This document discusses using Perl to parse human language and summarize currency conversion queries. It provides examples of using regular expressions in Perl 5.10 and grammars in Perl 6 to parse currency queries, extract the currency codes and amounts, and return the conversion rate between currencies by accessing a hash of rates. Gearman is also mentioned as a way to distribute jobs across multiple worker processes to improve scalability.

1. Using text
in search queries
with examples
in Perl 6

2. It is about
understanding
human language

3. It is about
understanding
human language
at a limited scale

5. whoyougle.com

6. Perl
and
Wolfram|Alpha

7. wolframalpha.com

13. Search queries
Italy

14. Search queries
Pisa

15. Search queries
10 miles in km

16. Search queries
exchange rate of USD

17. Search queries
rate of PHP

18. Search queries
100 USD in EUR

19. Search queries
100 £ in €

20. Scanners (parsers)

21. Scanners (parsers)

22. 100 £ in €
Area.pm Length.pm
Calendar.pm Money.pm
Energy.pm Mass.pm
Force.pm
Asking in parallel

23. 100 £ in €
Area.pm Length.pm
Calendar.pm Money.pm
Energy.pm Mass.pm
Force.pm
120.71

24. Perl 5.10
is great for parsing

25. Perl 6
is even more

26. Named captures in
5.10’s regexes

27. Grammars
in Perl 6

28. Examples
in Perl 5.10 (5.12)

29. my $sentence = qr/
^
(?:
$Infolavka::Search::Grammar::how_many s
(?<to> $currency ) s
$Infolavka::Search::Grammar::convert s
(?: (?<amount> $Infolavka::Search::Grammar::number ) s )?
(?<from> $currency )
)|
(?:
(?: (?<amount> $Infolavka::Search::Grammar::number ) s )?
(?<from> $currency ) s
$Infolavka::Search::Grammar::equal
)|
(?:
(?: $rate s )?
(?: (?<amount> $Infolavka::Search::Grammar::number ) s? )?
(?<from> $currency )
(?:
s
(?: $Infolavka::Search::Grammar::convert s )?
(?<to> $currency )
)?
)
$
/xop;

30. (?<amount>
$Search::Grammar::number ) s? )?
(?<from>
$currency)
(?:
s
(?:
$Search::Grammar::convert
s )?
(?<to> $currency )
)?

31. (?<amount>
$Search::Grammar::number ) s? )?
(?<from>
$currency)
(?:
s
(?:
$Search::Grammar::convert
s )?
(?<to> $currency )
)?

32. (?<amount>
$Search::Grammar::number ) s? )?
(?<from>
$currency)
(?:
s
100 £ in €
(?:
$Search::Grammar::convert
s )?
(?<to> $currency )
)?

33. (?<amount> 100
$Search::Grammar::number ) s? )?
(?<from>
$currency) £
(?:
s
(?:
$Search::Grammar::convert in
s )?
)?
(?<to> $currency )
€

34. Examples
in Perl 6

35. grammar TestGrammar {
rule TOP {
^ <sign>? <digit>+ $
}
token sign {
'-' | '+'
}
token digit {
<[0..9]>
}
}

36. grammar TestGrammar {
rule TOP {
^ <sign>? <digit>+ $
}
token sign {
'-' | '+'
}
token digit {
<[0..9]>
}
}

37. grammar TestGrammar {
rule TOP {
^ <sign>? <digit>+ $
}
token sign {
'-' | '+'
}
token digit {
<[0..9]>
}
}

38. while my $string = prompt('> ') {
if TestGrammar.parse($string) {
say "OK";
}
else {
say "Failed";
}
}

39. grammar CurrencyGrammar {
rule TOP {
^ <rate_question> $
}
rule rate_question {
'rate of'
<currency_code>
}
token currency_code {
<[A..Z]> ** 3
}
}

40. my $result = CurrencyGrammar.parse($string);
if $result {
say "OK";
say $<rate_question><currency_code>;
}

41. grammar CurrencyGrammar {
rule TOP {
^ <rate_question> $
}
rule rate_question {
'rate of'? <currency_code>
[<ws> 'to' <ws> <currency_code>]?
}
token currency_code {
<[A..Z]> ** 3
}
}

42. my $result = CurrencyGrammar.parse($string);
if $result {
say "OK";
my ($from, $to) =
$<rate_question><currency_code>;
say "$from -> $to";
}

43. grammar CurrencyGrammar {
rule TOP {
^ <rate_question> $
}
rule rate_question {
'rate of'? <ws> <money>
[<ws> 'to' <currency_code>]?
}
rule money {
[<value> <ws>]? $<code>=(<currency_code>)
}
token value {
<[0..9]>+
}
token currency_code {
<[A..Z]> ** 3
}
}

44. say "OK";
my $value = $<rate_question><money><value> || 1;
my $from = $<rate_question><money><code>;
my $to = $<rate_question><currency_code> || 'EUR';
say "$value, $from -> $to";

45. rule money {
[<value> <ws>]? $<code>=(<currency_code>)
}

46. rule money {
[<value> <ws>]? <code=currency_code>
}

47. my %rate =
EUR => 1,
USD => 0.7564,
LVL => 1.4116,
RUB => 0.02539,
PHP => 0.01676,
UAH => 0.09587
;
my $codes = %rate.keys.join('|');
say $codes;

48. my $value = ~$<rate_question><money><value> || 1;
my $from = $<rate_question><money><code>;
my $to = $<rate_question><currency_code> || 'EUR';
my $ratio = 0 + %rate{~$from} / %rate{~$to};
say $ratio * $value;

49. my $value = ~$<rate_question><money><value> || 1;
my $from = $<rate_question><money><code>;
my $to = $<rate_question><currency_code> || 'EUR';
my $ratio = 0 + %rate{~$from} / %rate{~$to};
say $ratio * $value;
:-/

50. Rakudo Star
comes with
HTTP::Daemon

53. Dispatching jobs
with Gearman

54. gearman.org

56. Originally written in Perl

57. Rewritten in C

58. Clients in
Perl, PHP, Phython,
Java, C# (.NET)

59. Clients in
Perl, PHP, Phython,
Java, C# (.NET),
even MySQL and PostgreSQL

60. Application
Job

61. Application
Job (or task)

62. Application
Job
gearmand

63. Application
Job
gearmand
Job
Worker

64. Application
Job
gearmand
Job Response
Worker

65. Application
gearmand
Worker
Worker
Worker

66. Application
gearmand
gearmand
Worker
Worker

67. Application
Application
gearmand
gearmand
Worker
Worker

68. Workers are scalable

69. Run any number you need

70. Run on remote servers

71. Application only talks with
gearmand server

72. Application only talks with
gearmand server
(one or more)

73. One or more application

74. One or more application
Applications throw jobs

75. One or more job servers

76. One or more job servers
Job servers dispatch jobs

77. One or more workers

78. One or more workers
(clones or different)

79. One or more workers
Workers do jobs

80. One or more workers
Workers do jobs
and may issue new jobs

81. Scalable also means
redundant

82. Really need
Gearman?

83. Really need
Gearman?
No!

84. Use HTTP servers
instead

85. __END__
Andrew Shitov
talks.shitov.ru | andy@shitov.ru