diff options
Diffstat (limited to 'txr.1')
| -rw-r--r-- | txr.1 | 30 |
1 files changed, 26 insertions, 4 deletions
@@ -44223,8 +44223,30 @@ reduces bindings initialized by constant expressions to symbol macros. In addition, unlike .codn rlet , .code slet -also reduces to symbol macros those bindings which -are initialized by symbol expressions (values of variables). +also reduces to symbol macros those bindings whose initializing +expressions are simple references to lexical variables. + +.TP* Examples: + +.verb + ;; reduces to let + (slet ((a (list x y))) + a) + + ;; b is a free variable, so this is also let + (slet ((a b)) + a) + + ;; b is lexical, so a becomes a symbol macro + ;; the (slet ...) form becomes b. + (let (b) + (slet ((a b)) + a)) + + ;; a becomes symbol macro; form transforms to 1. + (slet ((a 1)) + a) +.brev .coNP Macro @ alet .synb @@ -44237,7 +44259,7 @@ The macro .code slet macro. All bindings initialized by constant expressions are turned to symbol macros. Then, if all of the remaining bindings are -all initialized by symbol expressions, they are also turned to +all initialized by lexical variables, they are also turned to symbol macros. Otherwise, none of the remaining bindings are turned to symbol macros. @@ -44249,7 +44271,7 @@ others' evaluations. In this situation .code alet still propagates constants via symbol macros, and can eliminate the remaining temporaries if they can all be made symbol macros for -existing variables: i.e. there doesn't exist any initialization form +existing lexicals: i.e. there doesn't exist any initialization form with interfering side effects. .coNP Macro @ define-accessor |