G'day Bod,

I thought we'd broken your habit of omitting the strict and warnings pragmata. Perhaps not. :-(

Whenever checking out short pieces of Perl code, I typically use this alias:

$ alias perle
alias perle='perl -Mstrict -Mwarnings -Mautodie=:all -MCarp::Always -E
+'
[download]

[Sorry, I don't know the best way to implement that using MSWin. I'm sure another monk can advise you on that if needs be.]

$ perle 'print (localtime)[6];'
print (...) interpreted as function at -e line 1.
syntax error at -e line 1, near ")["
Execution of -e aborted due to compilation errors.
 at -e line 1.
[download]

You can get more information from perldiag:

%s (...) interpreted as function

(W syntax) You've run afoul of the rule that says that any list operator followed by parentheses turns into a function, with all the list operators arguments found inside the parentheses. See "Terms and List Operators (Leftward)" in perlop.

That information may be too terse; or you may have difficulty locating it due to the presence of formats (e.g. %s in this case). Either, or both, of those situations may be resolved by using the diagnostics pragma:

$ perle 'use diagnostics; print (localtime)[6];'
print (...) interpreted as function at -e line 1 (#1)
    (W syntax) You've run afoul of the rule that says that any list op
+erator
    followed by parentheses turns into a function, with all the list
    operators arguments found inside the parentheses.  See
    "Terms and List Operators (Leftward)" in perlop.

print (...) interpreted as function at -e line 1.
syntax error at -e line 1, near ")["
Execution of -e aborted due to compilation errors (#2)
    (F) Probably means you had a syntax error.  Common reasons include
+:

        A keyword is misspelled.
        A semicolon is missing.
        A comma is missing.
        An opening or closing parenthesis is missing.
        An opening or closing brace is missing.
        A closing quote is missing.

    Often there will be another error message associated with the synt
+ax
    error giving more information.  (Sometimes it helps to turn on -w.
+)
    The error message itself often tells you where it was in the line 
+when
    it decided to give up.  Sometimes the actual error is several toke
+ns
    before this, because Perl is good at understanding random input.
    Occasionally the line number may be misleading, and once in a blue
+ moon
    the only way to figure out what's triggering the error is to call
    perl -c repeatedly, chopping away half the program each time to se
+e
    if the error went away.  Sort of the cybernetic version of 20 ques
+tions.

syntax error at -e line 1, near ")["
Execution of -e aborted due to compilation errors.
 at -e line 1.
[download]

Although you can rewrite your code:

$ perle 'my $wday = (localtime)[6]; print $wday;'
6
[download]

The quickest fix is to simply follow the function with a no-op unary plus before the left parenthesis:

$ perle 'print +(localtime)[6];'
6
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See perlop: Symbolic Unary Operators:

...
Unary "+" has no effect whatsoever, even on strings. It is useful syntactically for separating a function name from a parenthesized expression that would otherwise be interpreted as the complete list of function arguments. ...
...