Hi, im new to ruby. I ve qaquestions about closures
1) if i defiene this
def loopN n, &b
i=0
while (i<n) do
b.call
i+=1
end
end
Why the first and the second calls dosnt works and the third works?
1.1) loopN 5, {puts "hola"} # compile error , parse error unexpected
"{", expected "$"
1.2) loopN 5 {puts "hola"} # compile error , unexpected tString.
1.2) loopN (5) {puts "hola"} # works
thanks
Hi,
Am Donnerstag, 15. Feb 2007, 20:52:08 +0900 schrieb Pedro Del Gallego:
Why the first and the second calls dosnt works and the third works?
1.1) loopN 5, {puts "hola"} # compile error , parse error unexpected
"{", expected "$"
1.2) loopN 5 {puts "hola"} # compile error , unexpected tString.
1.2) loopN (5) {puts "hola"} # works
Precedence. "do .. end" has low precedence, applies to the leftmost
function name, "{ ..}" has high.
loopN 5 do puts "hola" end # should work
Bertram
--
Bertram Scharpf
Stuttgart, Deutschland/Germany
http://www.bertram-scharpf.de
Why the first and the second calls dosnt works and the third works?
1.1) loopN 5, {puts "hola"} # compile error , parse error unexpected
"{", expected "$"
Ruby doesn't expect a comma between the last standard argument and
the optional block argument. Drop the comma.
1.2) loopN 5 {puts "hola"} # compile error , unexpected tString.
The {} of the block is binding to the number 5, which is a syntax error.
You need to add parens to clarify your intent as in:
1.2) loopN (5) {puts "hola"} # works
This would be more commonly written as:
loopN(5) { puts "hola"}
Alternatively you can use do/end, which has low precedence
loopN 5 do
puts "hola"
end
Gary Wright
On Feb 15, 2007, at 6:52 AM, Pedro Del Gallego wrote: