Black Perl

"Black Perl" is a code poem written using the Perl programming language. It was posted anonymously to Usenet on April 1, 1990, and is popular among Perl programmers as a piece of Perl poetry. Written in Perl 3, the poem is able to be executed as a program.

"Black Perl" has been discussed in several scholarly works,  and is considered an example of generative literature, a genre of electronic literature.

Attribution
When posted to the  newsgroup the poem was attributed to "a person who wishes to remain anonymous". Sharon Rauenzahn (née Hopkins), another Perl poet, has been suspected to be the author but has since denied the claim.

Result of program execution
When executed, "Black Perl" exits on line one, upon reaching the function exit. The remaining lines are parsed by the Perl interpreter but never actually executed. The program produces no output.

Though it will not parse under Perl 5, multiple independent updates to "Black Perl" to make it parsable in Perl 5 have been published.