The most unique feature is the type system which allows you to both model domain problems effectively and guarantee consistency. This reduces a huge number of bugs in compile-time.
Smalltalk/X can fileout packages as C projects that are then compiled by C compiler. But AFAIK this was never meant to be used as JIT and is primarily an deployment mechanism and non-ancient versions use in-process code generator implemented in Smalltalk as JIT backend.
There are Common Lisp implementations that support similar mechanism of generating C code (ECL, Kyoto CL...), but I don't think any of then compiles C into .so which then gets dlopened right away as poor-mans JIT.
KCL generates .c files and compiles those to .o object files. I played with this year ago (via the descendant GCL: GNU Common Lisp). The load function handles object files, like COFF or whatever. It's reminiscent of the Linux kernel modules.
When KCL compiles a lambda expression, it generates a C file called "gazonk.lsp" and compiles that.
(The above paper report is a little confusing; in some places it claims that an object file has a .o suffix, but then with regard to this gazonk implicit name, it claims that the fasl file is gazonk.fasl.)
Example with GCL: compile individual function to C, compile it with C to a .o (for example on my 32bit ARM it is a elf32-littlearm file) file and then load it:
>(defun foo (a) (* a 42))
FOO
>(compile 'foo)
Compiling /tmp/gazonk_24158_0.lsp.
End of Pass 1.
End of Pass 2.
OPTIMIZE levels: Safety=0 (No runtime error checking), Space=0, Speed=3
Finished compiling /tmp/gazonk_24158_0.lsp.
Loading /tmp/gazonk_24158_0.o
start address -T 0x888488 Finished loading /tmp/gazonk_24158_0.o
#<compiled-function FOO>
NIL
NIL
- Blocks (curly brackets and separated by newlines or semicolons):
{ a b; c d }
- Dotted lists, where sometimes the dots can be omitted:
foo.bar.baz
In combination, you can write something like:
for x in [1, 2, 3] {
foo.bar(x + 1, x * 2)
}
Which can be interpreted as 7 lists. The top-level list has five items, the last two of which are lists. The last list is a block containing one item, which is a three-item dotted list. The argument list after "bar" is a two-item comma list containing two phrases.
I've implemented this, but I'm not satisfied with it; the corner cases are tricky to understand.
Slack is basically a spiffed-up IRC. Trello is a virtual index card board. Neither is, "designed to merge key features of communications media such as email, instant messaging, wikis, and social networking."
