hash-style parameters

[Terry Michaels]

Some function calls I've seen, like in Shoes, look like so:

para "Paragraph Text", :style => "this", :whatever => "that"

How do I define a function call so that can take one "normal" parameter
and then an unknown number of key/value pairs?

 

[David Masover]

Some function calls I've seen, like in Shoes, look like so:

para "Paragraph Text", :style => "this", :whatever => "that"

How do I define a function call so that can take one "normal" parameter
and then an unknown number of key/value pairs?

You could answer your own question by looking at the source of the program
doing this -- and I'd suggest it for anything you want to learn more about.

For this case, remember that this basically becomes:

para("Paragraph Text", {:style => "this", :whatever => "that"})

And of course, there's no reason those literals need to be there -- you could
just do this:

text = "Paragraph Text"
hash = {:style => "this", :whatever => "that"}
para(text, hash)

So, it should be clear that this is what you want:

def para text, options

There is one catch, though -- you said "unknown number", which could be zero,
so you need a default value:

def para text, options={}

 

[Pablo Torres N.]

So, it should be clear that this is what you want:

def para text, options

There is one catch, though -- you said "unknown number", which could be zero,
so you need a default value:

def para text, options={}

Just a note: while you can omit parens in method definitions, most
code does only if the method takes no arguments, if it does, leave the
parens there.

 

[David Masover]

Just a note: while you can omit parens in method definitions, most
code does only if the method takes no arguments, if it does, leave the
parens there.

Why?

I find it more readable without parens, but with syntax highlighting, mostly
because that's how I call methods.

 

[Pablo Torres N.]

Why?

I find it more readable without parens, but with syntax highlighting, mostly
because that's how I call methods.

Just a convention, I guess precisely so you can easily tell method
definitions and method invocations apart. Consider:

def say_hi(tittle, name)
puts "Hi, #{tittle} #{name}"
end

tittle = "Dr."
name = "Cham"

some_obj.instance_eval do
def say_hi tittle, name
puts "Howdy, #{tittle} #{name}"
end
end

A bit ambiguous.

 

[Roger Pack]

def para text, options

There is one catch, though -- you said "unknown number", which could be
zero,
so you need a default value:

def para text, options={}

There is also the "named parameter" gem which might be useful to you:
http://github.com/rdp/arguments