yap(1) prolog interpreter and compiler


yap [options] filename


yap is a prolog interpreter and compiler.

In its basic form, yap starts an interactive Prolog interpreter. When restoring a saved state, yap will allocate the same amount of memory as that in use when the state was saved, unless a different amount is specified by flags in the command line. By default, yap restores the file startup from the current directory or from the yap library.

See the yap manual for how to use yap for writing Prolog scripts.


Print a short error message.
-s n
Allocate nFP K bytes for local and global stacks.
-h n
Allocate n K bytes for heap and auxiliary stacks
-t n
Allocate n K bytes for the trail stack
-l yap-file
Compile the Prolog file yap-file before entering the top-level.
-L yap-file
Compile the Prolog file yap-file and then halt. This option is useful for implementing scripts.
-g goal
run the goal goal before top-level. The goal is converted from an atom to a Prolog term.
-z goal
run the goal goal as top-level. The goal is converted from an atom to a Prolog term.
-b boot-file
Boot code is in Prolog file boot-file. The filename must define the predicate '$live'/0.
-c ip-host port
Connect standard streams to host ip-host at port port.
Restore state saved in the given file.
Separator for arguments to Prolog code. These arguments are visible through the unix/1 built-in.


Yap usually boots from a saved state. The saved state will use the default installation directory to search for the YAP binary unless you define the environment variable YAPBINDIR.
Yap always tries to find saved states from the current directory first. If it cannot it will use the environment variable YAPLIBDIR, if defined, or search the default library directory.
Yap will try to find library files from the YAPSHAREDIR/library directory.


Yap was written by R. Lopes, L.Damas, V. Santos Costa.

This manual page was compiled by Ralf Treinen <[email protected]> from the Yap manual for the Debian project (but may be used by others).


Since this manpage is derived from the yap manual it is subject to the licence of the yap manual:

Permission is granted to make and distribute verbatim copies of this manual provided the copyright notice and this permission notice are preserved on all copies.

Permission is granted to copy and distribute modified versions of this manual under the conditions for verbatim copying, provided that the entire resulting derived work is distributed under the terms of a permission notice identical to this one.

Permission is granted to copy and distribute translations of this manual into another language, under the above conditions for modified versions.