https://github.com/markmll/tree-meta
This is a verbatim copy of the implementation formerly at https://github.com/lugon/TREE-META
https://github.com/markmll/tree-meta
compiler-compiler compiler-generator meta-compiler
Last synced: about 2 months ago
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This is a verbatim copy of the implementation formerly at https://github.com/lugon/TREE-META
- Host: GitHub
- URL: https://github.com/markmll/tree-meta
- Owner: MarkMLl
- License: gpl-3.0
- Created: 2024-12-01T18:05:59.000Z (6 months ago)
- Default Branch: main
- Last Pushed: 2025-03-04T13:19:54.000Z (3 months ago)
- Last Synced: 2025-03-04T14:22:56.212Z (3 months ago)
- Topics: compiler-compiler, compiler-generator, meta-compiler
- Language: C
- Homepage:
- Size: 101 KB
- Stars: 0
- Watchers: 1
- Forks: 0
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
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README
## Provenance
Between December 1st 2024 and March 4th 2025 this was a placeholder for a copy of the implementation originally at https://github.com/lugon/TREE-META, with no other content.
The original author deleted his repository, and I believed that I had accidentally deleted the copy which I had downloaded. I find, however, that I still have it.
However the files have no definite indication of authorship, no expression of copyright, and no attached license.
Despite indicating here and on the Wikipedia talk page https://en.wikipedia.org/wiki/Talk:TREE-META#Example_implementation_sources that I intended to republish the files, and attempting to contact the author via his only other project on Github (which is empty), I have received no indication of an objection.
I have applied GPL v3 to this repository, since I believe that it is the best way to protect the original author's rights. If anybody can "show cause" that this is inappropriate, please raise it as an issue.
Share and enjoy. MarkMLl.
## Description
This is an implementation of the [TREE-META](https://en.wikipedia.org/wiki/TREE-META)
compiler writing system. This version is based on the version of TREE-META for the
ICL 1900 described in [this manual][1].
## Getting started
After executing `make` in the base directory you should get `tmc` and `tmm`.
`tmc` will use a program written in TREE-META to translate a program in the
object language. For example, if we have the description of a compiler for
language X in the file `X.tm` and a program written in language X that we wish
to compile in the file `foo.X`, then the following
$ ./tmc X.tm foo.X
will use `X.tm` to compile `foo.X` and output the result to `stdout`.
`tmm` is the TREE-META equivalent of the [META II machine][3]. It reads and executes
programs written in its assembly language. It is used to bootstrap the system.
## Bootstrapping
The TREE-META compiler can be written in its own language. The file [treemeta.tm](treemeta.tm)
is a TREE-META program that describes a TREE-META compiler. This compiler translates
TREE-META programs into assembly language for the TREE-META machine (`tmm`).
The bootstrapping process is as follows (this is what the `meta` target of the makefile does):
$ ./tmc treemeta.tm treemeta.tm >treemeta1.tmm
$ ./tmm treemeta1.tmm treemeta.tm >treemeta2.tmm
$ cmp treemeta1.tmm treemeta2.tmm #should succeed, meaning we reached a fixed point
Note that above we "cheated" by already having a compiler to start with (`tmc`).
We used `tmc` to get a compiled version of `treemeta.tm`. Alternatively, we would
have to first somehow (by hand, for example) translate `treemeta.tm` into assembly.
## Differences and extensions
There are some differences with respect to the version of TREE-META described in
[the manual][1].
The arithmetic expressions recognized are similar in syntax and precedence/associativity
to the ones found in the C language. Signed and unsigned arithmetic is supported
through the introduction of new operators. See the annotated grammar at [grammar.txt](grammar.txt)
for precise details on the syntax recognized.
C style comments (`/*...*/`) are automatically recognized in TREE-META programs
and in the input those programs read. They can appear anywhere whitespace can appear.
The stack used for tree-building is cleared after code generation (initiated by `*`).
The top tree will be processed and everything below will be lost. Generally this
is not a problem because a single tree is passed to the code generation phase.
Code generation must be initiated only from the main syntax rule (the one named
after `.META`).
Dumping of trees in DOT format is supported. After building a tree you can use
`**` instead of `*` to cause the generation of a DOT description of the top tree.
You can render the result with [Graphviz](http://www.graphviz.org/) (you can
do it online [here](http://www.webgraphviz.com/) without installing anything).
Here is an example:
$ cat expr.tm
.META PR
PR = EXPRESSION ** ;
EXPRESSION = TERM $('+' TERM :ADD[2] / '-' TERM :SUB[2]) ;
TERM = FACTOR $('*' FACTOR :MULT[2] / '/' FACTOR :DIV[2]) ;
FACTOR = '+' PRIMARY / '-' PRIMARY :MIN[1] / PRIMARY ;
PRIMARY = .ID / .NUM / '(' EXPRESSION ')' ;
ADD /=> .EMPTY ;
SUB /=> .EMPTY ;
MIN /=> .EMPTY ;
MULT /=> .EMPTY ;
DIV /=> .EMPTY ;
.END
$ cat expr.sr
X/2+Y*(Z-7)
$ ./tmc expr.tm expr.sr >expr.dot
$ dot -Tpng expr.dot -o expr.png
and the result:
## References & History
- [Manual for ICL 1900 version of TREE-META by F R A Hopgood][1]
- [A TREE META for the XDS 940 by J. F. Rulifson][2]
- [META II A SYNTAX-ORIENTED COMPILER WRITING LANGUAGE by Dewey Val Schorre][3]
- [The Tree-Meta Compiler-Compiler System: A Meta Compiler System for the Univac 1108 and the General Electric 645][4]
- [Jeff Rulifson discussing Tree Meta at "The Mother of All Demos" (Clip 18)][5]
- [The Mother of All Demos (1968)(Complete video) (the above clip is from around minute 53)][6]
- [The programming languages behind "the mother of all demos"][7]
- [Tree Meta in the On-Line System (NLS)][8]
- Alan Kay about Tree Meta, [here][9] and [here][10]
[1]: http://www.chilton-computing.org.uk/acl/literature/manuals/tree-meta/contents.htm
[2]: http://bitsavers.org/pdf/sri/arc/rulifson/A_Tree_Meta_For_The_XDS_940_Appendix_D_Apr68.pdf
[3]: http://www.ibm-1401.info/Meta-II-schorre.pdf
[4]: https://ntrl.ntis.gov/NTRL/dashboard/searchResults/titleDetail/AD855122.xhtml
[5]: http://web.stanford.edu/dept/SUL/library/extra4/sloan/mousesite/1968Demo.html
[6]: https://www.youtube.com/watch?v=yJDv-zdhzMY
[7]: http://lambda-the-ultimate.org/node/3122
[8]: http://www.dougengelbart.org/pubs/augment-3954.html#4d
[9]: https://en.wikipedia.org/wiki/Talk:TREE-META#Corrections
[10]: http://ibm-1401.info/OtherStories.html#01/09/2013