QuickHelpReader

Read Microsoft QuickHelp .HLP databases and get the text back out. No DOS, no DOSBox, no copy of QH.EXE needed.

quickhelp show ALANG.HLP MOV

  Title:    Move Data                             Flags: O D I T S Z A P C
  Syntax:   MOV dest,src                                      -none-
  See also: MOVS, MOVSX, MOVZX, MOV Special, LEA, XCHG
  Description:
     Moves the value in the source operand to the destination operand.

Microsoft shipped this format with most of its DOS development tools from the late eighties onwards. HELPMAKE.EXE built the files and the QuickHelp viewer read them, either standalone or from inside an editor. The documentation for a whole generation of Microsoft tools is still sitting in these files, and as far as I can find, nothing written since reads them.

What it can open

Anything whose first two bytes are LN. On my own DOS installation that is:

File	What is in it
ALANG.HLP	the MASM 6.11 assembly language reference, 1,228 topics
ML.HLP, LINK.HLP, CV.HLP	the assembler, linker and CodeView manuals
PWB.HLP, UTILS.HLP	Programmer's WorkBench and the build tools
QB45QCK.HLP, QB45ADVR.HLP	the QuickBASIC 4.5 language reference
BAS7QCK.HLP, BAS7ADVR.HLP	the same for BASIC 7 PDS

Check a file with:

head -c 2 SOMETHING.HLP

If it says LN, this will read it.

This is not the later Windows .HLP format, which is a different thing entirely and has its own tools.

Usage

quickhelp info FILE                 # topic, context and keyword counts
quickhelp list FILE                 # every context name, with its topic number
quickhelp show FILE TOPIC           # one topic, by context name or number
quickhelp show FILE TOPIC --body    # the same, without the viewer's menu bar
quickhelp dump FILE -o DIR          # every topic, one text file each

dump is the one to reach for if you want to grep a manual. The MASM language reference comes out as 1,228 files; the QuickBASIC reference as about 11,500 lines of text with its code examples intact.

Install

pip install -e .

Python 3.9 or newer. No dependencies.

Tests

pytest

The tests that read a real help file skip unless there is one to hand, since Microsoft's cannot be redistributed. Point QUICKHELP_TEST_DIR at a directory of .HLP files to run those too. The rest do not skip: they build a genuine QuickHelp file, Huffman tree and all, so the decoding is covered wherever the tests run.

How well it works

Every LN file I have opens, and the text comes out clean: no control characters left in any line, and code examples reproduced exactly as the manuals print them.

Some things are approximate, and docs/format.md says which:

• A hyperlink's display text is held in a table rather than inline, so a line containing one loses those few characters.
• The first line of a topic is the viewer's menu bar. --body drops it.
• A wrapped heading can pick up one stray character where two records join.

The format

docs/format.md describes the layout: the header and its six sections, the Huffman coding, the keyword dictionary that compresses the text a second time, and the control codes that carry the display layout. It was worked out from the files themselves, and it says where something is a guess rather than a result.

If you want to write your own reader, or port this, start there.

License

Apache 2.0. See LICENSE.