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37
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1 # loop() gives an infinite loop - let's not run that!
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2
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3 # While loops aren't too unfamiliar:
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4 # while(condition, code)
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5 # where calls can be put in a "block" with semicolons
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6 i := 1
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7 # Notice the lack of "++"
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8 while(i <= 11, i println; i = i + 1); "This one goes up to 11" println
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9 "Or we could have put the line here" println
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10
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11 # For loops are similarly simple:
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12 # for(variable, min, max, code)
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13 for(i, 1, 11, i println); "For this one also goes up to 11" println
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14
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15 # Oddly (but necessarily) the increment is in the middle of that as an optional parameter
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16 increment := 2
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17 for(i, 1, 11, increment, i println); "For this one goes to 11 in 2s" println
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18
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19 # This is bad in some cases, because Io accepts extra args without complaining
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20 # BUT it'll fill in extra args first
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21 # AND things have potentially unexpected return values (e.g. "11 println" returns 11)
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22 # Although it's actually just returning *something* so that you can chain more methods
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23 # and in many cases then "self" is the best return, e.g. "11 println println" prints twice
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24 for (i, 1, 10, 2, i println, "extra arg gets ignored")
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25 "Bad arg example" println
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26 for (i, 1, 10, /* no increment arg, so command runs *and* becomes increment*/ i println, "extra arg becomes message")
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27 # However, we apparently only see the last print! Seems odd and unexpected - unless we're taking it from the previous call?
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28 for (j, 1, 10, /* no increment arg, so command runs *and* becomes increment*/ j println, "extra arg becomes message")
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29 # Yep, this crashes out!
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30
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