view 2-Io/day2-loops.io @ 77:7bab4843aec6

Add roulette with auto-restarting process (And black-magic auto-registering of atoms)
author IBBoard <dev@ibboard.co.uk>
date Sat, 03 Feb 2018 20:42:51 +0000
parents 86668d32e162
children
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# loop() gives an infinite loop - let's not run that!

# While loops aren't too unfamiliar:
#     while(condition, code)
# where calls can be put in a "block" with semicolons
i := 1
# Notice the lack of "++"
while(i <= 11, i println; i = i + 1); "This one goes up to 11" println
"Or we could have put the line here" println

# For loops are similarly simple:
#    for(variable, min, max, code)
for(i, 1, 11, i println); "For this one also goes up to 11" println

# Oddly (but necessarily) the increment is in the middle of that as an optional parameter
increment := 2
for(i, 1, 11, increment, i println); "For this one goes to 11 in 2s" println

# This is bad in some cases, because Io accepts extra args without complaining
# BUT it'll fill in extra args first
# AND things have potentially unexpected return values (e.g. "11 println" returns 11)
# Although it's actually just returning *something* so that you can chain more methods
# and in many cases then "self" is the best return, e.g. "11 println println" prints twice
for (i, 1, 10, 2, i println, "extra arg gets ignored")
"Bad arg example" println
for (i, 1, 10, /* no increment arg, so command runs *and* becomes increment*/ i println, "extra arg becomes message")
# However, we apparently only see the last print! Seems odd and unexpected - unless we're taking it from the previous call?
for (j, 1, 10, /* no increment arg, so command runs *and* becomes increment*/ j println, "extra arg becomes message")
# Yep, this crashes out!