Thoughts Rules Engine

Thoughts is a lightweight rules engine.

How To Use:

Add a .json file that contains your rules:

[ { "when": "hello", "then": {"#output": "hello, world!"} } ]

Import the engine

from thoughts.rules_engine import RulesEngine

Start a new engine and load the rule file above

engine = RulesEngine() engine.load_rules("rules.json")

Alternatively, you can create a manual rule without loading a file

rule = {"when": "what time is it", "then": {"#output": "time to get a new watch"}} engine.add_rule(rule)

Define and run assertions

assertion = "hello" engine.run_assert(assertion)

Assertions will match the "when" portion of rules, based on a unification algorithm:

• Strings will match direct string matches, "when": "hello" will match "hello"
• Strings will match using variables, "when": "my dog is ?name" will match "my dog is fido"
• Dictionaries will match a dictionary, "when": {"name": "fido"} will match {"name": "fido"}

If the assertion matches, the "then" portion will fire

Rules will "forward chain" - the "then" portion of rules will cause the engine to match against rules

[ { "when": "hello", "then": {"user-intent": "greet"} },

{   "when": {"user-intent": "greet"},
    "then": {"#output": "hello, world"}
}

]

You can have more than one command (action) in the "then" portion

{ "when": "hello", "then": [{"#output": "hello there"}, {"#output": "nice to meet you"}] }

You can store "item" knowledge (facts)

{"item": "user", "name": "jeremy", "dog": "fido"}

You can reference the items (facts) and their properties in your rules,

using $itemname.property syntax

{"when": "what is my name", "then": [{"#output": "your name is $user.name"} }

Commands

You can use commands in the "then" portion of your rules. The engine will run the commands if the "when" portion matches.

In this version, only three commands are available

#output

• Behavior: Will echo the text to the console (using print)
• Example: {"#output": "hello, world"}
• Optional: specifiy a "rate" to slow output the contents to the console

#prompt

• Behavior: Will ask for input and store into an item
• Example: {"#input": "what is your name", "into": "username"}

#read-rss

• Behavior: Will read the specified rss feed into an item
• Example: {"#read-rss": "https://rss-feed.rss", "into": "rss"}

Examples

read an rss feed and output it to the console at a readable rate

[ {"when": "rss digg.top", "then": [{"#read-rss": "$?feed", "into": "rss"}, {"#output": "$rss.title", "rate": 0.0225}] },

{"item": "digg", "top": "https://digg.com/rss/top.rss"}

]