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Diffstat (limited to 'txr.1')
| -rw-r--r-- | txr.1 | 17 |
1 files changed, 17 insertions, 0 deletions
@@ -30400,6 +30400,23 @@ treat the situation in a satisfactory way using a definition, which effectively then supplies inline code whenever a certain form is used as a place, and that code itself is treated as a place. +.coNP Special variables @, *place-update-expander* @ *place-clobber-expander* and @ *place-delete-expander* +.desc +These variables hold hash tables, by means of which update expanders, +clobber expanders and delete expanders are registered, as associations +between symbols and functions. + +If +.code "[*place-update-expander* 'sym]" +yields a function, then symbol +.code sym +is the basis for a syntactic place. If the expression yields +.codn nil , +then forms beginning with +.code sym +are not syntactic places. (The situation of a clobber accessor or delete +accessor being defined without an update expander is improper). + .SS* Quasiquote Operator Syntax .coNP Macro @ qquote .synb |