ANTLR

Since torgo uses ANTLR for language parsing, a grammar file is used to specify the structure of the code. While not completely documented, this grammar file can give an insight into how the language behaves.

• Logo Grammar

Logo Commands

Commands in Torgo are case sensitive! ###repeat Repeat is a command for repeating a block of code a specified number of times.

###fd | forward Fd is for forward; which tells the turtle to move a specified number of pixels forward.

###bk | backward Bk is for backward; which tells the turtle to move a specified number of pixel backward.

###rt | right Rt is for right; which tells the turtle to move a specified number of degrees (NOT radian) to the right.

###lt | left Lt is for left; which tells the turtle to move a specified number of degrees (NOT radian) to the left.

###cs | cls | clear | clearscreen Cs is for clear screen. Resets the graphics on the screen.

###pu | penup Pu is for pen up. This allows movement of the turtle without drawing on the screen.

###pd | pendown Pd is for pen down. Any movement the turtle makes after pd (until pu is called) will draw on the screen.

###ht | hideturtle Ht is for hide turtle. Makes it so that the turtle is now shown on the screen.

###st | showturtle St is for show turtle. Makes it so that you can see the turtle on the screen.

###home Home moves the turtle to the center of the drawing area and points the turtle facing straight up.

###setxy Moves the turtle to the specified X Y coordinates.

###make Set a variable value.

###localmake Set a variable value at a local level.

###if If blocks allow condition testing. If the condition is true, then the internal block is executed. Supported conditional testing are:

• '<'
• '>'
• '=='
• '='
• '<='
• '>='
• '!='
• '<>'

###stop Stop will allow a block of code to exit from a function.

###for Allow a for loop. For loops initialize a variable and will loop through the desired values. For loops can increment or decrement in value; this behavior is determined by the start/stop values. An optional step value can be specified as a thrid argument to the for command.

###pc | pencolor Set the pen color. This can be hex, r g b, or by name.

###cc | canvascolor Set the canvas color. This can be hex, r g b, or by name.

###pause Pause execution for a specified amount of time. Time is specified in milli-seconds.

###ds | drawstring Draws a specified string to the screen.

###fontsize Set the font-size for drawing strings.

###fontstyle Set the font-style for drawing strings (italic, bold, plain).

###fontname Set the font-name for drawing strings.

###print Print a value to the console.