hg.stevelosh.com > temperance

src/wam/compiler/8-ui.lisp @ ba96e98a1d54 

Add precompilation of static queries at compile time

Imagine a function like this:

    (defun legal-moves ()
      (query (legal ?who ?move)))

The argument to `query` there is constant, so we can compile it into WAM
bytecode once, when the Lisp function around it is compiled.  Then running the
query doesn't need to touch the Bones compiler -- it can just load the bytecode
from an array and first up the VM loop.

This saves a lot of time (and consing) compared to compiling the same query over
and over at runtime.
author Steve Losh <steve@stevelosh.com>
date Sun, 17 Jul 2016 16:49:06 +0000
parents 6c90a65137d9
children (none) 
(in-package #:bones.wam)

;;;; ,-.  .                 ,-_/     .
;;;;   |  |   ,-. ,-. ,-.   '  | ,-. |- ,-. ,-. ," ,-. ,-. ,-.
;;;;   |  | . `-. |-' |     .^ | | | |  |-' |   |- ,-| |   |-'
;;;;   `--^-' `-' `-' '     `--' ' ' `' `-' '   |  `-^ `-' `-'
;;;;                                            '

;;; The final phase wraps everything else up into a sane UI.

(defun %compile-query-into (storage query)
  (multiple-value-bind (instructions permanent-variables)
      (precompile-query query)
    (optimize-instructions instructions)
    (values permanent-variables
            (render-query-into storage instructions))))

(defun compile-query (wam query)
  "Compile `query` into the query section of the WAM's code store.

  `query` should be a list of goal terms.

  Returns the permanent variables and the size of the compiled bytecode.

  "
  (%compile-query-into (wam-code wam) query))

(defun compile-query-into (storage query)
  "Compile `query` into the given array `storage`.

  `query` should be a list of goal terms.

  Returns the permanent variables and the size of the compiled bytecode.

  "
  (%compile-query-into storage query))


(defun compile-rules (wam rules)
  "Compile `rules` into the WAM's code store.

  Each rule in `rules` should be a clause consisting of a head term and zero or
  more body terms.  A rule with no body is called a fact.

  "
  (multiple-value-bind (instructions functor arity)
      (precompile-rules rules)
    (optimize-instructions instructions)
    (render-rules wam functor arity instructions)))