scala semicolon inference example - scala

Question

The "Programming in scala" introduces the rules of semicolon inference:
In short, a line ending is treated as a semicolon unless one of the following conditions is true:
The line in question ends in a word that would not be legal as the end of a statement, such as a period or an infix operator.
The next line begins with a word that cannot start a statement.
The line ends while inside parentheses(...) or brackets[...], because these cannot contain multiple statements anyway.
But I can't find an example that in the second condition,who can give an example?
I have tried the following code because * cannot start a statement,but it failed!
1 * 2
*3

Answer 1

The "Programming in scala" introduces the rules of semicolon inference:
In short, a line ending is treated as a semicolon unless one of the following conditions is true:
The line in question ends in a word that would not be legal as the end of a statement, such as a period or an infix operator.
The next line begins with a word that cannot start a statement.
The line ends while inside parentheses(...) or brackets[...], because these cannot contain multiple statements anyway.
Note that this is a rather simplified view. The full rules are in section 1.2 Newline Characters of the Scala Language Specification.
But I can't find an example that in the second condition,who can give an example?
According to the SLS:
The tokens that can begin a statement are all Scala tokens except the following delimiters and reserved words:
catch
else
extends
finally
forSome
match
with
yield
,
.
;
:
=
=>
<-
<:
<%
>:
#
[
)
]
}
So, one example could be:
return 42
.toString()
This is equivalent to
return 42.toString(); // returns the `String` "42"
and not
return 42; // returns the `Int` 42
.toString() // dead code
I have tried the following code because * cannot start a statement,but it failed!
1 * 2
*3
What makes you think that * cannot start a statement? Please, re-read the spec carefully. A method call is perfectly legal starting a statement:
foo(bar)
is valid, and so is
*(3)
Ergo, * can start a statement. Full example:
object Test
def test = {
1 * 2
*(3)
}
def *(x: Int) = {
println(x)
x + 1
}
}
Test.test
// 3
//=> res0: Int = 4