## makelib timestamp semantics.
# Compiled by:
# src/app/makelib/paths/srcpath.sublib## "Programs must be written for people
## to read, and only incidentally for
## machines to execute."
##
## -- Abelson and Sussman
package timestamp {
# =========
#
Timestamp
= NO_TIMESTAMP
| TIMESTAMP time::Time # time is from src/lib/std/time.pkg ;
ancient = TIMESTAMP (time::zero_time);
# We consider a target good if it has the same time stamp
# as the source. A target that isn't there is never good,
# and if there is a target but no source, then we assume the
# target to be ok.
#
fun needs_update { target => NO_TIMESTAMP, ... } => TRUE;
needs_update { source => NO_TIMESTAMP, ... } => FALSE;
needs_update { source => TIMESTAMP st,
target => TIMESTAMP tt
}
=>
time::compare (st, tt) != EQUAL;
end;
fun last_file_modification_time filename
=
TIMESTAMP (winix__premicrothread::file::last_file_modification_time filename)
except
_ = NO_TIMESTAMP;
# winix__premicrothread is from src/lib/std/winix--premicrothread.pkg fun set_last_file_modification_time (filename, NO_TIMESTAMP)
=>
();
set_last_file_modification_time (filename, TIMESTAMP timestamp)
=>
winix__premicrothread::file::set_last_file_modification_time (filename, THE timestamp);
end;
fun max (TIMESTAMP t, TIMESTAMP t')
=>
TIMESTAMP if (time::(<) (t, t') ) t';
else t; fi;
max _
=>
NO_TIMESTAMP;
end;
fun to_string NO_TIMESTAMP => "none";
to_string (TIMESTAMP timestamp) => time::to_string timestamp;
end;
};
## (C) 1999 Lucent Technologies, Bell Laboratories
## Author: Matthias Blume (blume@kurims.kyoto-u.ac.jp)