Re: [Nasm-devel] [nasm:master] BR30730640: Restore preprocessor token concatenation rules

[anonymous c. <nas...@us...>]

>> >> > expand_smacro
>> >> >    [(TOK_ID|TOK_PREPROC_ID)][(TOK_ID|TOK_PREPROC_ID|TOK_NUMBER)]
>> >> >
>> >> > expand_mmac_params
>> >> >    [(TOK_ID|TOK_NUMBER|TOK_FLOAT)][(TOK_ID|TOK_NUMBER|TOK_FLOAT|TOK_OTHER)]
>> >>
>> >> The above permit concatenations that result in invalid
>> >> tokens, and therefore need to be tightened. Try these
>> >> rules instead:
>> >>
>> >> - whitespace(s)/tab(s) with whitespace(s)/tab(s)
>> >> - identifiers with either identifiers or numbers or $/$$
>> >> - preprocessor identifiers or numbers with numbers
>> >> - $ with identifiers or numbers that don't begin with $
>> >>
>> >> I don't know enough about TOK_FLOAT to comment.
>> >
>> > OK, thanks for comments, I'll take a look tomorrow. But basically I would
>> > rather like to hear which exactly invalid tokens you mean? Mind
>> > to elaborate if you have some spare minutes? Also I fear this part of
>>
>> In your first set of rules you cannot have TOK_PREPROC_ID on
>> the right side, since it may start with a character that cannot be
>> inside a TOK_ID or TOK_NUMBER.
>
> We still have to support it since people use it
>
> %assign %$_uses 0
> %rep 4
>        %assign %$_ur%$_uses %$_uses
>        mov eax, %$_ur%$_uses
>        %assign %$_uses %$_uses+1
> %endrep
>
> and friends, we just can't drop it.

Even if I wrap your sample code in %PUSH and %POP
it does not seem to work:

# ./nasm 0.asm
0.asm:8: error: `%assign' expects a macro identifier
0.asm:8: error: `%assign' expects a macro identifier
0.asm:8: error: `%assign' expects a macro identifier

>> In your second set of rules you cannot have TOK_NUMBER plus
>> TOK_ID, let alone xxx plus any TOK_OTHER, for the same basic
>> reason as above.
>
> Well, as far as I see there can't be a combination of TOK_NUM+TOK_ID
> as a single term to be concat'ed, it's written this way in mask
> due to simplicity of handling.
>
> So at moment I fail to see what exactly may produce wrong concat'ed
> terms. Please, if you have a real example with code -- poke me, thanks.

# cat 0.asm
; a number and an identifier

%define TOK_NUM 1
%define TOK_ID @

; prove it

%ifnum TOK_NUM
 db TOK_NUM
%endif

%ifid TOK_ID
 TOK_ID: jmp TOK_ID
%endif

; implicit and explicit concatenation

%define concat_explicit(X,Y) X%+Y

%macro concat_implicit 2
 %define Xi %1%2
%endm

; exercise both concatenations

%define Xe concat_explicit(TOK_NUM,TOK_ID)

concat_implicit TOK_NUM,TOK_ID

; do we have numbers?

%ifnum Xe
 nop ; yes we do, due to bad concatenation
%endif

%ifnum Xi
 nop ; yes we do, due to bad concatenation
%endif

; really?

%ifdef TRY_Xe
 db Xe ; no, because 1# is not a number
%endif

%ifdef TRY_Xi
 db Xi ; no, because 1# is not a number
%endif

; EOF

# ./nasm 0.asm -l 0.lst -DTRY_Xe
0.asm:43: error: comma expected after operand 1

# ./nasm 0.asm -l 0.lst -DTRY_Xi
0.asm:47: error: comma expected after operand 1

# ./nasm 0.asm -l 0.lst

# cat 0.lst
     1                                  ; a number and an identifier
     2
     3                                  %define TOK_NUM 1
     4                                  %define TOK_ID @
     5
     6                                  ; prove it
     7
     8                                  %ifnum TOK_NUM
     9 00000000 01                       db TOK_NUM
    10                                  %endif
    11
    12                                  %ifid TOK_ID
    13 00000001 EBFE                     TOK_ID: jmp TOK_ID
    14                                  %endif
    15
    16                                  ; implicit and explicit concatenation
    17
    18                                  %define concat_explicit(X,Y) X%+Y
    19
    20                                  %macro concat_implicit 2
    21                                   %define Xi %1%2
    22                                  %endm
    23
    24                                  ; exercise both concatenations
    25
    26                                  %define Xe
concat_explicit(TOK_NUM,TOK_ID)
    27
    28                                  concat_implicit TOK_NUM,TOK_ID
    29                              <1>  %define Xi %1%2
    30
    31                                  ; do we have numbers?
    32
    33                                  %ifnum Xe
    34 00000003 90                       nop ; yes we do, due to bad
concatenation
    35                                  %endif
    36
    37                                  %ifnum Xi
    38 00000004 90                       nop ; yes we do, due to bad
concatenation
    39                                  %endif
    40
    41                                  ; really?
    42
    43                                  %ifdef TRY_Xe
    44                                   db Xe ; no, because 1# is not a number
    45                                  %endif
    46
    47                                  %ifdef TRY_Xi
    48                                   db Xi ; no, because 1# is not a number
    49                                  %endif
    50
    51                                  ; EOF