Another formatting question: function types

[Bill Venners-3]

Hi All,

I wanted to take the community's temperature on how they prefer to see
function types formatted. I have three questions.

1. Do you want spaces around the => or not? Here is with spaces:

(String, Int) => Unit

Here is without:

(String, Int)=>Unit

2. If a type has arity 1, do you want parens around it or not? Here it
is with parens:

(String) => Unit

Here it is without:

String => Unit

3. Lastly, anything else you like to see?

Thanks.

Bill
----
Bill Venners
Artima, Inc.
http://www.artima.com

[nuttycom]

1: With the spaces
2: Either is legible, without the spaces is cleaner.

On Wed, Jun 10, 2009 at 12:56 PM, Bill Venners<bill@...> wrote:

> Hi All,
>
> I wanted to take the community's temperature on how they prefer to see
> function types formatted. I have three questions.
>
> 1. Do you want spaces around the => or not? Here is with spaces:
>
> (String, Int) => Unit
>
> Here is without:
>
> (String, Int)=>Unit
>
> 2. If a type has arity 1, do you want parens around it or not? Here it
> is with parens:
>
> (String) => Unit
>
> Here it is without:
>
> String => Unit
>
> 3. Lastly, anything else you like to see?
>
> Thanks.
>
> Bill
> ----
> Bill Venners
> Artima, Inc.
> http://www.artima.com
>

[Geoff Reedy]

I've been writing

On Wed, Jun 10, 2009 at 11:56:35AM -0700, Bill Venners said
> 1. Do you want spaces around the => or not? Here is with spaces:
>
> (String, Int) => Unit

this

> Here it is without:
>
> String => Unit

and this

> 3. Lastly, anything else you like to see?

Prerences for by-name parameters too:

=>Foo

vs

=> Foo

Curiously I have a slight preference for no space here, even though I
use one for other function types.

>
> Thanks.
>
> Bill
> ----
> Bill Venners
> Artima, Inc.
> http://www.artima.com

[Grey]

Spaces and Parens.

Spaces for legibility.
Parens, cause I think of them as tuples, its an SML thing.

() 0-tuple
(String) 1-tuple
(String, Int) 2-tuple

On Wed, Jun 10, 2009 at 2:56 PM, Bill Venners <bill@...> wrote:

Hi All,

I wanted to take the community's temperature on how they prefer to see
function types formatted. I have three questions.

1. Do you want spaces around the => or not? Here is with spaces:

(String, Int) => Unit

Here is without:

(String, Int)=>Unit

2. If a type has arity 1, do you want parens around it or not? Here it
is with parens:

(String) => Unit

Here it is without:

String => Unit

3. Lastly, anything else you like to see?

Thanks.

Bill
----
Bill Venners
Artima, Inc.
http://www.artima.com

[Daniel Sobral]

Spaces and parens too. It might get weird if the result is a tuple of the same arity as the function, but...

On Wed, Jun 10, 2009 at 3:56 PM, Bill Venners <bill@...> wrote:

Hi All,

I wanted to take the community's temperature on how they prefer to see
function types formatted. I have three questions.

1. Do you want spaces around the => or not? Here is with spaces:

(String, Int) => Unit

Here is without:

(String, Int)=>Unit

2. If a type has arity 1, do you want parens around it or not? Here it
is with parens:

(String) => Unit

Here it is without:

String => Unit

3. Lastly, anything else you like to see?

Thanks.

Bill
----
Bill Venners
Artima, Inc.
http://www.artima.com

--
Daniel C. Sobral

Something I learned in academia: there are three kinds of academic reviews: review by name, review by reference and review by value.

[Daniel Spiewak]

1. Without spaces
2. Without parens

For example:

String=>Unit
(String, Int)=>Unit

I think this makes it a little cleaner without taking up too much space.  Also, I think it makes type annotations a bit easier to read.  For example:

val foo: String=>Unit = ...

vs.

val foo: String => Unit = ...

The extra spaces require a little more effort to parse (at least to my eye).  Rather than relying on spacing to delineate value, type and expression, I have to actually look at "=>" vs "=", symbols which have comparatively little visual distinction.

As a matter of interest, when programming Haskell or SML, I do prefer the spaces syntax:

-- Haskell
foldl :: (b -> a -> b) -> b -> List a -> b

(* SML *)
fun foldl f : (('b, 'a) -> 'b) init : 'b ls : ('a list) = ...

I'm not quite sure why I find the spaces better in Haskell/SML and not in Scala, but there it is.

Daniel

Bill Venners-3 wrote:

Hi All,

I wanted to take the community's temperature on how they prefer to see
function types formatted. I have three questions.

1. Do you want spaces around the => or not? Here is with spaces:

(String, Int) => Unit

Here is without:

(String, Int)=>Unit

2. If a type has arity 1, do you want parens around it or not? Here it
is with parens:

(String) => Unit

Here it is without:

String => Unit

3. Lastly, anything else you like to see?

Thanks.

Bill
----
Bill Venners
Artima, Inc.
http://www.artima.com

[Daniel Spiewak]

Correction, that should have been:

fun foldl f : (('b * 'a) -> 'b) init : 'b ls : ('a list) = ...

...for all five of you who care.  :-)

Daniel


1. Without spaces
2. Without parens

For example:

String=>Unit
(String, Int)=>Unit

I think this makes it a little cleaner without taking up too much space.  Also, I think it makes type annotations a bit easier to read.  For example:

val foo: String=>Unit = ...

vs.

val foo: String => Unit = ...

The extra spaces require a little more effort to parse (at least to my eye).  Rather than relying on spacing to delineate value, type and expression, I have to actually look at "=>" vs "=", symbols which have comparatively little visual distinction.

As a matter of interest, when programming Haskell or SML, I do prefer the spaces syntax:

-- Haskell
foldl :: (b -> a -> b) -> b -> List a -> b

(* SML *)
fun foldl f : (('b, 'a) -> 'b) init : 'b ls : ('a list) = ...

I'm not quite sure why I find the spaces better in Haskell/SML and not in Scala, but there it is.

Daniel

Bill Venners-3 wrote:

Hi All,

I wanted to take the community's temperature on how they prefer to see
function types formatted. I have three questions.

1. Do you want spaces around the => or not? Here is with spaces:

(String, Int) => Unit

Here is without:

(String, Int)=>Unit

2. If a type has arity 1, do you want parens around it or not? Here it
is with parens:

(String) => Unit

Here it is without:

String => Unit

3. Lastly, anything else you like to see?

Thanks.

Bill
----
Bill Venners
Artima, Inc.
http://www.artima.com

[Blair Zajac]

1. With spaces.
2. Without parens.
3. We need to figure out keyword and default argument formatting.  The Python
style guide PEP-8 has no spaces around default arguments.

http://www.python.org/dev/peps/pep-0008/

     - Don't use spaces around the '=' sign when used to indicate a
       keyword argument or a default parameter value.

       Yes:

           def complex(real, imag=0.0):
               return magic(r=real, i=imag)

       No:

           def complex(real, imag = 0.0):
               return magic(r = real, i = imag)

Blair

Bill Venners wrote:

> Hi All,
>
> I wanted to take the community's temperature on how they prefer to see
> function types formatted. I have three questions.
>
> 1. Do you want spaces around the => or not? Here is with spaces:
>
> (String, Int) => Unit
>
> Here is without:
>
> (String, Int)=>Unit
>
> 2. If a type has arity 1, do you want parens around it or not? Here it
> is with parens:
>
> (String) => Unit
>
> Here it is without:
>
> String => Unit
>
> 3. Lastly, anything else you like to see?
>
> Thanks.
>
> Bill
> ----
> Bill Venners
> Artima, Inc.
> http://www.artima.com
>