Designed by | Robert M. McClure |
---|---|
Developer | Robert M. McClure |
First appeared | 1963[1] |
Dialects | |
Unix dialect (by Douglas McIlroy) | |
Influenced | |
TROL (by Donald Knuth)[2] |
Developer | Douglas McIlroy |
---|---|
First appeared | 1969 |
Filename extensions | .t |
Dialects | |
PDP-7 version, PDP-11 version | |
Influenced by | |
ALGOL 68,[3] B, PL/I, SNOBOL[4] | |
Influenced | |
B, Yacc |
In computing TMG (TransMoGrifier) is a recursive descent compiler-compiler[5] developed by Robert M. McClure and presented in 1965.[6][7][8] TMG ran on systems including OS/360 and early Unix.[9] It was used to build EPL, an early version of PL/I.[9]
Douglas McIlroy ported TMG to an early version of Unix. According to Ken Thompson, McIlroy wrote TMG in TMG on a piece of paper and "decided to give his piece of paper his piece of paper," hand-compiling assembly language that he entered and assembled on Thompson's Unix system running on PDP-7.[10] Thompson used TMG in 1970 as a tool to offer Fortran, but due to memory limitations of PDP-7 ended up creating the B programming language which was much influenced by BCPL.[6]
The recursive descent algorithm of TMG was studied formally by Alexander Birman and Jeffrey Ullman. The formal description of the algorithms was named TMG recognition scheme (or simply TS).[11]
TMG, ... comes later but appears to have not been influenced by the earlier systems [Alick Glennie's 1960 Syntax Machine, Ned Irons 1960 PSYCO compiler, or Brooker and Morris's 1960 Compiler-Compiler].
Some things I have worked on: Languages and compilers: macros, Lisp, PL/I, TMG (a compiler-compiler), regular expressions; influenced Snobol, Altran, C++ ...
Every program for the original PDP-7 Unix system was written in assembly language, and bare assembly language it was—for example, there were no macros. Moreover, there was no loader or link-editor, so every program had to be complete in itself. The first interesting language to appear was a version of McClure's TMG that was implemented by McIlroy. Soon after TMG became available, Thompson decided that we could not pretend to offer a real computing service without Fortran, so he sat down to write a Fortran in TMG. As I recall, the intent to handle Fortran lasted about a week. What he produced instead was a definition of and a compiler for the new language B.
Doug (M. Douglas) McIlroy exercised the right of a department head to muscle in on the original two-user PDP-7 system. Later he contributed an eclectic bag of utilities: tmg for compiler writing, speak for reading text aloud, diff, and join. He also collected dictionaries and made tools to use them: look (v7, after a model by Ossanna), dict (v8), and spell (v7). ... On the tiny PDP-7 the assembler was supplemented by tmg, Doug McIlroy's version of Bob McClure's compiler-compiler. ... V2 saw a burst of languages: a new tmg, ... and Ritchie's first C,
... TMG that runs under OS360 (sic) ... Mike Green took Bob McClure's 7090/7040 version and implemented the compiler-compiler on the 360; ... TMG was the compiler definition tool used by Ken Thompson to write the compiler for the B language on his PDP-7 in 1970. B was the immediate ancestor of C.