expander: bug: atoms in quasiliteral.

Via macros, atoms can sneak into a quasiliteral which then
blow up because they get treated as strings without being
converted.

Example:

  (defmacro two () 2)

  `@(two)xyz` -> ;; error

The expansion produces the invalid form, in which the 2
is subsequently treated as a string.

  (sys:quasi 2 "xyz")

On the other hand, symbol macros don't have this problem:

  (defsymacro two 2)

  `@{two}xyz` -> "2xyz"

The reason is that the (sys:var two) syntax will expand to
(sys:var 2), and not 2.

The straightforward, consistent fix is to ensure that the
first case will also go to (sys:var 2).

* eval.c (expand_quasi): If the expanded form is an atom which
is not a bindable symbol, wrap it in a sys:var.

* tests/012/quasi.tl: Test cases added.
Also adding a compilation test for this file, cribbed from
patmatch.tl.

0 files changed, 0 insertions, 0 deletions