zc: add the defer statement

defer expr; and defer { ... } register code that runs when the enclosing
block ends: at the end of the block, and at return, break and continue
that leave it. the tokens are kept at the defer and compiled again at each
exit (block_close, body, kw_return, kw_break, kw_continue), newest first,
before the block's variables are released, so the analyzer sees a deferred
rt.free(p) as the transfer of p where it runs. names mean what they meant
at the defer; values are read when it runs. return, break and continue
inside a deferred statement are errors, reported once. works in unchecked
code and closures (own base per function context).

1 files changed, 1 insertions, 0 deletions

diff --git a/src/compiler/setup.zc b/src/compiler/setup.zc
index 4986fc3..1d8ce6f 100644
--- a/src/compiler/setup.zc
+++ b/src/compiler/setup.zc
@@ -110,6 +110,7 @@ int zc_tables() {
 	add_kw("switch", kw_switch, F_STMT);
 	add_kw("break", kw_break, F_STMT);
 	add_kw("continue", kw_continue, F_STMT);
+	add_kw("defer", kw_defer, F_STMT);
 	add_kw("return", kw_return, F_STMT);
 	add_kw("unchecked", kw_unchecked, F_STMT);
 	add_kw("asm", kw_asm, F_STMT | F_EXPR);