Why is the following returning an error?
[1, 2, 3, 4].each( { |num| puts num } )
Why is this not equivalent to:
[1, 2, 3, 4].each { |num| puts num }
What am I missing here about the 'everything is a method' hence should follow the same pattern and parantheses can be omitted if there is no ambiguity methodology?
Because that's syntactically invalid. That isn't a supported syntax for passing a block to a method.
Ruby's syntax allows for one special block argument to each method, apart from the regular arguments. The argument is defined differently (via the { |args| ... } syntax) and (optionally) accepted differently through a final &variable parameter:
def my_method(arg1, arg2, &block)
block.call("ok1")
# or, a special syntax for calling the &block:
yield "ok!"
end
my_method(value_for_arg_1, value_for_arg_2) do |arg|
# when invoked by my_method, arg will be "ok!"
end
You can pass the block as part of the argument list, but again, a specific syntax is required:
my_block = Proc.new { puts "I'm a proc" }
my_method(value1, value2, &my_block)
The above &my_block is required only if you intend to pass the proc through as the &block parameter; you can pass an arbitrary number of procs through without using &, but they aren't callable via yield.
Hash syntax is not as per the Ruby Hash syntax, so the error popped up. It is not due to the valid block IMHO
if x in C++ instead of if (x): It's not valid syntax.Because a block is not an object. An argument must be an object. You cannot replace an argument with a block or vice versa. You cannot enclose a block within parentheses and treat it like an argument.
Because if you pass block into method (like in this case), you put it outside parantheses, even if you use them for other arguments.
