awk macro: revise how implicit block works, and name.

* share/txr/stdlib/awk.tl (sys:awk-expander): Check
that :name designates a symbol, and that it isn't nil.
(awk): Move the implicit block to the outermost scope
so it encloses all of the clauses. Default to the
name awk for the block, rather than nil.

* txr.1: Document that the implicit awk block is
called awk by default, and that nil is not allowed
as a block name.

1 files changed, 9 insertions, 1 deletions

diff --git a/txr.1 b/txr.1
index 02f62750..ab72cf29 100644
--- a/txr.1
+++ b/txr.1
@@ -37203,11 +37203,19 @@ form, specifying this symbol as the argument.
 If the
 .code :name
 form is omitted, the implicit block is named
-.codn nil .
+.codn awk .
 
 It is an error for two or more
 .code :name
 forms to appear.
+
+The
+.code :name
+clause must have an argument which is a symbol;
+the symbol
+.code nil
+is not permitted.
+
 .meIP (:let >> { sym | >> ( sym << init-form )}*)
 Regardless of what order they appear in relation to
 other clauses in the same