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PDF Processing ​

Pure-Rust PDF text extraction, page counting, and metadata reading. No external tools required — works cross-platform including macOS, Linux, and Windows.

TIP

These functions use the pdf-extract and lopdf Rust crates internally. They work with text-based PDFs. For scanned/image-only PDFs, consider using llm/extract-from-image with vision models instead.

Text Extraction ​

pdf/extract-text ​

Extract all text from a PDF file, concatenated across all pages.

scheme
(pdf/extract-text "invoice.pdf")
; => "Invoice\nDate: 2025-01-15\nAmount: $50.00 USD\n..."

;; Clean up whitespace for LLM processing
(text/clean-whitespace (pdf/extract-text "invoice.pdf"))
; => "Invoice Date: 2025-01-15 Amount: $50.00 USD ..."

pdf/extract-text-pages ​

Extract text from a PDF, returning a list of strings — one per page.

scheme
(pdf/extract-text-pages "report.pdf")
; => ("Page 1 content..." "Page 2 content..." "Page 3 content...")

;; Get text from a specific page
(nth (pdf/extract-text-pages "report.pdf") 0)
; => "Page 1 content..."

;; Process each page separately
(for-each
  (fn (page-text)
    (println (format "Page has ~a words" (text/word-count page-text))))
  (pdf/extract-text-pages "report.pdf"))

Metadata ​

pdf/page-count ​

Return the number of pages in a PDF.

scheme
(pdf/page-count "report.pdf")
; => 12

pdf/metadata ​

Return a map of PDF metadata fields. Always includes :pages; other fields (:title, :author, :subject, :creator, :producer) are included when present in the PDF.

scheme
(pdf/metadata "document.pdf")
; => {:author "John Doe" :pages 5 :producer "LibreOffice" :title "Quarterly Report"}

;; Access individual fields
(get (pdf/metadata "document.pdf") :title)
; => "Quarterly Report"

(get (pdf/metadata "document.pdf") :pages)
; => 5

Example: Receipt Processor ​

Combine PDF extraction with LLM structured extraction to build an intelligent document processor:

scheme
;; Extract text from a PDF invoice
(define text (text/clean-whitespace (pdf/extract-text "invoice.pdf")))
(define pages (pdf/page-count "invoice.pdf"))
(println (format "Extracted ~a chars from ~a page(s)" (string-length text) pages))

;; Use LLM to classify and extract structured data
(llm/auto-configure)
(define result
  (llm/extract
    {:isReceipt {:type :boolean :description "Is this a receipt or invoice?"}
     :vendor {:type :string :description "The seller/merchant name"}
     :amount {:type :string :description "Total amount with currency"}
     :date {:type :string :description "Invoice date in YYYY-MM-DD format"}}
    text))

(println (format "Vendor: ~a" (get result :vendor)))
(println (format "Amount: ~a" (get result :amount)))

See the full GLaDOS receipt processor example for a complete implementation.