txr: identify output repeat vars at parse time

Up to now the @(repeat) and @(rep) directives have scanned
their interior to find output variables. We now hoist that
into the parser; the variables are found up-front and
integrated into the abstract syntax.

This work anticipates doing a more proper job of identifying
free variables in Lisp expressions.

* match.c (extract_vars): Delete static this function here.
It moves into parser.y.
(extract_bindings): Don't call extract_vars to obtain the
variables occurring in the repeat body. Get it as a new
argument, occur_vars.
(do_output_line, do_repeat): Extract the new occur_vars
element of the abstract syntax node and pass it to
extract_bindings.

* parser.y (extract_vars): New static function, moved here
from match.c.
(repeat_rep_helper): Scan over each of the repeat subclauses
with extract vars. Catenate the resulting lists together and
pass through uniq to squash repeated symbols. Then add the
resulting vars as a new element of the returned syntax node.

0 files changed, 0 insertions, 0 deletions