New alet macro.

* lisplib.c (place_set_entries): Add alet symbol to autoload
list for place.tl.

* share/txr/stdlib/place.tl (alet): New macro.

* txr.1: Documented alet.

1 files changed, 25 insertions, 0 deletions

diff --git a/txr.1 b/txr.1
index d4a42a72..06d4e775 100644
--- a/txr.1
+++ b/txr.1
@@ -27812,6 +27812,31 @@ to symbol macros. In addition, unlike
 also reduces to symbol macros those bindings which
 are initialized by symbol expressions (values of variables).
 
+.coNP Macro @ alet
+.synb
+.mets (alet >> ({( sym << init-form )}*) << body-form *)
+.syne
+.desc
+The macro
+.code alet
+("atomic" or "all") is a stronger form of the
+.code slet
+macro. The transformation of any of the bindings to symbol macros takes place
+under the same conditions as under
+.codn slet .
+However,
+.code alet
+imposes the restriction that all the bindings must be transformed
+to symbol macros, or not at all.
+
+The
+.code alet
+macro can be used to avoid introducing temporary variables in situations when
+it is suspected that the initializing forms for the variables have side
+effects through which they affect each others' evaluations. The suspicion is
+lifted if the all initializing forms (after expansion) are constants, or
+accesses to symbols.
+
 .coNP Macro @ define-accessor
 .synb
 .mets (define-accessor < get-function << set-function )