Unable to run nools

Question

Hi I'm working on nools in node.js. When I run this program an error occurred:

throw new Error("Invalid expression '" + expression + "'") Invalid expression 'm.text = ~/^hello(\s*world)?$/' pls help to fix this problem.

Here my Code:

Server.js

var express        =         require("express");
var bodyParser     =         require("body-parser");
var app            =         express();

app.use(bodyParser.urlencoded({
    extended: true
}));

var index = 0;

var nools = require("nools");

var flow = nools.compile(__dirname + "/server/rules.nools");
var Message = flow.getDefined("message");
var session = flow.getSession();

session.matchUntilHalt().then(
    function() {
        //all done!
        console.log("All done!");
    },
    function(err) {
        console.log("Error matchUntilHalt()", err.stack);
    }
);

app.post('/fact', function(req, res) {
    var key = req.body.key;

    console.log("\n" + ++index + " New fact", key);

    var newMsg = new Message(key);

    session.assert(newMsg);

    res.end("All OK");
});

app.get('/', function(req, res) {
    res.end("Watsup! Its " + new Date());
});

app.listen(4000, function() {
    console.log("Started up!");
});

rools.nools

define Message {
    text: '',
    constructor: function(message) {
        this.text = message;
    }
}

//find any message that starts with hello
rule Hello {
    when {
        m: Message m.text = ~/^hello(\s*world)?$/;
    }
    then {
        console.log("Hello rule fired.");
    }
}

//find all messages then end in goodbye
rule Goodbye {
    when {
        m: Message m.text = ~/.*goodbye$/;
    }
    then {
        console.log("Goodbye rule fired.");
    }
}

define Client {
    age: 0,
    constructor: function(age) {
        this.age = age;
    }
}

rule CheckAge {
    when {
        // Multiple conditions in same rule
        c: Client c.age > 30 && c.age < 65
    }
    then {
        console.log("Eligible for loan");
    }
}

Answer 1

Your error is here :

//find any message that starts with hello
rule Hello {
    when {
        m: Message m.text = ~/^hello(\s*world)?$/;
    }
    then {
        console.log("Hello rule fired.");
    }
}

//find all messages then end in goodbye
rule Goodbye {
    when {
        m: Message m.text = ~/.*goodbye$/;
    }
    then {
        console.log("Goodbye rule fired.");
    }
}

the expression that you want to use have a space between = and ~

m: Message m.text = ~/.*goodbye$/;
m: Message m.text = ~/^hello(\s*world)?$/;

change to :

m: Message m.text =~ /^hello(\s*world)?$/;

and

m: Message m.text =~ /.*goodbye$/;

and it will work.