Syntax error with blocks

O

Oliver Sauders

OK guys, wtf am I doing wrong here?
The manual says I should be able to do this.

=======================

irb(main):150:0> { puts 'foo' }
SyntaxError: compile error
(irb):150: syntax error, unexpected tSTRING_BEG, expecting kDO or '{' or
'('
{ puts 'foo' }
^
(irb):150: syntax error, unexpected '}', expecting $end
from (irb):150
from :0
irb(main):151:0> { puts('foo') }
SyntaxError: compile error
(irb):151: odd number list for Hash
from (irb):151
from :0
irb(main):158:0> do puts 'foo' end
SyntaxError: compile error
(irb):158: syntax error, unexpected kDO
do puts 'foo' end
^
(irb):158: syntax error, unexpected kEND, expecting $end
from (irb):158
from :0
irb(main):160:0> do; puts 'foo'; end
SyntaxError: compile error
(irb):160: syntax error, unexpected kDO
do; puts 'foo'; end
^
(irb):160: syntax error, unexpected kEND, expecting $end
from (irb):160
from :0
 
B

Banzai

OK guys, wtf am I doing wrong here?
The manual says I should be able to do this.

=======================

irb(main):150:0> { puts 'foo' }
SyntaxError: compile error
(irb):150: syntax error, unexpected tSTRING_BEG, expecting kDO or '{' or
'('
{ puts 'foo' }
^
(irb):150: syntax error, unexpected '}', expecting $end
from (irb):150
from :0
irb(main):151:0> { puts('foo') }
SyntaxError: compile error
(irb):151: odd number list for Hash
from (irb):151
from :0
irb(main):158:0> do puts 'foo' end
SyntaxError: compile error
(irb):158: syntax error, unexpected kDO
do puts 'foo' end
^
(irb):158: syntax error, unexpected kEND, expecting $end
from (irb):158
from :0
irb(main):160:0> do; puts 'foo'; end
SyntaxError: compile error
(irb):160: syntax error, unexpected kDO
do; puts 'foo'; end
^
(irb):160: syntax error, unexpected kEND, expecting $end
from (irb):160
from :0

A code block is not a valid statement. If you want to create a Proc
object, use lambda.

irb(main):001:0> x = lambda { puts 'foo' }
=> #<Proc:0x0035393c@(irb):1>
irb(main):002:0> x.call
foo
=> nil
 
E

Eric I.

The other thing to keep in mind is that blocks are parameters passed
into methods, so they're always associated with a method call. For
example:

10.times { puts 'foo' }

The block is a parameter to the times method that is being called on
the Integer 10.

Even in Banzai's example:

x = lambda { puts 'foo' }

The block is passed to a method named lambda that returns a Proc of
the block passed in.

Eric
 
O

ole __

Cool. I'm guessing something like this:

1.times { puts 'foo' }

or

lamba { puts 'foo' }.call

is never really used but could be used to achieve block scope.
 
C

CHubas

Cool. I'm guessing something like this:

1.times { puts 'foo' }

or

lamba { puts 'foo' }.call

is never really used but could be used to achieve block scope.


If you want a more block like behavior, use begin/end

begin
puts 'Hello from block'
end
 

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