For basic operations, Indigo has its own Programming scheme, that uses Triggers.  A trigger is a status change on a device.  Here is the list of triggers that Indigo, has built-in.  This is not a complete list of Indigo’s triggers, since 3rd party programmers can add their own triggers…  But it gives you a basic understanding of what triggers are available:

Value	Description
ActiveZone	monitor the sprinkler’s activeZone to become =, !=, or any change
AnalogInput	monitor (one of) the analog input(s) available on the device for =, !=, <, >, or any change – stateSelectorIndex is required to be in the range of available inputs
AnalogInputsAll	monitors all of the analog inputs available on the device for any change
BinaryInput	monitor (one of) the binary input(s) to become true, false, or any change – stateSelectorIndex is required to be in the range of available inputs
BinaryInputsAll	monitors all of the binary inputs available on the device for any change
BinaryOutput	monitor (one of) the binary output(s) to become true, false, or any change – stateSelectorIndex is required to be in the range of available outputs
BinaryOutputsAll
BrightnessLevel	monitor the brightness level of a device for =, !=, <, >, and any change
HumidityInput	monitor (one of) the humdity sensor(s) available on the device for =, !=, <, >, and any change – stateSelectorIndex is required to be in the range of available inputs
HumidityInputsAll	monitors all of the humidity sensors available on the device for any change
HvacCoolerIsOn	monitor the thermostat for any time the air conditioning turns on, off, or has any change (coolIsOn is the current compressor state)
HvacFanIsOn	monitor the thermostat for any time the fan turns on, off, or has any change (fanIsOn is the current fan state)
HvacFanMode	monitor the fanMode of the thermostat for any change
HvacFanModeIsAlwaysOn	monitor the fanMode of the thermostat for a change to/from kFanMode.AlwaysOn
HvacFanModeIsAuto	monitor the fanMode of the thermostat for a change to/from kFanMode.AutoOn
HvacHeaterIsOn	monitor the thermostat for any time the heater turns on, off, or has any change (heatIsOn is the current heater state)
HvacOperationMode	monitor the hvacMode of the thermostat for any change
HvacOperationModeIsAuto	monitor the hvacMode of the thermostat for a change to/from kHvacMode.HeatCoolOn
HvacOperationModeIsCool	monitor the hvacMode of the thermostat for a change to/from kHvacMode.CoolOn
HvacOperationModeIsHeat	monitor the hvacMode of the thermostat for a change to/from kHvacMode.HeatOn
HvacOperationModeIsOff	monitor the hvacMode of the thermostat for a change to/from kHvacMode.Off
HvacOperationModeIsProgramAuto	monitor the hvacMode of the thermostat for a change to/from kHvacMode.ProgramAuto
HvacOperationModeIsProgramCool	monitor the hvacMode of the thermostat for a change to/from kHvacMode.ProgramCool
HvacOperationModeIsProgramHeat	monitor the hvacMode of the thermostat for a change to/from kHvacMode.ProgramHeat
KeypadButtonLed
OnOffState	monitor the device for a change to/from on/off
SensorInput	monitor (one of) the sensor input(s) available on the device for =, !=, <, >, or any change – stateSelectorIndex is required to be in the range of available inputs
SensorInputsAll	monitors all of the sensor inputs available on the device for any change
SetpointCool	monitor the cool setpoint of the thermostat for =, !=, <, >, or any change
SetpointHeat	monitor the heat setpoint of the thermostat for =, !=, <, >, or any change
TemperatureInput	monitor (one of) the temperature sensor(s) available on the device for =, !=, <, >, and any change – stateSelectorIndex is required to be in the range of available inputs
TemperatureInputsAll	monitors all of the temperature sensors available on the device for any change
Zone	monitor (one of) the binary output(s) to become true, false, or any change – stateSelectorIndex is required to be in the range of available outputs

The basic built-in Trigger system is a programming language.  The trigger system is quite impressive , and allows fantastic control over Indigo.

But what if you want to do more…?  More complex triggers and/or develop plugins for Indigo?  Indigo is designed for all levels of Home Automation users, the Beginner, Intermediate, and Expert / Power User.  Indigo supports two more programming languages,  Applescript and Python.

The Python Programming language is highly recommended, over Applescript…  But Applescript does offer some better ease of integrating with your Macintosh & Macintosh applications.

Here’s a secret, Indigo’s triggers even allow you to run embedded Applescript and Python scripts.  So in many cases, you don’t need to develop a plugin.  Just trigger a Python or Applescript, from a trigger action..

But learn Python before you sit down and try to write a Python script for the first time.

This is the Python v2.54 tutorial, which I highly recommend… I wouldn’t start with later versions, simply because v2.5x is the version Indigo currently uses.

http://docs.python.org/release/2.5.4/tut/tut.html

Get comfortable with Python, and then read the Indigo 5 Scripting Tutorial…

http://www.perceptiveautomation.com/wik … g_tutorial

That covers basic Python coding in the Interactive Script Window.

If you decide that you want to progress into developing your own plugins, the Indigo Plugin Developer’s Guide covers everything you have asked about… What are the XML files, and the structure of a plugin, etc…

http://www.perceptiveautomation.com/wik … ugin_guide