Reference ARGoS

NOTE: don't modify the values of the robot attributes. More specifically:

Never write directly into the robot attributes
- robot.proximity[4].angle = 1.67 -- NO!
Never apply operations such as table.sort() to the robot table
- table.sort(robot.proximity, function(a,b) return a.value > b.value end) -- NO!
If you intend to use the values of a robot table, copy that table first:
- myprox = table.copy(robot.proximity)
- table.sort(myprox, function(a,b) return a.value < b.value end)

`robot.base_ground`	The base ground sensor reads the color of the floor. It is a list of 8 readings, each containing a table composed of `value` and `offset`. The value is either 0 or 1, where 0 means black (or dark gray), and 1 means white (or light gray). The offset corresponds to the position read on the ground by the sensor. The position is expressed as a 2D vector stemming from the center of the robot. The vector coordinates are in cm. The difference between this sensor and the `robot.motor_ground` is that this sensor returns binary readings (0 = black/1 = white), while `robot.motor_ground` can distinguish different shades of gray.
`robot.distance_scanner`	The distance scanner is a rotating device with four sensors. Two sensors are short-range (4cm to 30cm) and two are long-range (20cm to 150cm). Each sensor returns up to 6 values every time step, for a total of 24 readings (12 short-range and 12 long-range). Each reading is a table composed of `angle` in radians and `distance` in cm. The distance value can also be -1 or -2. When it is -1, it means that the object detected by the sensor is closer than the minimum sensor range (4cm for short-range, 20cm for long-range). When a sensor returns -2, it's because no object was detected at all. This device is initially off. You need to use the `enable()` function to switch it on. The function `disable` switches it off. The function `set_angle()` locks the device at a specific angle, while `set_rpm(s)` sets the angular speed of the device to `s` (which must be a number). If you want to convert from radians per second to RPMs, apply the following formula: RPM = 30/pi * radsec.
`robot.gripper`	The gripper allows a robot to connect to objects such as boxes and cylinders, or other robots. A robot attached to a passive object can transport it, if it is light enough. To lock the gripper, you use `lock_positive()` or `lock_negative()`. They both do the same job, so you can call the one you prefer. To unlock the gripper (thus releasing the attached object), use `unlock()`.
`robot.id`	A string containing the id of the robot.
`robot.leds`	Sets the color of the robot LEDs. The robot has a total of 13 RGB LEDs. 12 of them are arranged in a ring around the robot body, and one (also called the beacon) is positioned at the top of the robot body. To set the colors of a single LED, use `set_single_color(idx, color)`. `idx` is the number of the LED to set (1-12 for the body LEDs, 13 for the beacon). `color` can be expressed as a string, such as `"red"`, `"green"`, `"blue"`, etc., or as a triplet of numbers `r,g,b`. To set all colors at once, use `set_all_colors(color)`. The `color` parameter works like `set_single_color(idx, color)`.
`robot.light`	The light sensor allows the robot to detect light sources. The robot has 24 light sensors, equally distributed in a ring around its body. Each sensor reading is composed of an `angle` in radians and a `value` in the range [0,1]. The angle corresponds to where the sensor is located in the body with respect to the front of the robot, which is the local x axis. Regarding the value, 0 corresponds to no light being detected by a sensor, while values > 0 mean that light has been detected. The value increases as the robot gets closer to a light source.
`robot.motor_ground`	The motor ground sensor reads the color of the floor. It is a list of 4 readings, each containing a table composed of `value` and `offset`. The value goes from 0 or 1, where 0 means black, and 1 means white. The offset corresponds to the position read on the ground by the sensor. The position is expressed as a 2D vector stemming from the center of the robot. The vector coordinates are in cm. The difference between this sensor and the `robot.base_ground` is that this sensor can distinguish different shades of gray, while `robot.base_ground` returns binary readings (0 = black/1 = white).
`robot.proximity`	The proximity sensors detect objects around the robots. The sensors are 24 and are equally distributed in a ring around the robot body. Each sensor has a range of 10cm and returns a reading composed of an `angle` in radians and a `value` in the range [0,1]. The angle corresponds to where the sensor is located in the body with respect to the front of the robot, which is the local x axis. Regarding the value, 0 corresponds to no object being detected by a sensor, while values > 0 mean that an object has been detected. The value increases as the robot gets closer to the object.
`robot.random`	This table offers a set of functions to draw random numbers from a distribution. Use `bernoulli()` to get either 0 or 1 from a Bernoulli distribution with p=0.5. You can also write `bernoulli(p)` to set a different value for p. Use `exponential(m)` to get a random number from an exponential distribution with mean `m`. Use `gaussian(s)` to get a random number from a Gaussian distribution with standard deviation `s` and zero mean. You can also write `gaussian(s,m)` to set a non-zero mean. Use `uniform()` to get a random number from a uniform distribution in the range [0,1). Alternatively, you can use `uniform(max)` to get a number between 0 and `max`, or `uniform(min,max)` to get a number between `min` and `max`. If you want integer numbers, use the functions `uniform_int(max)` and `uniform_int(min,max)`.
`robot.range_and_bearing`	The range-and-bearing system allows robots to perform localized communication. Localized communication means that a robot, upon receiving data from another robot, also detects the position of the sender with respect to its local point of view. It is important to notice that the range-and-bearing system is not like WiFi. First, because two robots can exchange data only if they are in direct line of sight - if an object is between two robots, the robots can't communicate. Second, because robots that send data can only broadcast it in a limited area - you can't pick who you talk to as you would with an IP address. Third, the robots can exchange only 10 bytes of data. To set the data to broadcast, use `set_data()`. This function accepts input in two forms. You can write `set_data(idx, data)`, and this means that you set the `idx`-th byte to the value of `data`. `data` must be a number in the range [0,255]. Alternatively, you can write `set_data(data)`, where `data` must be a table containing exactly 10 numbers in the range [0,255]. At each time step, a robot receives a variable number of messages from nearby robots. Each message is stored in a table composed of `data` (the 10-bytes message payload), `horizontal_bearing` (the angle between the robot local x axis and the position of the message source; the angle is on the robot's xy plane, in radians), `vertical_bearing` (like the horizontal bearing, but it is the angle between the message source and the robot's xy plane), and `range` (the distance of the message source in cm).
`robot.wheels`	The real robot moves using two sets of wheels and tracks called treels. For simplicity, we treat the treels like normal wheels. To move the robot, use `set_velocity(l,r)` where `l` and `r` are the left and right wheel velocity, respectively. By 'wheel velocity' we mean linear velocity. In other words, if you say `set_velocity(5,5)`, the robot will move forward at 5cm/s. You can get some information about robot motion and wheels, too. `axis_length` is the distance between the two wheels in cm. `velocity_left` and `velocity_right` store the current wheel velocity. `distance_left` and `distance_right` store the linear distance covered by the wheels in the last time step.
`robot.turret`	The foot-bot gripper is attached to a rotating device called the gripper. You can control the gripper by either setting its rotation, or its rotational speed. To set its rotation, you must first call the method `set_position_control_mode()` to switch the gripper to position control mode, and then call `set_rotation(angle)` to rotate the gripper at angle `angle`. Alternatively, you can set the rotational speed by calling `set_speed_control_mode()` first, and then `set_rotation_speed(speed)`. With `set_passive_mode()` you instruct the gripper to be in a state in which, as the robot moves with an object gripped, the turret rotates due to the weight of the gripped object.
`robot.colored_blob_omnidirectional_camera`	This device returns a list of colored blobs, along with their position with respect to the robot center. A colored blob in ARGoS corresponds to an LED. The list of blobs varies in size over time, depending on what the robots sees. To start collecting data, you need to call `enable()`. To stop, call `disable()`.