Re-amalgamating and interpreting Janet (tcc-mob)

[CosmicToast]

I was wondering if Janet was sufficiently simple to be interpreted...
So I built a re-amalgamator to distribute janet shell as a single source file to be interpreted by tcc.
Instructions: download janet.h, janet.c, and shell.c.
Place this script (e.g as build.sh) in the same directory and run it.
You get out an executable script named janet that you can place anywhere and run - it will be interpreted and ran on the fly.
Caveat: no dynamic modules, though regular modules work just fine. Also you're limited to the "default" /usr/local/lib library location like this, unless you change the defines manually.
The script:

#!/bin/sh -e

# extract janet.h include location from janet.c
# we skip the include line itself using %%, which matches any line
csplit -f janet.c. -n1 -s janet.c '/janet.h/' '%%'
# we need this header to be able to execute it directly
# dynamic modules will not work with this so let's disable them
echo '#!/usr/bin/env -S tcc -DJANET_NO_DYNAMIC_MODULES -w -run' > head
# strip out any other mentions of janet.h and assemble the script
cat head janet.c.0 janet.h janet.c.1 shell.c |
	grep -v 'janet\.h' > janet
chmod +x janet

# clean up
rm -f janet.c.* head

It actually runs quite fast and can run some "real" scripts (again, as long as there are no native modules).
The startup time is essentially instant, my native optimized build runs janet -e (quit) in 9.12ms, while the tcc-interpreted one does the same in 95.39ms.
I find it to be a rather good sign in general when a program written in C (let alone an entire language) can be built by something like tcc, let alone interpreted, so this was a fairly cool ~30m experiment.

[sogaiu]

Looks neat!

Locally I didn't quite get it to work due to header file issues:

$ ./janet
In file included from ./src/core/abstract.c:34:
./src/core/abstract.c:34: error: include file 'stdatomic.h' not found

$ find /usr/include | grep stdatomic.h
/usr/include/c++/12/stdatomic.h

Will try again when I'm more awake (^^;

[CosmicToast]

There should be a stdatomic.h that's distributed with tcc, which it should automatically find if it's been installed correctly.
The above snippets suggests it hasn't.
You can always try building it by hand (something like ./configure --prefix=/usr/local, make sure it's actually appropriate for your system, then make and make install).
The result should do it just fine.

[sogaiu]

Thanks for the tips.

I'm using a packaged tcc on an Ubuntu machine, so possibly that's a factor.

I tried compiling from source I got from here, but the tail end of the output was:

make[1]: Entering directory '/home/user/src/tcc-0.9.27/lib'
../tcc -c libtcc1.c -o libtcc1.o -B..
../tcc -c alloca86_64.S -o alloca86_64.o -B..
../tcc -c alloca86_64-bt.S -o alloca86_64-bt.o -B..
../tcc -c va_list.c -o va_list.o -B..
../tcc -c bcheck.c -o bcheck.o -B..
bcheck.c:738: error: '__malloc_hook' undeclared
make[1]: *** [Makefile:64: bcheck.o] Error 1
make[1]: Leaving directory '/home/user/src/tcc-0.9.27/lib'
make: *** [Makefile:230: libtcc1.a] Error 2

Some searching suggests there was some change to glibc some time back.

May be it's another case of Mr. Bellard's software bitrotting...

I guess I'll do some more digging :)

[sogaiu]

Looks like getting source from https://repo.or.cz/tinycc.git works out better.

$ time ./janet -e "(quit)"

real	0m0.143s
user	0m0.111s
sys	0m0.032s

I tried it out on some multi-threaded code and sometimes get:

Segmentation fault (core dumped)

or:

C runtime error at line 629 in file ./src/core/gc.c: invalid janet_sfree

Hmm, may be jane or jean could work as names...

[CosmicToast]

For fun I tried running it on MacOS... it was failing to handle JANET_THREAD_LOCAL, so I added the JANET_SINGLE_THREADED define, at which point I started getting the same runtime error you're seeing.
I'm going to guess that's a tcc moment.