Oops.
MACRO: printf ( string -- quot: ( ..a string -- ..b ) )
MACRO: sprintf ( string -- quot: ( ..a string -- ..b string ) )
On Thu, Jan 18, 2018 at 3:02 PM John Benediktsson <mrj...@gmail.com> wrote:
> MACRO: always produces a quot.
>
> But when it's "called" it's whatever the stack effect of that produced
> quot is when it's expanded into the calling site.
>
>
>
>
> On Thu, Jan 18, 2018 at 12:36 PM, Alexander Ilin <ajs...@yandex.ru> wrote:
>
>> O-kay... Let me try to ask my question again...
>>
>> I've read the blog post that you linked to. In there I found the
>> following declaration:
>> `*MACRO:* printf ( format-string -- )`
>>
>> This means that the macro takes one argument and removes it from the
>> stack, doesn't put anything back.
>>
>> But in the actual source code of the `formatting` vocab the declaration
>> is: `MACRO: printf ( format-string -- quot )`, which looks as if the
>> `printf` word takes one parameter off the stack and puts one item back on
>> the stack.
>>
>> ... which is not true: it doesn't put a quotation on the stack, because
>> it calls the quotation.
>>
>> So, I have two questions, basically:
>>
>> 1) why not change the declaration in `formatting` to ``MACRO: printf (
>> format-string -- )` - with no output onto the stack?
>> 2) are `MACRO:`s allowed to have invalid stack effect declaration? Are
>> they somehow exempted from the compiler checks?
>>
>> I'm asking this because the declared stack effect shows up in the
>> documentation, and is confusing. Reading it gives the expression that it
>> should be used with an extra `call` to the produced quotation:
>> `11 "he%do, world" printf call`
>>
>> 18.01.2018, 19:00, "John Benediktsson" <mrj...@gmail.com>:
>>
>> Both of those are macros (basically special words that produce a
>> quotation), so when "called" they are first macro-expanded into a quotation
>> and then that quotation is called, with whatever stack effect it has.
>>
>> IN: scratchpad 1 2 3 "%s %s %s" printf
>> 1 2 3
>>
>> IN: scratchpad [ "%s %s %s" printf ] infer
>> ( x x x -- )
>>
>> IN: scratchpad [ "%s %s %s" printf ] expand-macros
>> [
>> [ present ] 2 ndip [ " " ] 2 ndip [ present ] 1 ndip
>> [ " " ] 1 ndip [ present ] 0 ndip output-stream get
>> [ stream-write ] curry 5 napply
>> ]
>>
>> Maybe the article I wrote when developing it would help:
>>
>> https://re-factor.blogspot.com/2011/08/printf.html
>>
>>
>> On Thu, Jan 18, 2018 at 4:32 AM, Alexander Ilin <ajs...@yandex.ru> wrote:
>>
>> Hello!
>>
>> There are two similar words: printf and sprintf. They have similar
>> stack effects, but different behavior.
>>
>> MACRO: sprintf ( format-string -- result )
>> leaves a string on stack
>>
>> MACRO: printf ( format-string -- quot )
>> leaves nothing on stack despite the stack effect specified
>>
>> How come `printf` does'n obey its declared stack effect?
>>
>> ---=====---
>> Александр
>>
>>
>>
>> ---=====---
>> Александр
>>
>>
>>
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>
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