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This document describes the Oil language. See What is Oil? for the larger context.
It also discusses future work.
ls -lls -l | wc -lOil retains them all. A big difference is that keywords rather than builtins are used for assignment.
Like Python, JS. See Oil language definition.
[[ ]] and []
echo -e and $''
remaining dynamic parsing in shell
arithmetic is still somewhat dynamic -- replaced by Oil expressions
assignment builtins support dynamism, replaced by var and setvar
set, and maybe =Another concept is parsing modes.
shopt -s all:oil # most important thing, turns on many options
if ( ) {
}
echo @array
set x = 1
builtin set -o errexit
equals:
x = 1
equivalent to
const x = 1
This is for Oil as a configuration language.
echo hi
Expression mode in three places:
echo @array
myprog --flag=$f(x, y)
var z = f(x+1, y)
Control FLow:
if grep foo if (foo) {} # replaces if [ -n $foo ]; then
while
for
switch/case -- for translation to C++ like mycpp match/case
Sigils:
Sigil Pairs:
${x} for word evaluation
$(( )) for shell arithmetic is deprecated
$(bare words) for command sub
@(bare words) for shell arrays
@[1 2 3] for typed arrays
@{ } for table literals / embedded TSV
$// for regexes
c'' c"" r'' r"" for strings
:{} for blocks
:() for unevaluated expressions
Table example:
var people = @{
name age:Int
bob 10_000
'andy c' 15_000
}
var people = {name: @(bob 'andy c'), age: @[10_000 15_000]}
Sigil pairs often change the lexer mode.
echo ${myfloat %.3f}
Formatters (like template languages)
echo ${myfloat|json}
var, set, do, func, returnvar x = 1
auto for autovivification:
auto dict['key'] += 1
maybe const. I want that to be compile-time though.
return has to be a keyword and not a builtin because it can take arbitrary data types, e.g.
return {name: 'bob', age: 15}
Later: Data Frames.
backslashes
##
%%%
Mentioned in the last post. This is big!
The use builtin will provide scope.
But take simplified keyword args like Julia.
@ARGV and ARGV
Assignment builtins local, declare, export
TODO: Link HN thread
echoecho simplified
tweaked: eval, trap
read will probably be overhauled, simplified
use, push, repruse is like source with namespaces. I've come up with a good syntax but
the semantics will be tricky, e.g. caching modules.
push appends to an array
repr for debugging TODO: Probably more for debugging.
NOTE: Haven't decided if blocks have parameters or now? Maybe just magic variables.
cd ~/src { echo $PWD } replaces pushd/popd pairs
Shell options have a stack (modernish also has this):
shopt -s errexit {
}
Env is now a builtin and takes a block
env FOO=bar {
}
fork builtin replaces the weird & terminator:
{ echo 1; sleep 1; echo 2; } &
fork { echo 1; sleep 1; echo 2 }
wait builtin replaces ( ), because ( ) is going
cd, env, and shopt Have Their Own StackLike Python's context manager.
wait and fork builtins Replace () and & Syntaxeach { } Runs Processes in Parallel and Replaces xargseach func
each { }
Evaluates to JSON (like YAML and TOML):
server foo {
port = 80
}
And can also be serialized as command line flags.
Replaces anti-patterns:
BEGIN {
end
}
when x {
}
rule foo.c : foo.bar {
cc -o out @srcs
}
Probably use a block format. Compare with Python's optparse.o
See issue.
Haven't decided on this yet.
check {
}
Python and shell both borrow from C. Oil borrows from Python and C.
text over binary
Coprocesses
Data Frames from R
Low Level Bindings for POSIX, Linux, Containers
Find Dialect
Regex Dialect
Bootstrapping: optional static typing
switch/case
match/case -- algebraic data types, replace case statement?
Hejlsberg quote?