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Grammar bug <alnum> vs <alpha> #6688

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p6rt opened this issue Sep 25, 2018 · 13 comments
Open

Grammar bug <alnum> vs <alpha> #6688

p6rt opened this issue Sep 25, 2018 · 13 comments
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@p6rt
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@p6rt p6rt commented Sep 25, 2018

Migrated from rt.perl.org#133541 (status was 'open')

Searchable as RT133541$

@p6rt
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@p6rt p6rt commented Sep 25, 2018

From jvs@dyumnin.com

In the attached code, the only difference between the Grammars G0 and G1
is the defination of token 'type' it is defined as <alpha> in one case
and as <alnum> in another.

Since the string being matched is 'sc_in' both the alpha and alnum
tokens should have captured it. But we see the following result on
execution

=========== <alnum> Example==============
Nil
=========== <alpha> Example==============
「sc_in<foo> bar」
ruport => 「sc_in」
type => 「sc_in」
alpha => 「s」
alpha => 「c」
alpha => 「_」
alpha => 「i」
alpha => 「n」

Perl Version is

This is Rakudo Star version 2018.06 built on MoarVM version 2018.06
implementing Perl 6.c.

--
Vijayvithal
Dyumnin Semiconductors

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@p6rt
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@p6rt p6rt commented Sep 25, 2018

From jvs@dyumnin.com

grammar G0 {
  token TOP {<rport>|<ruport>.*}
  regex rport { <type>}
  rule ruport { <type>}
  #token type {<alpha>+}
  token type {<alnum>+}
}

grammar G1 {
  token TOP {<rport>|<ruport>.*}
  regex rport { <type>}
  rule ruport { <type>}
  token type {<alpha>+}
  #token type {<alnum>+}
}
my $str="sc_in<foo> bar";
say "=========== <alnum> Example==============";
say G0.parse($str);
say "=========== <alpha> Example==============";
say G1.parse($str);

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@p6rt
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@p6rt p6rt commented Sep 28, 2018

From @geekosaur

"_" is not an alphabetic character. It's allowed in "alnum" because that is
by intent what is \w in other regex implementations, which includes "_".

On Thu, Sep 27, 2018 at 10​:47 PM Vijayvithal <perl6-bugs-followup@​perl.org>
wrote​:

# New Ticket Created by Vijayvithal
# Please include the string​: [perl #​133541]
# in the subject line of all future correspondence about this issue.
# <URL​: https://rt-archive.perl.org/perl6/Ticket/Display.html?id=133541 >

In the attached code, the only difference between the Grammars G0 and G1
is the defination of token 'type' it is defined as <alpha> in one case
and as <alnum> in another.

Since the string being matched is 'sc_in' both the alpha and alnum
tokens should have captured it. But we see the following result on
execution

=========== <alnum> Example==============
Nil
=========== <alpha> Example==============
「sc_in<foo> bar」
ruport => 「sc_in」
type => 「sc_in」
alpha => 「s」
alpha => 「c」
alpha => 「_」
alpha => 「i」
alpha => 「n」

Perl Version is

This is Rakudo Star version 2018.06 built on MoarVM version 2018.06
implementing Perl 6.c.

--
Vijayvithal
Dyumnin Semiconductors

--
brandon s allbery kf8nh
allbery.b@​gmail.com

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@p6rt
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@p6rt p6rt commented Sep 28, 2018

The RT System itself - Status changed from 'new' to 'open'

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@p6rt
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@p6rt p6rt commented Sep 28, 2018

From @labster

Are you sure about that? Underscore has been part of the specs (synopses)
for <alpha> for at least 10 years, probably longer.

"_" ~~ /<alpha>/
「_」
alpha => 「_」

On Thu, Sep 27, 2018 at 7​:52 PM Brandon Allbery <allbery.b@​gmail.com> wrote​:

"_" is not an alphabetic character. It's allowed in "alnum" because that
is by intent what is \w in other regex implementations, which includes "_".

On Thu, Sep 27, 2018 at 10​:47 PM Vijayvithal <perl6-bugs-followup@​perl.org>
wrote​:

# New Ticket Created by Vijayvithal
# Please include the string​: [perl #​133541]
# in the subject line of all future correspondence about this issue.
# <URL​: https://rt-archive.perl.org/perl6/Ticket/Display.html?id=133541 >

In the attached code, the only difference between the Grammars G0 and G1
is the defination of token 'type' it is defined as <alpha> in one case
and as <alnum> in another.

Since the string being matched is 'sc_in' both the alpha and alnum
tokens should have captured it. But we see the following result on
execution

=========== <alnum> Example==============
Nil
=========== <alpha> Example==============
「sc_in<foo> bar」
ruport => 「sc_in」
type => 「sc_in」
alpha => 「s」
alpha => 「c」
alpha => 「_」
alpha => 「i」
alpha => 「n」

Perl Version is

This is Rakudo Star version 2018.06 built on MoarVM version 2018.06
implementing Perl 6.c.

--
Vijayvithal
Dyumnin Semiconductors

--
brandon s allbery kf8nh
allbery.b@​gmail.com

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@p6rt
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@p6rt p6rt commented Sep 28, 2018

From @pmichaud

The issue doesn't seem to be the underscore, because I get the same result even when converting the underscore into a letter ('b')​:

$ cat gentb.p6
grammar G0 {
  token TOP {<rport>|<ruport>.*}
  regex rport { <type>}
  rule ruport { <type>}
  #token type {<alpha>+}
  token type {<alnum>+}
}

grammar G1 {
  token TOP {<rport>|<ruport>.*}
  regex rport { <type>}
  rule ruport { <type>}
  token type {<alpha>+}
  #token type {<alnum>+}
}
my $str="scbin<foo> bar";
say "=========== <alnum> Example==============";
say G0.parse($str);
say "=========== <alpha> Example==============";
say G1.parse($str);

$ perl6 gentb.p6
=========== <alnum> Example==============
Nil
=========== <alpha> Example==============
「scbin<foo> bar」
ruport => 「scbin」
  type => 「scbin」
  alpha => 「s」
  alpha => 「c」
  alpha => 「b」
  alpha => 「i」
  alpha => 「n」
$

On Fri, Sep 28, 2018 at 02​:26​:41AM -0700, Brent Laabs wrote​:

Are you sure about that? Underscore has been part of the specs (synopses)
for <alpha> for at least 10 years, probably longer.

"_" ~~ /<alpha>/
「_」
alpha => 「_」

On Thu, Sep 27, 2018 at 7​:52 PM Brandon Allbery <allbery.b@​gmail.com> wrote​:

"_" is not an alphabetic character. It's allowed in "alnum" because that
is by intent what is \w in other regex implementations, which includes "_".

On Thu, Sep 27, 2018 at 10​:47 PM Vijayvithal <perl6-bugs-followup@​perl.org>
wrote​:

# New Ticket Created by Vijayvithal
# Please include the string​: [perl #​133541]
# in the subject line of all future correspondence about this issue.
# <URL​: https://rt-archive.perl.org/perl6/Ticket/Display.html?id=133541 >

In the attached code, the only difference between the Grammars G0 and G1
is the defination of token 'type' it is defined as <alpha> in one case
and as <alnum> in another.

Since the string being matched is 'sc_in' both the alpha and alnum
tokens should have captured it. But we see the following result on
execution

=========== <alnum> Example==============
Nil
=========== <alpha> Example==============
「sc_in<foo> bar」
ruport => 「sc_in」
type => 「sc_in」
alpha => 「s」
alpha => 「c」
alpha => 「_」
alpha => 「i」
alpha => 「n」

Perl Version is

This is Rakudo Star version 2018.06 built on MoarVM version 2018.06
implementing Perl 6.c.

--
Vijayvithal
Dyumnin Semiconductors

--
brandon s allbery kf8nh
allbery.b@​gmail.com

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@p6rt
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@p6rt p6rt commented Sep 28, 2018

From @labster

Golfs to just the top grammar, which is the only one that returns Nil.

grammar Alnum1 {
  token TOP {<alnum>|<alnum>.*}
}
grammar AlnumReversed {
  token TOP {<alnum>.*|<alnum>}
}
grammar Alpha1 {
  token TOP {<alpha>|<alpha>.*}
}
my $rx = rx/^ [<alnum>|<alnum>.*] $/;

my $str="n~";

.say for "=========== <alnum> ==============",
Alnum1.parse($str),
"=========== <alnum> (reversed) ===",
AlnumReversed.parse($str),
"=========== <alpha> ==============",
Alpha1.parse($str),
"=========== Regex ==============",
$str ~~ $rx;

On Fri, Sep 28, 2018 at 7​:19 AM Patrick R. Michaud via RT <
perl6-bugs-followup@​perl.org> wrote​:

The issue doesn't seem to be the underscore, because I get the same result
even when converting the underscore into a letter ('b')​:

$ cat gentb.p6
grammar G0 {
token TOP {<rport>|<ruport>.*}
regex rport { <type>}
rule ruport { <type>}
#token type {<alpha>+}
token type {<alnum>+}
}

grammar G1 {
token TOP {<rport>|<ruport>.*}
regex rport { <type>}
rule ruport { <type>}
token type {<alpha>+}
#token type {<alnum>+}
}
my $str="scbin<foo> bar";
say "=========== <alnum> Example==============";
say G0.parse($str);
say "=========== <alpha> Example==============";
say G1.parse($str);

$ perl6 gentb.p6
=========== <alnum> Example==============
Nil
=========== <alpha> Example==============
「scbin<foo> bar」
ruport => 「scbin」
type => 「scbin」
alpha => 「s」
alpha => 「c」
alpha => 「b」
alpha => 「i」
alpha => 「n」
$

On Fri, Sep 28, 2018 at 02​:26​:41AM -0700, Brent Laabs wrote​:

Are you sure about that? Underscore has been part of the specs
(synopses)
for <alpha> for at least 10 years, probably longer.

"_" ~~ /<alpha>/
「_」
alpha => 「_」

On Thu, Sep 27, 2018 at 7​:52 PM Brandon Allbery <allbery.b@​gmail.com>
wrote​:

"_" is not an alphabetic character. It's allowed in "alnum" because
that
is by intent what is \w in other regex implementations, which includes
"_".

On Thu, Sep 27, 2018 at 10​:47 PM Vijayvithal <
perl6-bugs-followup@​perl.org>
wrote​:

# New Ticket Created by Vijayvithal
# Please include the string​: [perl #​133541]
# in the subject line of all future correspondence about this issue.
# <URL​: https://rt-archive.perl.org/perl6/Ticket/Display.html?id=133541 >

In the attached code, the only difference between the Grammars G0 and
G1
is the defination of token 'type' it is defined as <alpha> in one case
and as <alnum> in another.

Since the string being matched is 'sc_in' both the alpha and alnum
tokens should have captured it. But we see the following result on
execution

=========== <alnum> Example==============
Nil
=========== <alpha> Example==============
「sc_in<foo> bar」
ruport => 「sc_in」
type => 「sc_in」
alpha => 「s」
alpha => 「c」
alpha => 「_」
alpha => 「i」
alpha => 「n」

Perl Version is

This is Rakudo Star version 2018.06 built on MoarVM version 2018.06
implementing Perl 6.c.

--
Vijayvithal
Dyumnin Semiconductors

--
brandon s allbery kf8nh
allbery.b@​gmail.com

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@p6rt
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@p6rt p6rt commented Oct 2, 2018

From jvs@dyumnin.com

This is in conflict with the documentation at https://docs.perl6.org/language/regexes which states

<alpha>Alphabetic characters including _

And

<alnum>\w. <alpha> plus <digit>

In my example.

'_' matches the alpha regex.

As per specifications, Everything that matches alpha should match alnum.
Which in the given example does not.On Sep 28, 2018 8​:22 AM, Brandon Allbery via RT <perl6-bugs-followup@​perl.org> wrote​:

"_" is not an alphabetic character. It's allowed in "alnum" because that is
by intent what is \w in other regex implementations, which includes "_".

On Thu, Sep 27, 2018 at 10​:47 PM Vijayvithal <perl6-bugs-followup@​perl.org>
wrote​:

# New Ticket Created by  Vijayvithal
# Please include the string​:  [perl #​133541]
# in the subject line of all future correspondence about this issue.
# <URL​: https://rt-archive.perl.org/perl6/Ticket/Display.html?id=133541 >

In the attached code, the only difference between the Grammars G0 and G1
is the defination of token 'type' it is defined as <alpha> in one case
and as <alnum> in another.

Since the string being matched is 'sc_in' both the alpha and alnum
tokens should have captured it. But we see the following result on
execution

=========== <alnum> Example==============
Nil
=========== <alpha> Example==============
「sc_in<foo> bar」
ruport => 「sc_in」
type => 「sc_in」
alpha => 「s」
alpha => 「c」
alpha => 「_」
alpha => 「i」
alpha => 「n」

Perl Version is

This is Rakudo Star version 2018.06 built on MoarVM version 2018.06
implementing Perl 6.c.

--
Vijayvithal
Dyumnin Semiconductors

--
brandon s allbery kf8nh
allbery.b@​gmail.com

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@p6rt
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@p6rt p6rt commented Oct 2, 2018

From jvs@dyumnin.com

This issue surfaces because of the token TOP line. If instead of
<rport>|<ruport> only ruport was used the testcase works for both cases. So it is quite
possible that the bug is elsewhere but shows up as a difference between
alpha and alnum.

Regards
Vijay

On Fri, Sep 28, 2018 at 07​:18​:49AM -0700, Patrick R. Michaud via RT wrote​:

The issue doesn't seem to be the underscore, because I get the same result even when converting the underscore into a letter ('b')​:

$ cat gentb.p6
grammar G0 {
token TOP {<rport>|<ruport>.*}
regex rport { <type>}
rule ruport { <type>}
#token type {<alpha>+}
token type {<alnum>+}
}

grammar G1 {
token TOP {<rport>|<ruport>.*}
regex rport { <type>}
rule ruport { <type>}
token type {<alpha>+}
#token type {<alnum>+}
}
my $str="scbin<foo> bar";
say "=========== <alnum> Example==============";
say G0.parse($str);
say "=========== <alpha> Example==============";
say G1.parse($str);

$ perl6 gentb.p6
=========== <alnum> Example==============
Nil
=========== <alpha> Example==============
「scbin<foo> bar」
ruport => 「scbin」
type => 「scbin」
alpha => 「s」
alpha => 「c」
alpha => 「b」
alpha => 「i」
alpha => 「n」
$

On Fri, Sep 28, 2018 at 02​:26​:41AM -0700, Brent Laabs wrote​:

Are you sure about that? Underscore has been part of the specs (synopses)
for <alpha> for at least 10 years, probably longer.

"_" ~~ /<alpha>/
「_」
alpha => 「_」

On Thu, Sep 27, 2018 at 7​:52 PM Brandon Allbery <allbery.b@​gmail.com> wrote​:

"_" is not an alphabetic character. It's allowed in "alnum" because that
is by intent what is \w in other regex implementations, which includes "_".

On Thu, Sep 27, 2018 at 10​:47 PM Vijayvithal <perl6-bugs-followup@​perl.org>
wrote​:

# New Ticket Created by Vijayvithal
# Please include the string​: [perl #​133541]
# in the subject line of all future correspondence about this issue.
# <URL​: https://rt-archive.perl.org/perl6/Ticket/Display.html?id=133541 >

In the attached code, the only difference between the Grammars G0 and G1
is the defination of token 'type' it is defined as <alpha> in one case
and as <alnum> in another.

Since the string being matched is 'sc_in' both the alpha and alnum
tokens should have captured it. But we see the following result on
execution

=========== <alnum> Example==============
Nil
=========== <alpha> Example==============
「sc_in<foo> bar」
ruport => 「sc_in」
type => 「sc_in」
alpha => 「s」
alpha => 「c」
alpha => 「_」
alpha => 「i」
alpha => 「n」

Perl Version is

This is Rakudo Star version 2018.06 built on MoarVM version 2018.06
implementing Perl 6.c.

--
Vijayvithal
Dyumnin Semiconductors

--
brandon s allbery kf8nh
allbery.b@​gmail.com

--
Vijayvithal
Dyumnin Semiconductors

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@p6rt
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@p6rt p6rt commented Oct 2, 2018

From @labster

Actually, if you change it to <ruport>.*|<rport> -- this will work as you
expect. It's a bug that your version doesn't work, of course. It does
seem to involve <alpha> tangentially, but it is unrelated to underscore.

On Mon, Oct 1, 2018 at 6​:17 PM Vijayvithal via RT <
perl6-bugs-followup@​perl.org> wrote​:

This issue surfaces because of the token TOP line. If instead of
<rport>|<ruport> only ruport was used the testcase works for both cases.
So it is quite
possible that the bug is elsewhere but shows up as a difference between
alpha and alnum.

Regards
Vijay

On Fri, Sep 28, 2018 at 07​:18​:49AM -0700, Patrick R. Michaud via RT wrote​:

The issue doesn't seem to be the underscore, because I get the same
result even when converting the underscore into a letter ('b')​:

$ cat gentb.p6
grammar G0 {
token TOP {<rport>|<ruport>.*}
regex rport { <type>}
rule ruport { <type>}
#token type {<alpha>+}
token type {<alnum>+}
}

grammar G1 {
token TOP {<rport>|<ruport>.*}
regex rport { <type>}
rule ruport { <type>}
token type {<alpha>+}
#token type {<alnum>+}
}
my $str="scbin<foo> bar";
say "=========== <alnum> Example==============";
say G0.parse($str);
say "=========== <alpha> Example==============";
say G1.parse($str);

$ perl6 gentb.p6
=========== <alnum> Example==============
Nil
=========== <alpha> Example==============
「scbin<foo> bar」
ruport => 「scbin」
type => 「scbin」
alpha => 「s」
alpha => 「c」
alpha => 「b」
alpha => 「i」
alpha => 「n」
$

On Fri, Sep 28, 2018 at 02​:26​:41AM -0700, Brent Laabs wrote​:

Are you sure about that? Underscore has been part of the specs
(synopses)
for <alpha> for at least 10 years, probably longer.

"_" ~~ /<alpha>/
「_」
alpha => 「_」

On Thu, Sep 27, 2018 at 7​:52 PM Brandon Allbery <allbery.b@​gmail.com>
wrote​:

"_" is not an alphabetic character. It's allowed in "alnum" because
that
is by intent what is \w in other regex implementations, which
includes "_".

On Thu, Sep 27, 2018 at 10​:47 PM Vijayvithal <
perl6-bugs-followup@​perl.org>
wrote​:

# New Ticket Created by Vijayvithal
# Please include the string​: [perl #​133541]
# in the subject line of all future correspondence about this issue.
# <URL​: https://rt-archive.perl.org/perl6/Ticket/Display.html?id=133541 >

In the attached code, the only difference between the Grammars G0
and G1
is the defination of token 'type' it is defined as <alpha> in one
case
and as <alnum> in another.

Since the string being matched is 'sc_in' both the alpha and alnum
tokens should have captured it. But we see the following result on
execution

=========== <alnum> Example==============
Nil
=========== <alpha> Example==============
「sc_in<foo> bar」
ruport => 「sc_in」
type => 「sc_in」
alpha => 「s」
alpha => 「c」
alpha => 「_」
alpha => 「i」
alpha => 「n」

Perl Version is

This is Rakudo Star version 2018.06 built on MoarVM version 2018.06
implementing Perl 6.c.

--
Vijayvithal
Dyumnin Semiconductors

--
brandon s allbery kf8nh
allbery.b@​gmail.com

--
Vijayvithal
Dyumnin Semiconductors

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@JJ
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@JJ JJ commented May 30, 2020

Guess this has not been fixed yet. Although it's not really clear what the issue is.

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@JJ
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@JJ JJ commented Jul 27, 2020

Looking at the definition of the rules:

https://github.com/Raku/nqp/blob/db0c1088fc34e3518052ee441943fdfa7b3dcbb7/src/QRegex/Cursor.nqp#L973-L989

The only difference seems to be the class of characters it accepts. In the second case it's WORD, which I guess includes _. So looking at the last example, I would say it's a problem with ratcheting in alternations.

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@JJ JJ changed the title Grammer bug <alnum> vs <alpha> Grammar bug <alnum> vs <alpha> Jul 27, 2020
@JJ JJ added docs regex and removed docs labels Jul 27, 2020
@JJ
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@JJ JJ commented Jul 27, 2020

This might be a version of #6570 or related to that in some way, since it involves ratcheting and alternation. As a matter of fact, it does not seem to happen for alpha, so it might go a bit deeper than that.

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