Hello All,

I've just digged into
NCITS J20 DRAFT December, 1997 33 of ANSI Smalltalk Standard revision
1.9; in short:
- 'White space is allowed between the '-' and the <number>' for a
numeric literal; and
- 'If a negative <number literal> follows a binary selector there must
intervening white space.'

So your example

>>> On 13.05.2006 02:10, nicolas cellier wrote: nc>... nc> Funny, in
>>> current 3.9 spaces are ignored: nc> i have '1 +-   2' interpreted
>>> as (1) + (-2)
>>>...

is totally legal, but
  x+-1
should not be parsed as
  (x) + (-1)
. I'm interpreting the standard in this case - at least I think it can
be interpreted this way (see below for the definition of binary
operators) - as to parse it as
  (x) +- (1)
, +- being a binary selector.

We should follow the standard IMO, this means to allow
  x+-1
(here I have changed my mind after looking into it). In spite of this I
think it is not a good style to omit spaces here (and it gives a MNU
later, if +- is not defined)...

For points like
  0 at -1
this could give the workaround of defining
  @-
as operator (and @+ , too) much sense, because after the standard 0 at -1
could be parsed as
  (0) @- (1)
. Moreover a compile warning - 'Please insert spaces! This will be
parsed as ...; is this your intention?' or so - would make sense then
(since the extra message send here decreases performance).

Snippets from the standard draft:

> 3.4.6.1 Numeric Literals 
> 
>       Numbers are objects that represent numerical values. Numeric literals are used to create numeric 
>       objects which have specific values and numeric representations. 
> 
>        
>            <number literal> ::= ['-'] <number> 
>            <number> ::= integer | float | scaledDecimal 
> 
>       If the preceding '-' is not present the value of the numeric object is a positive number. If the '-' is 
>       present the value of the numeric object is the negative number that is the negation of the positive 
>       number defined by the <number> clause. White space is allowed between the '-' and the 
>       <number>. 
>...

> 3.5.5 Operators 
> 
>       Three types of operator tokens are defined in Smalltalk: binary selectors, the return operator, and 
>       the assignment operator. 
> 
>       . 
>             binaryCharacter ::= 
>                       '!' | '%' | '&'' | '*' | '+' | ','' | '/' | '<' | '=' | '>' | '?' | '@' | '\' | '~' | '|' | '-' 
>             binarySelector ::= binaryCharacter+ 
>              
>             returnOperator ::= '^' 
>              
>             assignmentOperator ::=  ':=' 
> 
>       Binary selectors are method selectors that appear similar to mathematical operators. A binary 
>       selector may be any length greater than or equal to one. If a negative <number literal> follows a 
>       binary selector there must intervening white space. 
> 
>       An implementation may define additional binaryCharacters but their use may result in a non-
>       portable program. 


Regards,
Stephan

PS: Nice that you already have code for finding critical cases.

On 15.05.2006 22:27, nicolas cellier wrote:
>...
-- 
Stephan Rudlof (sr at evolgo.de)
   "Genius doesn't work on an assembly line basis.
    You can't simply say, 'Today I will be brilliant.'"
    -- Kirk, "The Ultimate Computer", stardate 4731.3