Gensym (Generate Symbols) is an old library for generating unique
symbols (atoms). Such symbols are generated from a base atom which gets
a sequence number appended. Of course there is no guarantee that
catch22 is not an already defined atom and therefore one must be aware
these atoms are only unique in an isolated context.
The SWI-Prolog gensym library is thread-safe. The sequence numbers are
global over all threads and therefore generated atoms are unique over
- gensym(+Base, -Unique)
- Generate <Base>1, <Base>2, etc atoms on each subsequent call.
Note that there is nothing that prevents other parts of the
application to `invent' the same identifier. The predicate
gensym/2 is thread-safe in the sense that two threads generating
identifiers from the same Base will never generate the same
- See also
- - uuid/1, term_hash/2, variant_sha1/2 may be used to
generate various unique or content-based identifiers
- Reset gensym for all registered keys. This predicate is available
for compatibility only. New code is strongly advised to avoid the
use of reset_gensym or at least to reset only the keys used by your
program to avoid unexpected side effects on other components.
- Restart generation of identifiers from Base at <Base>1. Used to make
sure a program produces the same results on subsequent runs. Use