Re: [fpc-pascal] Re: Very odd case parsing problem
leledumbo wrote:
I can fix that either by putting a semicolon before the else- which I
believe is strictly incorrect
Nope, that's correct. Take a look at the syntax diagram for case statement
here:
http://www.freepascal.org/docs-html/ref/refsu50.html
As you can see, each "case" is terminated by ";". From the parser point of
view, your code is exactly parsed as:
No, that shows a semicolon separating successive cases, not terminating
each one. What's more statement can be a compound statement and
that's similarly defined as using ; as a separator.
Bit of an old chestnut, and my recollection is that an extra semicolon
would crash some versions of Turbo Pascal. I'm not sure where my copy of
J&W is, so I can't go back to the BNF... but it wouldn't help since
else was added to the case statement by Turbo Pascal which explicitly has
case expression of case-element { ; case-element } else
where a case-element ends with a statement which can be a
compound-statement which again defines ; as a separator.
(Oh Lord this is all we need: a syntax war to round off the year.)
--
Mark Morgan Lloyd
markMLl .AT. telemetry.co .DOT. uk
[Opinions above are the author's, not those of his employers or colleagues]
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Re: [fpc-pascal] Re: Very odd case parsing problem
Am 29.12.2013 09:10 schrieb "Mark Morgan Lloyd" <
markmll.fpc-pas...@telemetry.co.uk>:
>
> leledumbo wrote:
>>>
>>> I can fix that either by putting a semicolon before the else- which I
>>
>> believe is strictly incorrect
>>
>> Nope, that's correct. Take a look at the syntax diagram for case
statement
>> here:
>> http://www.freepascal.org/docs-html/ref/refsu50.html
>>
>> As you can see, each "case" is terminated by ";". From the parser point
of
>> view, your code is exactly parsed as:
>
>
> No, that shows a semicolon separating successive cases, not terminating
each one. What's more statement can be a compound statement and that's
similarly defined as using ; as a separator.
>
> Bit of an old chestnut, and my recollection is that an extra semicolon
would crash some versions of Turbo Pascal. I'm not sure where my copy of
J&W is, so I can't go back to the BNF... but it wouldn't help since else
was added to the case statement by Turbo Pascal which explicitly has
>
> case expression of case-element { ; case-element } else
>
> where a case-element ends with a statement which can be a
compound-statement which again defines ; as a separator.
>
> (Oh Lord this is all we need: a syntax war to round off the year.)
In case you don't need Delphi compatibility you can use "otherwise" instead
of "else" inside a case-statement. This keyword comes from the ISO dialects
and is enabled in all modes.
Regards,
Sven
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Re: [fpc-pascal] Very odd case parsing problem
On 2013-12-28 15:47, Mark Morgan Lloyd wrote: I can fix that either by putting a semicolon before the else- which I believe is strictly incorrect- or by putting begin/end around that conditional, or by inserting a dummy statement before the else like quit_: if High(lexemeListArray) = 1 then begin end; nop: begin end else The problem is the compiler associates the else with the if..then and not with the case statement. All your fixes break the possible connection between the else and the if..then and that's why they work. Your first fix (to just add a semicolon) would be my preferred one. I have lots of code that is written that way. I'm not sure why you think this is "strictly incorrect". -- Cheers! Rich Saunders ___ fpc-pascal maillist - fpc-pascal@lists.freepascal.org http://lists.freepascal.org/mailman/listinfo/fpc-pascal
[fpc-pascal] Android cross-compiler: arm-linux-androideabi- binutilsprefix
Complete log: http://pastebin.com/Bj2EGmWD FPC trunk, trying to get an Android ARM cross compiler going. 1. Optimistically using FPC 2.6.2 as bootstrap - should I be using trunk? (Trying that now anyway) Copied Android NDK crossbinutils (as.exe etc) and libs (crtbegin_dynamic.o, libc.so) etc. This is the command I let fpcup execute to build the cross compiler: Executing : C:\development\fpcbootstrap\make.exe "FPC=C:\development\fpcbootstrap\ppc386.exe" "--directory=C:\development\fpctrunk" "INSTALL_PREFIX=C:\development\fpctrunk" "CROSSBINDIR=C:\development\cross\bin\arm-android" "UPXPROG=echo" "COPYTREE=echo" "all" "OS_TARGET=android" "CPU_TARGET=arm" "CROSSOPT= -CpARMV6" "OPT= -Xd -FlC:\development\cross\lib\arm-android" 2. Running the module I get quite far until I suddenly see reference to a binutils prefix that I haven't set...: make.exe[5]: Entering directory `C:/development/fpctrunk/rtl/android' ... system.pp(380) Error: Assembler arm-linux-androideabi-as.exe not found, switching to external assembling Am I doing something wrong? Should I rename the binutils from the NDK and use -XP/BINUTILSPREFIX? This entry in fpc.cfg (fpc trunk) is ominous: # for android cross-prefix is set by compiler #ifdef android #undef NEEDCROSSBINUTILS #endif Does fpc (trunk) require arm-linux-androideabi- ? (And if so, why?) ___ fpc-pascal maillist - fpc-pascal@lists.freepascal.org http://lists.freepascal.org/mailman/listinfo/fpc-pascal
Re: [fpc-pascal] Android cross-compiler: arm-linux-androideabi- binutilsprefix
Am 29.12.2013 14:12, schrieb Reinier Olislagers:
> Complete log: http://pastebin.com/Bj2EGmWD
>
> FPC trunk, trying to get an Android ARM cross compiler going.
> 1. Optimistically using FPC 2.6.2 as bootstrap - should I be using
> trunk? (Trying that now anyway)
>
> Copied Android NDK crossbinutils (as.exe etc) and libs
> (crtbegin_dynamic.o, libc.so) etc.
>
> This is the command I let fpcup execute to build the cross compiler:
> Executing : C:\development\fpcbootstrap\make.exe
> "FPC=C:\development\fpcbootstrap\ppc386.exe"
> "--directory=C:\development\fpctrunk"
> "INSTALL_PREFIX=C:\development\fpctrunk"
> "CROSSBINDIR=C:\development\cross\bin\arm-android" "UPXPROG=echo"
> "COPYTREE=echo" "all" "OS_TARGET=android" "CPU_TARGET=arm" "CROSSOPT=
> -CpARMV6" "OPT= -Xd -FlC:\development\cross\lib\arm-android"
>
> 2. Running the module I get quite far until I suddenly see reference to
> a binutils prefix that I haven't set...:
> make.exe[5]: Entering directory `C:/development/fpctrunk/rtl/android'
> ...
> system.pp(380) Error: Assembler arm-linux-androideabi-as.exe not found,
> switching to external assembling
>
> Am I doing something wrong? Should I rename the binutils from the NDK
> and use -XP/BINUTILSPREFIX?
>
> This entry in fpc.cfg (fpc trunk) is ominous:
> # for android cross-prefix is set by compiler
> #ifdef android
> #undef NEEDCROSSBINUTILS
> #endif
>
> Does fpc (trunk) require arm-linux-androideabi- ?
> (And if so, why?)
>From fpc/compiler/options.pas:
{ Set up a default prefix for binutils when cross-compiling }
if source_info.system<>target_info.system then
case target_info.system of
{ Use standard Android NDK prefixes }
system_arm_android:
utilsprefix:='arm-linux-androideabi-';
system_i386_android:
utilsprefix:='i686-linux-android-';
end;
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[fpc-pascal] Re: Very odd case parsing problem
> No, that shows a semicolon separating successive cases, not terminating each one Right, sorry I misinterpret "separate" with "terminate". -- View this message in context: http://free-pascal-general.1045716.n5.nabble.com/Very-odd-case-parsing-problem-tp5717723p5717731.html Sent from the Free Pascal - General mailing list archive at Nabble.com. ___ fpc-pascal maillist - fpc-pascal@lists.freepascal.org http://lists.freepascal.org/mailman/listinfo/fpc-pascal
Re: [fpc-pascal] Android cross-compiler: arm-linux-androideabi- binutilsprefix
On 29/12/2013 14:22, Florian Klämpfl wrote:
> Am 29.12.2013 14:12, schrieb Reinier Olislagers:
>> Does fpc (trunk) require arm-linux-androideabi- ?
>> (And if so, why?)
>
>>From fpc/compiler/options.pas:
>
> { Set up a default prefix for binutils when cross-compiling }
> if source_info.system<>target_info.system then
> case target_info.system of
> { Use standard Android NDK prefixes }
> system_arm_android:
> utilsprefix:='arm-linux-androideabi-';
> system_i386_android:
> utilsprefix:='i686-linux-android-';
> end;
Thanks.
I see I probably copied over the wrong directory from the NDK: the one
from arm-linux has
android-ndk-r9c\toolchains\arm-linux-androideabi-4.8\prebuilt\windows-x86_64\arm-linux-androideabi\bin\as.exe
etc
as well as
D:\cop\t\android-ndk-r9c\toolchains\arm-linux-androideabi-4.8\prebuilt\windows-x86_64\bin\arm-linux-androideabi-as.exe
Sorry about that; I'll fix things up, try again... and get back if needed.
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Re: [fpc-pascal] Very odd case parsing problem
On 29/12/2013 07:33, Mark Morgan Lloyd wrote:
Saunders, Rich wrote:
On 2013-12-28 15:47, Mark Morgan Lloyd wrote:
quit_: if High(lexemeListArray) = 1 then begin
end;
nop: begin end
else
Drat- a dangling else in a case! I should have spotted that, but
instead spent an hour or so picking at it.
1) If you use Lazarus then you can have case-labels highlighted (e.g add
underline/border, blend foreground by mixing in another color, bold,
...) It is in the color config.
That will (in this case) not highlight the else, so you will know the
else is part of the if.
2) I tried your code and it compiles (2.6.2 win32)
{$mode objfpc}{$H+}
procedure TForm1.FormCreate(Sender: TObject);
var
a: (help, help_, quit_);
b: Integer;
begin
try
case a of
help:begin
end;
help_: begin
end;
quit_: if b = 1 then begin
end
else
end // line 323
finally
end;
end;
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Re: [fpc-pascal] Very odd case parsing problem
Martin Frb wrote:
Drat- a dangling else in a case! I should have spotted that, but
instead spent an hour or so picking at it.
1) If you use Lazarus then you can have case-labels highlighted (e.g add
underline/border, blend foreground by mixing in another color, bold,
...) It is in the color config.
That will (in this case) not highlight the else, so you will know the
else is part of the if.
Thanks, noted.
2) I tried your code and it compiles (2.6.2 win32)
{$mode objfpc}{$H+}
procedure TForm1.FormCreate(Sender: TObject);
var
a: (help, help_, quit_);
b: Integer;
begin
try
case a of
help:begin
end;
help_: begin
end;
quit_: if b = 1 then begin
end
else
end // line 323
finally
end;
end;
There were additional statements in between the else and the final
end. Since the else associated with a case accepts multiple
statements while the else associated with an if doesn't, the
compiler was getting confused by what it thought was a spurious end
statement. I'm sure I've been bitten by this one before, and recently
enough for it to be embarrassing.
I find myself habitually putting in an explicit else part in each
case statement, even if it's empty. That's a habit from Modula-2 days,
I can't remember what the spec said but some (if not all) compilers
insisted on it. In view of the potential for a dangling else, I'm not
sure whether that's a good or a bad habit.
--
Mark Morgan Lloyd
markMLl .AT. telemetry.co .DOT. uk
[Opinions above are the author's, not those of his employers or colleagues]
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Re: [fpc-pascal] Very odd case parsing problem
On 29.12.2013 15:06, Martin Frb wrote: On 29/12/2013 07:33, Mark Morgan Lloyd wrote: Saunders, Rich wrote: On 2013-12-28 15:47, Mark Morgan Lloyd wrote: quit_: if High(lexemeListArray) = 1 then begin end; nop: begin end else Drat- a dangling else in a case! I should have spotted that, but instead spent an hour or so picking at it. 1) If you use Lazarus then you can have case-labels highlighted (e.g add underline/border, blend foreground by mixing in another color, bold, ...) It is in the color config. That will (in this case) not highlight the else, so you will know the else is part of the if. Does Lazarus recognize "otherwise" as an alternative for "else" inside a "case"-statement as well? Regards, Sven ___ fpc-pascal maillist - fpc-pascal@lists.freepascal.org http://lists.freepascal.org/mailman/listinfo/fpc-pascal
Re: [fpc-pascal] Very odd case parsing problem
On 29/12/2013 16:37, Sven Barth wrote: Does Lazarus recognize "otherwise" as an alternative for "else" inside a "case"-statement as well? Not yet ___ fpc-pascal maillist - fpc-pascal@lists.freepascal.org http://lists.freepascal.org/mailman/listinfo/fpc-pascal
Re: [fpc-pascal] Very odd case parsing problem
On 29/12/2013 17:08, Martin Frb wrote: On 29/12/2013 16:37, Sven Barth wrote: Does Lazarus recognize "otherwise" as an alternative for "else" inside a "case"-statement as well? Not yet Now 1.3 does ___ fpc-pascal maillist - fpc-pascal@lists.freepascal.org http://lists.freepascal.org/mailman/listinfo/fpc-pascal
Re: [fpc-pascal] Very odd case parsing problem
On 29.12.2013 18:20, Martin Frb wrote: On 29/12/2013 17:08, Martin Frb wrote: On 29/12/2013 16:37, Sven Barth wrote: Does Lazarus recognize "otherwise" as an alternative for "else" inside a "case"-statement as well? Not yet Now 1.3 does Great! :) Regards, Sven ___ fpc-pascal maillist - fpc-pascal@lists.freepascal.org http://lists.freepascal.org/mailman/listinfo/fpc-pascal
Re: [fpc-pascal] Very odd case parsing problem
Sven Barth wrote: On 29.12.2013 18:20, Martin Frb wrote: On 29/12/2013 17:08, Martin Frb wrote: On 29/12/2013 16:37, Sven Barth wrote: Does Lazarus recognize "otherwise" as an alternative for "else" inside a "case"-statement as well? Not yet Now 1.3 does Great! :) Ruefully agrees :-) -- Mark Morgan Lloyd markMLl .AT. telemetry.co .DOT. uk [Opinions above are the author's, not those of his employers or colleagues] ___ fpc-pascal maillist - fpc-pascal@lists.freepascal.org http://lists.freepascal.org/mailman/listinfo/fpc-pascal
