Example of EXISTS CE to help with #8

docs/examples/EXISTS.ipynb

@@ -0,0 +1,166 @@
+{
+ "cells": [
+ {
+ "cell_type": "markdown",
+ "metadata": {},
+ "source": [
+ "# EXISTS Conditional Element\n",
+ "\n",
+ "With exists you can test if a group of patterns is satisfied by at least one set of facts.\n",
+ "\n",
+ "The rule will be fired once.\n",
+ "\n",
+ "Please note that you although you can use MATCH to pattern match between matches inside the EXISTS group, **those matches can't be used as parameters in the RHS of the rule** (because more than one group of patterns can match and we are only firing once). Trying to use the matched field as parameter will result in a **TypeError**.\n",
+ "\n",
+ "This is a direct translation to Experta of [this](https://www.csie.ntu.edu.tw/~sylee/courses/clips/bpg/node5.4.6.html) Clips example about the EXISTS Conditional Element"
+ ]
+ },
+ {
+ "cell_type": "code",
+ "execution_count": 1,
+ "metadata": {},
+ "outputs": [],
+ "source": [
+ "from experta import *"
+ ]
+ },
+ {
+ "cell_type": "code",
+ "execution_count": 2,
+ "metadata": {},
+ "outputs": [],
+ "source": [
+ "class Goal(Fact):\n",
+ " pass\n",
+ "\n",
+ "class Hero(Fact):\n",
+ " name = Field(str)\n",
+ " status = Field(str, default=\"unoccupied\")"
+ ]
+ },
+ {
+ "cell_type": "code",
+ "execution_count": 3,
+ "metadata": {},
+ "outputs": [],
+ "source": [
+ "class KE(KnowledgeEngine):\n",
+ " @DefFacts()\n",
+ " def goal_and_heroes(self):\n",
+ " yield Goal('save-the-day')\n",
+ " yield Hero(name=\"Death Defying Man\")\n",
+ " yield Hero(name=\"Stupendous Man\")\n",
+ " yield Hero(name=\"Incredible Man\")\n",
+ " @Rule(\n",
+ " Goal('save-the-day'),\n",
+ " EXISTS(\n",
+ " Hero(status=\"unoccupied\")\n",
+ " )\n",
+ " )\n",
+ " def save_the_day(self):\n",
+ " print(\"The day is saved\")"
+ ]
+ },
+ {
+ "cell_type": "code",
+ "execution_count": 4,
+ "metadata": {},
+ "outputs": [],
+ "source": [
+ "ke = KE()\n",
+ "ke.reset()"
+ ]
+ },
+ {
+ "cell_type": "code",
+ "execution_count": 5,
+ "metadata": {},
+ "outputs": [
+ {
+ "data": {
+ "text/plain": [
+ "0: save_the_day {InitialFact(), Goal('save-the-day')}"
+ ]
+ },
+ "execution_count": 5,
+ "metadata": {},
+ "output_type": "execute_result"
+ }
+ ],
+ "source": [
+ "ke.agenda"
+ ]
+ },
+ {
+ "cell_type": "code",
+ "execution_count": 6,
+ "metadata": {},
+ "outputs": [
+ {
+ "data": {
+ "text/plain": [
+ "FactList([(0, InitialFact()),\n",
+ " (1, Goal('save-the-day')),\n",
+ " (2, Hero(name='Death Defying Man')),\n",
+ " (3, Hero(name='Stupendous Man')),\n",
+ " (4, Hero(name='Incredible Man'))])"
+ ]
+ },
+ "execution_count": 6,
+ "metadata": {},
+ "output_type": "execute_result"
+ }
+ ],
+ "source": [
+ "ke.facts"
+ ]
+ },
+ {
+ "cell_type": "code",
+ "execution_count": 7,
+ "metadata": {},
+ "outputs": [],
+ "source": [
+ "# TODO: Implement (matches ) function"
+ ]
+ },
+ {
+ "cell_type": "code",
+ "execution_count": 8,
+ "metadata": {},
+ "outputs": [
+ {
+ "name": "stdout",
+ "output_type": "stream",
+ "text": [
+ "The day is saved\n"
+ ]
+ }
+ ],
+ "source": [
+ "ke.run()"
+ ]
+ }
+ ],
+ "metadata": {
+ "kernelspec": {
+ "display_name": "Python 3",
+ "language": "python",
+ "name": "python3"
+ },
+ "language_info": {
+ "codemirror_mode": {
+ "name": "ipython",
+ "version": 3
+ },
+ "file_extension": ".py",
+ "mimetype": "text/x-python",
+ "name": "python",
+ "nbconvert_exporter": "python",
+ "pygments_lexer": "ipython3",
+ "version": "3.4.8"
+ }
+ },
+ "nbformat": 4,
+ "nbformat_minor": 2
+}