snek only a few hours ago.

[keith-packard]

Looks like this example causes a C stack overflow, crashing the interpreter. I've tested a version with a smaller Snek heap, which leaves more space for the stack, and things work fine. See if this works for you!

snek-uno-1.7.zip

[mobluse]

When I connect to the Arduino UNO R3 with minicom -D /dev/ttyACM0 or press the reset button it shows:

<stdin>:51 out of memory
> 

And not Welcome to Snek... It does show Welcome to Snek 1.7 briefly, but then the screen is deleted and the error message is shown instead.

In snekde I get (since it seems to remove Esc):

> Welcome to Snek 1.7
[2J[H<stdin>:51 out of memory
> 

The while example works now, but it's not so nice to be greeted with an error message.

I tried both this version and one that I compiled myself, but get the same result.

Flashing went without problems for both hex-files.

[mobluse]

eeprom.erase() fixed the issue with out of memory on reset. There must have been some garbage there.