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Goals

A Paraflow goal represents a desired activity to perform. The activity may be parameterized by data. A goal instance consists of a name and zero or more specific parameter values. Here is an example goal:

!SendMessage(template -> 5039883, recipient -> “joe@gmail.com”)

Goal names are always preceded by the ! symbol.

Each goal instance has a state which typically progresses from Planned, to Active, to Complete. Once a goal instance has reached the Complete state, that goal is considered to be achieved; any subsequent requests to perform the same goal will not result in any further action because it has already been achieved.

Goals to be achieved are created in two ways:

  • Event handlers may create new goals
  • Rules describe how to decompose an existing goal into subgoals

Goal Pattern​

The goal pattern describes:

  • The goals to which it can be applied,
  • Zero or more constraint conditions, and
  • The data context captured for use in the rule body

Goal patterns have the form:

<goal-pattern> := <goal-term> { "," <goal-term> | <data-term> }
<goal-term> :=
    <goal> "(" <pattern-binding> {"," <pattern-binding>} ")"
<data-term> :=
    <table-name> "(" <pattern-binding> {"," <pattern-binding>} ")"

For example,

!processOrder($id), order(id == $id, agent == "ext", $email)

This head matches !processOrder goals if there exists a row in the order table where the id column is equal to the goal’s $id parameter and the agent column is equal to "ext". Further, it captures the value of the email column of that row in a local variable $email that can be used within the rule body.

The pattern binding syntax is described in detail in the Binding section.