From: furufuru@... (Ryo Furue)
Date: 2001-08-07T21:25:06+09:00
Subject: [ruby-talk:19283] Help with ternary operator syntax and grammar

Hi there,

I'm fairly new to Ruby and writing small scripts with the pickaxe
book.  I can't understand what's wrong with this:

	cond = true
	print (cond? ", " : "\n")

which gives you a "parse error" at line 2.  The following gives you
the same error (first line elided):

	print cond? ", " : "\n"

Also, this

	print (cond)? ", " : "\n"

prints "true", not ", ".  What's going on?  Yet, the following prints
what you expect (a comma followed by a blank)

	print ((cond)? ", " : "\n")

Aha, I got it, what I needed were the parentheses around the whole
expression!  BUT, the following gives you the parse error again

	print (cond == true? ", " : "\n")

OK, I see, I need both pairs of parentheses. *BUT*, the following
program works!

	cond = 1
	print (cond == 1? ", " : "\n")

I'm clueless.  Could someone enlighten me by explaining the underlying
rules?

By the way, I like Ruby very much.  As soon as I came to know it, I
abandoned Perl.

Cheers,
Ryo