Return Only Matching Book Title | Dataford Interview Questions

NextRoll stores a large catalog export as newline-delimited book records. Each record contains a title, description, and author separated by |. Given the export and a search word, return the title of the first book whose title, description, or author contains that word as a complete case-insensitive word.

Process records in input order. Return None when no book matches. A word must not match as part of a larger alphanumeric or underscore token. For example, ad does not match advertising.

Formal Specification

Implement find_book_title(books_text, search_word).

books_text is a string containing zero or more records separated by newline characters.
Each non-empty record has the form title|description|author.
Titles, descriptions, and authors do not contain | or newline characters.
search_word is a non-empty string without whitespace.
Return the matching title as a string, or None if no record matches.

Constraints

1 <= len(books_text) <= 10^7
Each non-empty record contains exactly three pipe-separated fields
Titles, descriptions, and authors do not contain | or newline characters
search_word is non-empty and contains no whitespace
Matching is case-insensitive and uses Unicode word-character boundaries
Return the first matching title in input order

Function Signature

def find_book_title(books_text, search_word):

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