Logo Applet



Use

The syntax of this language is pretty simple, it consists of a string of tokens, both commands and arguments, seperated by whitespace. Multiple ommands are executed from right to left. Each command is followed by zero or more arguments determined by the command (java bytecode style). Block structures are created with square brackets, "[" and "]". Everything within these brackets is treated as one command.

Arguments may be decimal numbers, variables, or arithmatic expressions using the four basic opperations, powers (a^b = a^b) and modulo (a%b = a modulo b). Orders of operation are supported but not parentheses, and no spaces. All arguments are given in pixels for distance and degrees for angles.

There are 8 primative commands which are used as follows.

penup
pendown
forward distance
back distance
left angle
right angle
clear
reset


User-defined commands can also be defined in the large text box. The format is as follows:

on commandName [arg1 [arg2 [...]]]
statement1
statement2
...
statementn
end

The difference between newlines and spaces is immaterial. Statements are commands and/or control structures. The control structors are as follows:

if expression1 compareType expression2 statement (CompareType is equals, greater than, less than, etc. Performs statement if the comparison is true)
repeat expression statement
make varName expression (Declare a variable and initalize it with a value. Also used to put a new value into a variable.)
stop (returns from a command invocation)



The source:
LogoApplet.java
LogoCanvas.java

And, optionally, LogoCanvasWithCNC.java which outputs standard CNC code to System.out.