Using "puts" in ternary operator

ruby-talk
1

I find that I get errors if I use "puts" in it's standard form in a
ternary operator
x == 2 ? puts "two" : puts "one"

error is:

SyntaxError: (irb):3: syntax error, unexpected tSTRING_BEG, expecting
keyword_do or '{' or '('
x == 2 ? puts "two" : puts "one"
               ^
(irb):3: syntax error, unexpected ':', expecting $end
x == 2 ? puts "two" : puts "one"
                     ^

It works however if I use this form:
x == 2 ? puts("two") : puts("one")
Could someone help me figure out why? Is there documentation somewhere
on this?

thanks

···

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Posted via http://www.ruby-forum.com/.

2

SyntaxError: (irb):3: syntax error, unexpected tSTRING_BEG, expecting
keyword_do or '{' or '('
x == 2 ? puts "two" : puts "one"
^
(irb):3: syntax error, unexpected ':', expecting $end
x == 2 ? puts "two" : puts "one"

I think the lack of parens creates an ambiguous scope for the
argument to the initial `puts` whereas your next form doesn't.

x == 2 ? puts("two") : puts("one")

Regardless you could DRY it up (without even parens) as

puts x == 2 ? "two" : "one"

FWIW,

···

On Fri, Jul 22, 2011 at 4:18 PM, Jesse Breuer <jesse.breuer@gmail.com> wrote:
--
Hassan Schroeder ------------------------ hassan.schroeder@gmail.com

twitter: @hassan

3

I find that I get errors if I use "puts" in it's standard form in a
ternary operator
x == 2 ? puts "two" : puts "one"

error is:

SyntaxError: (irb):3: syntax error, unexpected tSTRING_BEG, expecting
keyword_do or '{' or '('
x == 2 ? puts "two" : puts "one"
^
(irb):3: syntax error, unexpected ':', expecting $end
x == 2 ? puts "two" : puts "one"
^

imho,
ruby is trying to read it as:

x == 2 ? puts ("two" : puts "one")

it reads the puts first, but then it encounters the colon, so...

It works however if I use this form:
x == 2 ? puts("two") : puts("one")

or:
x == 2 ? (puts "two" ) : (puts "one" )

Could someone help me figure out why? Is there documentation somewhere
on this?

use parens to help the interpreter

kind regards -botp

···

On Sat, Jul 23, 2011 at 7:18 AM, Jesse Breuer <jesse.breuer@gmail.com> wrote:

4

A syntax for a tenary operator is:

(exp)? <if true> : <if false>

<if true> and <if false> is always the one object - I think that ruby
can't tell whether you're trying to call puts or push two or more
elements in these "fields". So use the parenthesized form to call a
function.

PS. Sorry for my not technical language ;).

Yours,
Martin

···

2011/7/23 Jesse Breuer <jesse.breuer@gmail.com>:

I find that I get errors if I use "puts" in it's standard form in a
ternary operator
x == 2 ? puts "two" : puts "one"

error is:

SyntaxError: (irb):3: syntax error, unexpected tSTRING_BEG, expecting
keyword_do or '{' or '('
x == 2 ? puts "two" : puts "one"
^
(irb):3: syntax error, unexpected ':', expecting $end
x == 2 ? puts "two" : puts "one"
^

It works however if I use this form:
x == 2 ? puts("two") : puts("one")
Could someone help me figure out why? Is there documentation somewhere
on this?

thanks

--
Posted via http://www.ruby-forum.com/\.

5

puts x == 2 ? "two" : "one"

···

On Jul 22, 2011, at 16:18 , Jesse Breuer wrote:

It works however if I use this form:
x == 2 ? puts("two") : puts("one")