---
name: "yap"
section: "1"
platform: "linux"
package: "yap"
version: "6.2.2-6+b2"
release: "Debian 9 (Stretch)"
platforms: ["linux"]
url: "https://new.carta.tech/yap"
---

# yap(1)

prolog interpreter and compiler

## NAME

yap - prolog interpreter and compiler

## SYNOPSIS

**yap** \[*options*\] *filename*

## DESCRIPTION

**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.

## OPTIONS

- **-?**

  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.*

- **filename**

  *Restore state saved in the given file.*

- **--**

  *Separator for arguments to Prolog code. These arguments are visible* *through the unix/1 built-in.*

## ENVIRONMENT

- **YAPBINDIR**

  *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.*

- **YAPLIBDIR**

  *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.*

- **YAPSHAREDIR**

  *Yap will try to find library files from the YAPSHAREDIR/library directory.*

## SEE ALSO

*The YAP manual is on a debian system available through the info system* *(command info yap), and as a html document through the debian help* *system.*

## AUTHOR

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

*This manual page was compiled by Ralf Treinen \<treinen@debian.org\> from the* *Yap manual for the Debian project (but may be used by others).*

## COPYRIGHT

*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.*