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| author | Kaz Kylheku <kaz@kylheku.com> | 2021-04-24 10:54:29 -0700 |
|---|---|---|
| committer | Kaz Kylheku <kaz@kylheku.com> | 2021-04-24 10:54:29 -0700 |
| commit | 4e32c272c818c01577f42a63e09b01f8b6257fe4 (patch) | |
| tree | 687e058d52c4e685f1a4543bb99e53a9a0336e31 /share | |
| parent | e186650c97103dd3c54621af7f7e2ab5ac07a70a (diff) | |
| download | txr-4e32c272c818c01577f42a63e09b01f8b6257fe4.tar.gz txr-4e32c272c818c01577f42a63e09b01f8b6257fe4.tar.bz2 txr-4e32c272c818c01577f42a63e09b01f8b6257fe4.zip | |
compiler: optimize zero and one item quasiliterals.
* share/txr/stdlib/compiler.tl (expand-quasi): Do not emit
sys:fmt-join call unconditionally. If expand-quasi yields
a list of one expression, we can just yield that expression.
If the list is empty, we can yield a mutable empty string.
(That case will not arise via `` because that converts to ""
at read time, but code that generates quasiliteral syntax
might have an empty case, and expect a mutable string in
all cases).
Diffstat (limited to 'share')
| -rw-r--r-- | share/txr/stdlib/compiler.tl | 5 |
1 files changed, 4 insertions, 1 deletions
diff --git a/share/txr/stdlib/compiler.tl b/share/txr/stdlib/compiler.tl index baf5985f..a395347d 100644 --- a/share/txr/stdlib/compiler.tl +++ b/share/txr/stdlib/compiler.tl @@ -1828,7 +1828,10 @@ (defun expand-quasi (form) (let ((qa (expand-quasi-args form))) - ^(sys:fmt-join ,*qa))) + (cond + ((cdr qa) ^(sys:fmt-join ,*qa)) + (qa (car qa)) + (t '(mkstring 0))))) (defun expand-dohash (form) (mac-param-bind form (op (key-var val-var hash-form : res-form) . body) form |