[gathering-options] Arrow symbol

[Rémi Forax]

On 06/24/2011 04:20 AM, Ola Bini wrote:
> Stephen
>
> I don't know if this is a valid thing to say based on your rules, but
> the pipe symbol is going to be quite hard to use for the first { }
> syntax, since it is ambiguous with the binary or operator. That
> ambiguity should be possible to resolve from a semantic perspective,
> since a lambda taking one argument will always be assigned to a SAM with
> one argument type, but I assume that such semantic resolution will
> happen way after parsing time.
>
> Cheers

Hi Ola,
you are right, there is an ambiguity if there is no prefix symbol like '#'
in front of the curly braces.

And mixing the parsing and the semantics resolution is not in Java gene.

Rémi

> On 2011-06-23 14.55, Stephen Colebourne wrote:
>> Summary after 1 day of "gathering options":
>>
>> (I've added more examples, using what I believe to be reasonable
>> variants of two syntax families, please don't argue too much based on
>> the rest of the syntax I used, just focus on the "arrow")
>> ----------------------------------------
>> Standard single line examples:
>> Use ->
>>    {x ->  x + 1}
>>    (x) ->  {x + 1}
>>
>> Use =>
>>    {x =>  x + 1}
>>    (x) =>  {x + 1}
>>
>> Use :
>>    {x : x + 1}
>>    (x) : {x + 1}
>>
>> Use |
>>    {x | x + 1}
>>    (x) | {x + 1}
>>
>> ----------------------------------------
>> Alternate single line examples:
>> Use ->
>>    { ->  42}
>>    {x ->  {y ->  x + y}}
>>
>>    () ->  {42}
>>    x ->  {y ->  {x + y}}
>>    x ->  y ->  x + y
>>
>> Use =>
>>    { =>  42}
>>    {x =>  {y =>  x + y}}
>>
>>    () =>  {42}
>>    x =>  {y =>  {x + y}}
>>    x =>  y =>  x + y
>>
>> Use :
>>    { : 42}
>>    {x : {y : x + y}}
>>
>>    () : {42}
>>    x : {y : {x + y}}
>>    x : y : x + y
>>
>> Use |
>>    { | 42}
>>    {x | {y | x + y}}
>>
>>    () | {42}
>>    x | {y | {x + y}}
>>    x | y | x + y
>>
>> ----------------------------------------
>> Multi-line examples:
>> Use ->
>>    {x, y ->
>>      if (x>  y) {
>>        return x;
>>      }
>>      return y;
>>    }
>>
>> Use =>
>>    {x, y =>
>>      if (x>  y) {
>>        return x;
>>      }
>>      return y;
>>    }
>>
>> Use :
>>    {x, y :
>>      if (x>  y) {
>>        return x;
>>      }
>>      return y;
>>    }
>>
>> Use |
>>    {x, y |
>>      if (x>  y) {
>>        return x;
>>      }
>>      return y;
>>    }
>>
>> ----------------------------------------
>> - This thread is for GATHERING OPTIONS, not voting or discussing.
>> - You should only suggest an option if you personally prefer it to the
>> ->  or =>  symbol
>> - You MUST include the two (original) examples converted to use your
>> preferred symbol
>> - Suggesting a symbol does not imply that you want any syntax with an
>> arrow (ie. you can prefer strawman family, but suggest an arrow
>> symbol)
>> - Don't reply just to say "I don't want an arrow symbol"
>> - Don't reply to propose a syntax that is completely different to one
>> of the four syntax families
>>
>> This is the *final call* for arrow proposals.
>>
>> Stephen
>>
>>
>