Hello. I tried to avoid some parenthesis and have got some problems.
Firstly, I wanted to write this code in fashion of ternary operator:

perl -le '$_ = "a"; print do { if( length ){ "A" } else{ "B" } };'
[download]

OUTPUT:

A
[download]

There is with "ternary":

perl -le '$_ = "a"; print length ? "A" : "B" '
[download]

OUTPUT:

Warning: Use of "length" without parentheses is ambiguous at -e line 1
+.
Use of ?PATTERN? without explicit operator is deprecated at -e line 1.
Search pattern not terminated or ternary operator parsed as search pat
+tern at -e line 1.
[download]

I forgot that 'length' is unary operator with higher precedence, so it interpret following '?' as matching parens. Same if I would write: 'print length // "A" ' - error, when 'print length || "A" ' - is ok.
So I tried to avoid 'length' to interpret '?' as regex in this way:

perl -le '$_ = "a"; print length . '' ? "A" : "B" '
[download]

But it still outputs:

Use of ?PATTERN? without explicit operator is deprecated at -e line 1.
Search pattern not terminated or ternary operator parsed as search pat
+tern at -e line 1.
[download]

Concatenation point has higher precedence than unary 'length' so I think 'length' should give its value which will be concatenated with empty line, and later ternaty op., and later - 'print'.
If I use '+ 0' instead, I got warning of ambiguity (but '+' can't start a regex, and for me seems that there is no ambiguity):

perl -le '$_ = "a"; print length + 0 ? "A" : "B" '
[download]

Warning: Use of "length" without parentheses is ambiguous at -e line 1
+.
A
[download]

---

---

Posts are HTML formatted. Put <p> </p> tags around your paragraphs. Put <code> </code> tags around your code and data!

Titles consisting of a single word are discouraged, and in most cases are disallowed outright.

Read Where should I post X? if you're not absolutely sure you're posting in the right place.

Please read these before you post! —

• How do I compose an effective node title?
• How do I post a question effectively?
• Markup in the Monastery

Posts may use any of the Perl Monks Approved HTML tags:

a, abbr, b, big, blockquote, br, caption, center, col, colgroup, dd, del, details, div, dl, dt, em, font, h1, h2, h3, h4, h5, h6, hr, i, ins, li, ol, p, pre, readmore, small, span, spoiler, strike, strong, sub, summary, sup, table, tbody, td, tfoot, th, thead, tr, tt, u, ul, wbr

You may need to use entities for some characters, as follows. (Exception: Within code tags, you can put the characters literally.)

	For:		Use:
	&		&
	<		&lt;
	>		&gt;
	[		&#91;
	]		&#93;

Link using PerlMonks shortcuts! What shortcuts can I use for linking?

See Writeup Formatting Tips and other pages linked from there for more info.