Should "new" methods do anything?

[Philip Mak]

A programming style question:

Should "new" methods actually do anything, or should they only perform
initialization?

For example, let's say I have a class called "Httpd" which runs an
HTTP server. Should its interface be like this:

server = Httpd.newlisten_port => 80) # Initialize the server
server.run # Run it

Or like this?

Httpd.newlisten_port => 80) # Initialize and run the server

The latter way is more streamlined, but feels bad for some reason that
I can't quite put into words right now.

 

[Aredridel]

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A programming style question:
=20
Should "new" methods actually do anything, or should they only perform
initialization?
=20
For example, let's say I have a class called "Httpd" which runs an
HTTP server. Should its interface be like this:
=20
server =3D Httpd.newlisten_port =3D> 80) # Initialize the server
server.run # Run it
=20
Or like this?
=20
Httpd.newlisten_port =3D> 80) # Initialize and run the server

Let it return self.

Then:

Httpd.newlisten_port =3D> 80).run

=20
The latter way is more streamlined, but feels bad for some reason that
I can't quite put into words right now.

Well, perhaps you want to wait to run until you've checked some
things...


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[Sean O'Dell]

A programming style question:

Should "new" methods actually do anything, or should they only perform
initialization?

For example, let's say I have a class called "Httpd" which runs an
HTTP server. Should its interface be like this:

server = Httpd.newlisten_port => 80) # Initialize the server
server.run # Run it

Or like this?

Httpd.newlisten_port => 80) # Initialize and run the server

The latter way is more streamlined, but feels bad for some reason that
I can't quite put into words right now.

I don't think it will cause any harm to your program, but to me it's
non-intuitive as to what "new" does. I don't think many people would
expect that simply creating the server also launches it.

In those cases, I usually make a class method to combine the
functionality, i.e.:

server = Httpd::launch_serverlisten_port => 80)

.... and keep the class like this:

class Httpd
def initialize(listen_port)
# init only
end

def run
# launch the server
end

Httpd::launch_server(listen_port)
server = Https.newlisten_port = listen_port)
server.run
return server
end
end


Sean O'Dell

 

[Simon Strandgaard]

A programming style question:

Should "new" methods actually do anything, or should they only perform
initialization?

[snip]

server = Httpd::launch_serverlisten_port => 80) [snip]

Httpd::launch_server(listen_port)
server = Https.newlisten_port = listen_port)
server.run
return server
end

Yes, Factory methods is nice.. it can also look like this

Httpd.launch(options=nil)
Https.new(options).run
end

 

[Gavin Sinclair]

A programming style question:

Should "new" methods actually do anything, or should they only perform
initialization?

For example, let's say I have a class called "Httpd" which runs an
HTTP server. Should its interface be like this:

server = Httpd.newlisten_port => 80) # Initialize the server
server.run # Run it

Or like this?

Httpd.newlisten_port => 80) # Initialize and run the server

The latter way is more streamlined, but feels bad for some reason that
I can't quite put into words right now.

The method is "doing too much", a common problem. You may want to
pass the server to another method which runs it, or not, based on some
other things.

Gavin