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Icon+Unicon/Intro: Difference between revisions
→Odds and Ends: semi-colons
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== Odds and Ends ==
This section is a catchall for a number of Odds and Ends. In some cases, the the only criteria for inclusion is that they may be found a bit odd and have no other logical home.
=== &fail considered harmful? ===
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end</lang>
As one can see this is less about the behavior of &fail as it is about the behavior of return and suspend.
=== Semi-colons ===
Unicon and Icon don't require you insert semi-colons as line terminators like some languages. Instead the compiler/translator detects the end of an expression and automatically inserts one for you. Two caveats, (1) you must insert them yourself if you wish to write multiple expressions in a line, and (2) if you split an expression across a line boundary at an operator you must leave the operator on the first line or your expression will be prematurely terminated. As follows:
<lang Icon> x := 1; y := 2; z:= -3 # 1st case
s3 := s1 ||
s2 # 2nd case - like this
s3 := s1
|| s2 # ... not this</lang>
The other place this comes up is writing one-liners. While not a recommended style, there are tasks that require it [[Narcissist]] and [[Quine]] are examples. Consider for example the following two programs:
<lang Icon>procedure main();sub();end;procedure sub();write("1st example");end</lang>
<lang Icon>procedure main();sub();end procedure sub();write("2nd example");end</lang>
It might seem natural at first to write the first example, however, no semi-colon is needed between and end and procedure declaration. The second case is correct and the first generates a compile error.
= Run Time Considerations =
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