Background

jLogo Programming

Java

Appendices

Updates

Lastly

New TG Features - January 6, 2012

Introduction

Version .0.9.33 of TG has new features that make it easier to use and enhancements that allow you to put together much more interesting applications.

Improved Help

The help directive now supports keywords that are associated with TG's directives, primitive procedures, and editing commands. As a review, prior versions of TG supported a hierarchical-based help. The help command with no input resulted in an overview of the hierarchy being printed. Inputs that have been accepted are:

"tg" which prints an overview of the TG programming environment,
categoryName" which prints a list of things that TG can do which fit in the category, and
item" which prints a description of item.

Now when help is given a keyword, which the help database contains, a list of all things that are tied to the keyword are printed. Figure 1 shows an example of asking for help on io-related stuff.

Figure 1

But... which keywords it knows about is limited. If you try to get help on some keyword and none is available, e-mail us your keyword (bfoitGuy at gmail dot com). We will try to improve TG's keyword vocabulary over time.

New Graphics Pixel Stuff

Name	Input(s)	Description
COLORSUNDER		Outputs a list of the colors under the turtle's image, one member for each unique color.
GETPIXELS	rectList	Outputs an array of pixel values specified by the input rectangleList, a List of four numbers. The first number is the left-most X edge of the rectangle, the second number is the top Y edge of the rectangle, the third number is the width of the rectangle, and the fourth number is the height of the rectangle, e.g., (sentence :leftX :topY :width :height).
SETPIXELS	rectList, pixelArray	Paints the values of pixels in pixelArray onto the area of the graphics canvas specified by rectList. Pixel values are color numbers. A rectList has the form [leftX, topY, width, height].
SHAPEHEIGHT		Outputs the height of the turtle's shape in pixels, the image for its current heading.
SHAPEPIXELS		Outputs a list containing two members. The first is the number of pixels in each row of the turtle's shape. The second is an array containing all of the pixels that make up the shape's image.
SHAPEWIDTH		Outputs the width of the turtle's shape in pixels, the image for its current heading.
STAMP		Paint the turtle's image onto the graphics canvas.
Table 1

Procedures With a Variable Number of Inputs

A few operators now can accept a variable number of inputs. The most obvious example where this is needed is with the SENTENCE operator. Figure 2 shows how much cleaner this makes programs.

Figure 2

In order to supply an operator with a different number of inputs than it is declared to take, you simply surrount the operator name and the inputs with parenthesis. The operators which now can have a variable number of inputs are LIST, PRODUCT, SENTENCE, SUM, and WORD.

Bit Twiddling

Name	Input(s)	Description
ASHIFT	num1 num2	Outputs num1 arithmetic-shifted to the left by num2 bits. If num2 is negative, the shift is to the right with sign extension. The inputs must be integers.
BITAND	num1 num2	Outputs the bitwise AND of its inputs, which must be integers.
BITNOT	number	Outputs the bitwise NOT of its input, which must be an integer.
BITOR	num1 num2	Outputs the bitwise OR of its inputs, which must be integers.
BITXOR	num1 num2	Outputs the bitwise exclusive OR of its inputs, which must be integers.
LSHIFT	num1 num2	Outputs num1 shifted to the left by num2 bits. If num2 is negative, the shift is to the right with zero fill. The inputs must be integers.
Table 2

Audio Support

Name

Input(s)

Description

LOADCLIP

word
clipNumber

Reads in the .wav (waveform) audio file named word and associates it with clipNumber. This clip can then be played with the PLAYCLIP command. ClipNumber must be in the range 16 - 31.

LOADCLIP "meow.wav 16

PLAYCLIP

clipNumber

A WAV (waveform) audio clip is played.

Number	Audio Clip
1	Cat Meow
2	Computer Beeps
3	Dog Bark
4	Fairy Dust
5	Horse
6	Laser
7	Pop
8	Zoop

PLAYCLIP 2

PLAYNOTE

noteNumber
length

A MIDI note number is played for length seconds. In this scheme, middle C is note number 60 with all other notes relative to this.


                           Note Numbers
 Octave |  C  C#    D  D#    E    F  F#    G  G#    A  A#    B
 -------+--------+--------+----+--------+--------+--------+---
   -1   |  0   1 |  2   3 |  4 |  5   6 |  7   8 |  9  10 | 11
    0   | 12  13 | 14  15 | 16 | 17  18 | 19  20 | 21  22 | 23
    1   | 24  25 | 26  27 | 28 | 29  30 | 31  32 | 33  34 | 35
    2   | 36  37 | 38  39 | 40 | 41  42 | 43  44 | 45  46 | 47
    3   | 48  49 | 50  51 | 52 | 53  54 | 55  56 | 57  58 | 59
    4   | 60  61 | 62  63 | 64 | 65  66 | 67  68 | 69  70 | 71
    5   | 72  73 | 74  75 | 76 | 77  78 | 79  80 | 81  82 | 83
    6   | 84  85 | 86  87 | 88 | 89  90 | 91  92 | 93  94 | 95
    7   | 96  97 | 98  99 |100 |101 102 |103 104 |105 106 |107
    8   |108 109 |110 111 |112 |113 114 |115 116 |117 118 |119
    9   |120 121 |122 123 |124 |125 126 |127

The absolute octave number designations shown here are based on Middle C = C4.

PLAYNOTE 60 2

Turtle-to-Turtle Interaction

For a long time the TELL command has been available for one turtle to get another to perform a list of commands. Now a turtle can ASK another turtle to do something that results in an output to the ASKing turtle.

Name	Input(s)	Description
ASK	name [operation]	The turtle named name is passed an operation (an operator and its inputs if any) which it interprets and outputs the result to the asking turtle.

As an example, look at the operation:

     MAKE "otherPosition ASK "otherTurtle [POS]

This sets a variable named otherPosition to the location (the X and Y coordinates) of some other turtle.

Finally...

Lots, and I mean LOTS, of other procedures have been added. They are simply common commands and operations that exist in UCBLogo and I just had not gotten around to adding. You can checkout: