Re: [patch, fortran] PR109662 Namelist input with comma after name accepted

[Harald Anlauf <anlauf@gmx.de>]

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Hi Jerry,

I've made a small compiler survey how they behave on namelist read
from an internal unit when:

1.) there is a single input line of the type
"&stuff" // testchar // " n = 666/"

2.) the input spans 2 lines split after the testchar

3.) same as 2.) but first line right-adjusted

See attached source code.

Competitors: Intel, NAG, NVidia, gfortran at r14-547 with -std=f2018.

My findings were (last column is iostat, next-to-last is n read or -1):

NAG:

  Compiler version = NAG Fortran Compiler Release 7.1(Hanzomon) Build 7101
  1-line:       > < 666 0
  2-line/left:  > < 666 0
  2-line/right: > < 666 0
  1-line:       >!< -1 187
  2-line/left:  >!< -1 187
  2-line/right: >!< -1 187
  1-line:       >/< -1 187
  2-line/left:  >/< -1 187
  2-line/right: >/< -1 187
  1-line:       >,< -1 187
  2-line/left:  >,< -1 187
  2-line/right: >,< -1 187
  1-line:       >;< -1 187
  2-line/left:  >;< -1 187
  2-line/right: >;< -1 187
  1-line:       tab 666 0
  2-line/left:  tab 666 0
  2-line/right: tab 666 0
  1-line:       lf -1 187
  2-line/left:  lf -1 187
  2-line/right: lf -1 187
  1-line:       ret -1 187
  2-line/left:  ret -1 187
  2-line/right: ret -1 187

My interpretation of this is that NAG treats tab as (white)space,
everything else gives an error.  This is the strictest compiler.

Intel:

  Compiler version = Intel(R) Fortran Intel(R) 64 Compiler Classic for
applications running on Intel(R) 64, Version 2021.9.0 Build 20230302_000000
  1-line:       > <         666           0
  2-line/left:  > <         666           0
  2-line/right: > <         666           0
  1-line:       >!<          -1          -1
  2-line/left:  >!<         666           0
  2-line/right: >!<         666           0
  1-line:       >/<          -1           0
  2-line/left:  >/<          -1           0
  2-line/right: >/<          -1           0
  1-line:       >,<          -1          17
  2-line/left:  >,<          -1          17
  2-line/right: >,<          -1          17
  1-line:       >;<          -1          17
  2-line/left:  >;<          -1          17
  2-line/right: >;<          -1          17
  1-line:       tab         666           0
  2-line/left:  tab         666           0
  2-line/right: tab         666           0
  1-line:       lf         666           0
  2-line/left:  lf         666           0
  2-line/right: lf         666           0
  1-line:       ret          -1          17
  2-line/left:  ret          -1          17
  2-line/right: ret          -1          17

Nvidia:

  Compiler version = nvfortran 23.3-0
  1-line:       > <          666            0
  2-line/left:  > <          666            0
  2-line/right: > <          666            0
  1-line:       >!<           -1           -1
  2-line/left:  >!<           -1           -1
  2-line/right: >!<           -1           -1
  1-line:       >/<           -1           -1
  2-line/left:  >/<           -1           -1
  2-line/right: >/<           -1           -1
  1-line:       >,<           -1           -1
  2-line/left:  >,<           -1           -1
  2-line/right: >,<           -1           -1
  1-line:       >;<           -1           -1
  2-line/left:  >;<           -1           -1
  2-line/right: >;<           -1           -1
  1-line:       tab          666            0
  2-line/left:  tab          666            0
  2-line/right: tab          666            0
  1-line:       lf           -1           -1
  2-line/left:  lf          666            0
  2-line/right: lf          666            0
  1-line:       ret          666            0
  2-line/left:  ret          666            0
  2-line/right: ret          666            0

gfortran (see above):

  Compiler version = GCC version 14.0.0 20230506 (experimental)
  1-line:       > <         666           0
  2-line/left:  > <         666           0
  2-line/right: > <         666           0
  1-line:       >!<          -1          -1
  2-line/left:  >!<          -1           0
  2-line/right: >!<         666           0
  1-line:       >/<          -1           0
  2-line/left:  >/<          -1           0
  2-line/right: >/<          -1           0
  1-line:       >,<         666        5010
  2-line/left:  >,<         666        5010
  2-line/right: >,<         666        5010
  1-line:       >;<         666           0
  2-line/left:  >;<         666           0
  2-line/right: >;<         666           0
  1-line:       tab         666           0
  2-line/left:  tab         666           0
  2-line/right: tab         666           0
  1-line:       lf         666           0
  2-line/left:  lf         666           0
  2-line/right: lf         666           0
  1-line:       ret         666           0
  2-line/left:  ret         666           0
  2-line/right: ret         666           0


So there seems to be a consensus that "," and ";" must be rejected,
and tab is accepted (makes real sense), but already the termination
character "/" and comment character "!" are treated differently.
And how do we want to treat lf and ret in internal files with
-std=f20xx?

Cheers,
Harald


On 5/7/23 19:33, Jerry D via Gcc-patches wrote:
> On 5/6/23 11:15 AM, Harald Anlauf via Fortran wrote:
>> Hi Jerry, Steve,
>>
>> I think I have to pour a little water into the wine.
>>
>> The patch fixes the reported issue only for a comma after
>> the namelist name, but we still accept a few other illegal
>> characters, e.g. ';', because:
>>
>> #define is_separator(c) (c == '/' ||  c == ',' || c == '\n' || c == ' ' \
>>                           || c == '\t' || c == '\r' || c == ';' || \
>>               (dtp->u.p.namelist_mode && c == '!'))
>>
>> We don't want that in standard conformance mode, or do we?
>>
>> Cheers,
>> Harald
>>
>> On 5/6/23 06:02, Steve Kargl via Gcc-patches wrote:
>>> On Fri, May 05, 2023 at 08:41:48PM -0700, Jerry D via Fortran wrote:
>>>> The attached patch adds a check for the invalid comma and emits a
>>>> runtime
>>>> error if -std=f95,f2003,f2018 are specified at compile time.
>>>>
>>>> Attached patch includes a new test case.
>>>>
>>>> Regression tested on x86_64-linux-gnu.
>>>>
>>>> OK for mainline?
>>>>
>>>
>>> Yes.  Thanks for the fix.  It's been a long time since
>>> I looked at libgfortran code and couldn't quite determine
>>> where to start to fix this.
>>>
>>
>
> As I think back, I don't recall ever seeing a semi-colon used after a
> NAMELIST name, so I think we should reject it always.  The other "soft"
> blanks we should allow.
>
> I will make a another patch on trunk to reject the semi-colon and if no
> one objects here I will test and push it.
>
> Regards,
>
> Jerry
>
>

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program testnmlread
  use iso_fortran_env, only: compiler_version
  implicit none
  print *,'Compiler version = ',trim(compiler_version())
  call test (" ")
  call test ("!")
  call test ("/")
  call test (",")
  call test (";")
  call test (achar(9),  "tab")
  call test (achar(10), "lf")
  call test (achar(13), "ret")
contains
  subroutine test (c, desc)
    character,    intent(in)           :: c
    character(*), intent(in), optional :: desc
    character(8)  :: d
    character(16) :: line, lines(2)
    integer       :: ios
    integer       :: n
    namelist/stuff/n
    character(*), parameter :: s1 = "&stuff", s2 = " n = 666/"

    d =  ">" // c // "<"; if (present (desc)) d = desc
    ! Prepare input:
    line     = s1 // c // s2
    lines(1) = s1 // c              ! Left-adjusted
    lines(2) = s2
    ! Single line input
    n = -1
    read(line,nml=stuff,iostat=ios)
    write(*,*) "1-line:       ", trim (d), n, ios
    ! Multi-line input
    n = -1
    read(lines,nml=stuff, iostat=ios)
    write(*,*) "2-line/left:  ", trim (d), n, ios
    lines(1) = adjustr (lines(1))   ! Right-adjust first line
    n = -1
    read(lines,nml=stuff, iostat=ios)
    write(*,*) "2-line/right: ", trim (d), n, ios
  end subroutine test
end program testnmlread