Nom is a sed-inspired language for parsing text patterns, formats, and
context-free and context-sensitive languages. Nom is a simple language
for parsing simple languages, and for that reason it gives rise to all
sorts of self translation possibilities, not just the standard
"self-hosting" compiler.
In fact Nom gives rise to some interesting identies: if T is a function
or relation (in this case a nom translation script) then
T(X) = x
where X is a nom script and x is an equivalent script or source code
in some other language (eg Perl, Lua, Rust). Logically, the following
holds
T(T) = t
So the translation script can be run on itself. Also
t(T) = t
So when the translated translator is run on the original script it produces
itself. Writing all this in Unix-speak as regards pep/nom, we have, in the
case of Lua
pep -f nom.tolua.pss nom.tolua.pss > nom.tolua.lua
cat nom.tolua.pss | lua nom.tolua.lua > nom.tolua.again.lua
diff nom.tolua.lua nom.tolua.again.lua
The last diff produces no output because the files are the same.
- www.nomlang.org/doc/ documentation
- www.nomlang.org/tr/ translation scripts
- www.nomlang.org/object/ c implementation of pep interpreter
In fact Nom gives rise to some interesting identies: if T is a function or relation (in this case a nom translation script) then T(X) = x where X is a nom script and x is an equivalent script or source code in some other language (eg Perl, Lua, Rust). Logically, the following holds T(T) = t So the translation script can be run on itself. Also t(T) = t So when the translated translator is run on the original script it produces itself. Writing all this in Unix-speak as regards pep/nom, we have, in the case of Lua pep -f nom.tolua.pss nom.tolua.pss > nom.tolua.lua cat nom.tolua.pss | lua nom.tolua.lua > nom.tolua.again.lua diff nom.tolua.lua nom.tolua.again.lua The last diff produces no output because the files are the same.