I've added shadow versions of many operators that didn't have one. And, I've changed the behavior of various binary operators with more or fewer than 2 arguments to make the shadow and real versions more consistent and to make the behavior more logical in either case. For details, see the additions to NEWS and the new file tests/native_tests/operators.hy, which simultaneously tests shadow and real operators.
Although there are a lot of changes, I've put them all in one commit because they're interdependent.
The bug was a regression that I introduced in #1228.
I've created a new special form named `fn*` that works like the old `fn` (that is, it always creates a `FunctionDef`). Since this is intended only for internal use, like `with*`, I haven't documented it.
* Remove uses of `car` and `cdr` in /hy
* Remove uses of `car` and `cdr` in quote tests
* Remove `car` and `cdr` in favor of `first` and `rest`
I beefed up the documentation and tests for `first` and `rest` while I was at it.
I defined `car` and `cdr` in native_tests.cons so the tests read a bit more naturally.
* with-decorator: Allow a `setv` form as the form to be decorated
This feature is of dubious value by itself, but it's necessary to allow `defn` to create a lambda instead of a `def`.
* Make `fn` work the same as `lambda`
That is, allow it to generate a `lambda` instead of a `def` statement if the function body is just an expression.
I've removed two uses of with_decorator in hy.compiler because they'd require adding another case to HyASTCompiler.compile_decorate_expression and they have no ultimate effect, anyway.
In a few tests, I've added a meaningless statement in `fn` bodies to force generation of a `def`.
I've removed `test_fn_compiler_empty_function` rather than rewrite it because it seems like a pain to maintain and not very useful.
* Remove `lambda`, now that `fn` does the same thing
