pymdl

MDL, in PythonThe language of The MDL Programming Language and The MDL Programming Environment, running today

Software architecture, design and engineering by Nicholas J. Kisseberth.

An implementation of MDL in Python, with debugging tools, a library system, native and historical compilers, an assembler, and a PDP-10 emulator. ITS release 55 and Tenex release 105 personalities.

Read the book The 1979 manual

The language of the manuals

The book adapts The MDL Programming Language (Galley & Pfister, 1979) and The MDL Programming Environment (Lebling, 1980). Both source manuals are included for comparison. pymdl provides ITS release 55 and Tenex release 105 personalities, defaulting to 55. Measurements on MDL 55 help resolve questions the manuals leave open.

The era's own tools, running

pymdl runs archived MDL source for the MUDBUG debugging tools, library system, compiler, and assembler. A manifest records each file's provenance, and changes to the compiler sources are documented. The book describes the tests and compiler measurements used to check their behavior.

A PDP-10 when the era needs one

pymdl includes a PDP-10 emulator for historical machine code and code produced by MIT's compiler. Registered Python peers can run selected routines without the emulator. The book explains which execution path a compiled call takes.

Documentation

One book written around the implementation, and the two era manuals it reproduces.

pymdl · the manual

The pymdl book

38 chapters and 10 appendices: pymdl itself, the language as pymdl has it, the environment, and the parts no era manual could describe. Fenced mdl examples are run as tests.49 pages
MIT LCS · May 1979

The MDL Programming Language

Galley and Pfister's language manual for releases 55 (ITS) and 105 (Tenex), transcribed in full: 24 chapters and 9 appendices. The final authority on what the era said.36 pages
MIT LCS · May 1980

The MDL Programming Environment

Lebling's second manual, the one the language manual defers to: the package system, the EDITor, TRACE and the monitors, the library system, the compiler and the assembler.12 pages