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✏️ Editing: demo_randomsentence.pl

#!/usr/bin/perl
$|++;

use Parse::RecDescent;

my $parser = Parse::RecDescent->new(<<'END_OF_GRAMMAR');

grammar: rule(s) /\Z/ { [ map { $_->[0], $_->[1] } @{$item[1]} ] }

rule: identifier ":" defn ";" { [ $item[1], $item[3] ] }
	| <error>

defn: choice (barchoice)(s?) { [ $item[1], @{$item[2]} ] }

barchoice: "|" choice

choice: item(s)

item: quoted_string | identifier | <error>

quoted_string: /"(.*?)"/s { " ".substr($item[1],1,-1) }

identifier: /[A-Za-z_]\w*/

END_OF_GRAMMAR

(my $parsed = $parser->grammar(join '', <DATA>)) or die "bad parse";

my $top = $parsed->[0];
my %defns = @$parsed;

for (1..5) {
  show($top);
  print "\n----\n";
}

sub show {
  my $defn = shift;
  die "missing defn for $defn" unless exists $defns{$defn};

my @choices = @{$defns{$defn}};
  for (@{$choices[rand @choices]}) {
	## should be a list of ids or defns
	die "huh $_ in $defn" if ref $defn;
	if (/^ (.*)/s) {
	  print $1;
	} elsif (/^(\w+)$/) {
	  show($1);
	} else {
	  die "Can't show $_ in $defn\n";
	}
  }
}

__END__
stanza: stanza exclaim stanza2 | stanza2;
stanza2: sentence comparison question | sentence comparison | comparison
comparison exclaim | address question question sentence;

sentence: sentence sentence2 | sentence2;
sentence2: "The " adjectiveNotHep personNotHep verbRelating "the "
adjectiveHep personHep ". " | "The " personHep verbRelating "the "
adjectiveNotHep ", " adjectiveNotHep personNotHep ". ";

question: question question2  | question2;
question2: ques_start adjectiveHep personNotHep "? " | ques_start
adjectiveNotHep personHep "? ";

comparison: comparison comparison2 | comparison2;
comparison2: "One says '" compNotHep "' while the other says '" compHep
"'. "|
"One thinks '" compNotHep "' while the other thinks '" compHep "'. "|
"They shout '" compNotHep "!' And we shout'" compHep "'. "|
"It's " compNotHep " versus " compHep "! ";

MR SKB