Hi, Am 2011-04-16 um 13:32 schrieb Ted F.A. van Gaalen:

Hi there.

I am probably not the first, and will not be the last person to come up with this suggestion, neverTheLess:

To increment a numeric value I would like to write:

aNum := 1. aNum ++. to increment it aNum --. to decrement it

instead of: aNum := aNum + 1.

For reasons of efficiency and readability.

Why? Most, if not all, of today's computer processors ( they used to be called microprocessors :o) have INCrement en DECrement instructions, which are much more efficient than addition and subtraction instructions. (less clock cycles, perhaps even just one)

Interestingly, this is already done when using a JIT, eg, the CogVM. But what is more important is, that in Smalltalk, Integers are unmodifiable. There are different concepts: in C, i++ means, "increase the number in the memory cell that i represents" however, in Smalltalk, i ++ would mean "send the object that is stored in i the message #++" And if a number, eg 42, is stored in i, then this would mean "send 42 the message #++" but what should the result be? should 42 transform itself into 43? Moreover, it is bad style in Object-Oriented programming to rely on side effects of a message: You're implicitly saying "I want the state of the object in i to change and rely on it later-on" whereas i := i + 1 is explicitly saying "I want a number greater than i and work with it later-on"

Of course, the work should to be done by primitives, which directly utilizes the processor's INC, DEC instructions.

As I said this is subject to a JIT.

So, wouldn't it be convenient to implement these ++ and --- methods in Pharo? and VM. I am not sure, but I suspect also a number of system classes e.g. in do: [:i|...] would perform better, wenn this method/ instruction is supported?

I don't think so. So Long, -Tobias

On 16 April 2011 13:32, Ted F.A. van Gaalen <tedvga@gmail.com> wrote:

Hi there.

I am probably not the first, and will not be the last person to come up with this suggestion, neverTheLess:

To increment a numeric value I would like to write:

aNum := 1. aNum ++.             to increment it aNum --.             to decrement it

this is wrong smalltalk syntax. ++ and -- are binary messages, which means you should pass an argument to message, i.e: num ++ x num -- y. If you want unary messages, use word: num increment num decrement unless of course you want to extend the number of special operators, which are only: ':=' for assignment and '^' for return. So, you wanna increase the number of syntax rules to either introduce new operators (++/--) or add reserved words (increment/decrement). But if we follow that road, then next day one would argue why we don't have operators like +=, *=, -= and so on.. And then smalltalk will slowly turn into C dialect, where all language semantics available through syntax, instead through implementation & message sends. Smalltalk having very small number of syntax rules comparing to other high level languages. And this is one of its best characteristics , among the rest. So i prefer it to be staying this way.

instead of: aNum := aNum + 1.

For reasons of efficiency and readability.

Why? Most, if not all, of today's computer processors ( they used to be called microprocessors :o) have INCrement en DECrement instructions, which are much more efficient than addition and subtraction instructions. (less clock cycles, perhaps even just one)

Of course, the work should to be done by primitives, which directly utilizes the processor's INC, DEC instructions.

So, wouldn't it be convenient to implement these ++ and --- methods in Pharo? and VM.  I am not sure, but I suspect also a number of system classes e.g. in     do: [:i|...]   would perform better, wenn this method/ instruction is supported?

?

Kind Regards Ted Currently making/learning Pharo/Seaside app.

-- Best regards, Igor Stasenko AKA sig.