A space used to be accepted between minus sign and number in old versions of Squeak compiler (before 2010)

But I doubt this was decided on purpose.
IMO it was more a side effect of the implementation, which had messy corners
(the fact that the tokenizer did produce two tokens $- and positive number)

I would add that this was undocumented, dialect specific, and a false good idea letting newbies think that they can use unary prefixed operators...

There is no such thing in the language.

Oh, and this even has changed in Squeak a few years ago:

-------------------------------------------------------

http://source.squeak.org/trunk/Compiler-nice.120.mcz

==================== Summary ====================

Name: Compiler-nice.120
Author: nice
Time: 23 February 2010, 5:14:44.049 pm
UUID: 9429cc05-281b-484e-94c2-bd0baf4f5230
Ancestors: Compiler-nice.119

Authorize - at any position in binary selectors (like VW 7.7)
See http://bugs.squeak.org/view.php?id=3616
Address the problem of compiling 1@-2 with following strategy:

If compiler is non interactive, then compile with backward compatibility 1 @ (-2).
If compiler is interactive, propose a menu to disambiguate and insert a proper space.
1@ -2 -> MessageSend receiver: 1 selector: #'@' argument: -2
1@- 2 -> MessageSend receiver: 1 selector: #'@-' argument: 2

Warning: Squeak did understand (1@-�� 2) as (1 @ (-2))....
I didn't do anything to support this vicious Squeakism, and by now the semantics are change.

2015-09-24 9:25 GMT+02:00 Cl��ment Bera <bera.clement@gmail.com>:

2015-09-24 8:19 GMT+02:00 Peter Uhn��k <i.uhnak@gmail.com>:
>�� - 250 * 1.5 returns -2.25

why is this valid syntax?

It should not. RBParser bug. This is not valid Smalltalk syntax. As Ben showed similar cases raise an error but this one generate incorrect compiledMethod instead.
��

On Thu, Sep 24, 2015 at 5:35 AM, Ben Coman <btc@openinworld.com> wrote:
RBParser parseExpression: '-250 * 1.5' => "RBMessageNode(-250 * 1.5)"
RBParser parseExpression: '- 250 * 1.5'�� =>�� "RBMessageNode(*1.5 * 1.5)"

RBParser parseExpression: '250 * -1.5'�� =>�� "RBMessageNode(250 * -1.5)"
RBParser parseExpression: '250 * - 1.5'�� =>�� MNU RBToken>>realvalue.

RBParser parseExpression: '-250'�� =>�� "RBLiteralValueNode(-250)"
RBParser parseExpression: '- 250' =>�� MNU RBToken>>realvalue.

So how significant should be the space between the negative sign and its number?

cheers -ben

On Thu, Sep 24, 2015 at 6:34 AM, Cl��ment Bera <bera.clement@gmail.com> wrote:
> RBParser parseExpression: '- 250 * 1.5'�� => Answers�� RBMessageNode(*1.5 *
> 1.5)
>
> Second expression looks correct.
>
> Hence RBParser bug.
>
> 2015-09-23 23:42 GMT+02:00 phil@highoctane.be <phil@highoctane.be>:
>>
>> debug it on the first one gives "MNU: receiver of "doSemanticAnalyisIn:"
>> is nil.
>>
>> Weird.
>>
>> On Wed, Sep 23, 2015 at 8:40 AM, stepharo <stepharo@free.fr> wrote:
>>>
>>> Hi guys
>>>
>>> I think that this is quite bad that
>>>�� - 250 * 1.5 returns -2.25
>>>
>>> while
>>>
>>>�� -250 * 1.5 return 375
>>>
>>> stef
>>>
>>
>