Altera Hardware Description Language (AHDL) Language Reference Manual
Many years ago, back when Altera shipped Max+PlusII software with real printed manuals, an AHDL language reference was included. Many of the Altera MegaFunctions still use AHDL and there are many customer designs which still make use of this language.
The official title of the original manual was "Altera MAX+PLUS® II AHDL" which was mostly a Language Reference Manual, but also made references to the old Max+PlusII software. Although most people no longer care about Max+PlusII, having access to the original language definition is still useful.
It appears this manual has never been made available in an electronic format, so attached you will find a copy. It was scanned at 300dpi greyscale (except for the front and back covers) and has been OCR'ed by Acrobat 9.x, making it searchable.