Preferences

The PREFS object contains a list of system-wide properties that control the look and feel of Logo. If you SAVE your workspace, the current settings are stored in the saved file. If you load a workspace that has been saved before, the settings are restored.

ARRAYBASE

Part of: PREFS

Controls the lowest array or grid index.

Syntax

GPROP "PREFS "ARRAYBASE
PPROP "PREFS "ARRAYBASE number

Description

The ARRAYBASE property controls the lowest value that you can use as an array or grid index. You may want to set the value to 1 if you prefer to index arrays and grids with a starting value of 1; actually, any starting value is legal as long as you are comfortable with that value.

Examples

GPROP “PREFS “ARRAYBASE Result: 0

AUTOSAVE

Part of: PREFS

Controls the amount of data that Logo saves and restores automatically.

Syntax

GPROP "PREFS "AUTOSAVE
PPROP "PREFS "AUTOSAVE modeF

Description

Logo can be configured to save your workspace, your turtles and everything else in frequent intervals. The AUTOSAVE property can be set to one of four values to tell Logo what to save:

Mode	Description
OFF	Nothing will be saved.
WORKSPACE	Logo saves all procedures, names and property lists. This is the default.
TURTLES	As with `WORKSPACE`, plus all turtles and the contents of the Graphics panel.
ALL	As with `TURTLES`, plus the Listener, all controls and bitmaps, and all global built-in names.

In the Web version, you can also set the AUTOSAVE property with an addition of an “autosave” argument to the link, as in this example:

https://weblogo.terrapinlogo.com?autosave=ALL

This is especially handy for classroom computers where you have a link for students to click.

Examples

GPROP “PREFS “AUTOSAVE Result: OFF

CASE

Part of: PREFS

Makes Logo convert its input to upper case or not.

Syntax

GPROP "PREFS "CASE
PPROP "PREFS "CASE TRUE/FALSE

Description

The CASE property causes Logo to convert all input to upper case if set to TRUE, except for words that are enclosed in vertical bars or back quotes. If CASE is FALSE, Logo does not convert any input to upper case. When Logo starts, it sets CASE to TRUE. Instead of setting the property CASE, you can also set the the global :CASE variable.

Important: If you set CASE to FALSE, all commands must be entered in UPPER CASE! Also, the case of all names and properties must remain in UPPER CASE!

Examples

GPROP “PREFS “CASE Result: TRUE

COLORED.TURTLES

Part of: PREFS

Displays turtles with their pen color.

Syntax

GPROP "PREFS "COLORED.TURTLES
PPROP "PREFS "COLORED.TURTLES TRUE/FALSE

Description

Setting the COLORED.TURTLES property to TRUE causes turtles to draw themselves using the current pen color if it is anything else but black.

Examples

GPROP “PREFS “COLORED.TURTLES Result: TRUE

CONTROLS.FONT

Part of: PREFS

Controls the font used when creating a control.

Syntax

GPROP "PREFS "CONTROLS.FONT
PPROP "PREFS "CONTROLS.FONT font

Description

The CONTROLS.FONT property gets or sets the font that Logo uses when creating a control. Set this property before creating a control so Logo can pick it up. For the font format, please see the SETFONT command.

Examples

GPROP “PREFS “CONTROLS.FONT Result: [HELVETICA 12 0]

DEBUGGER

Part of: PREFS

Controls the use of the Logo debugger.

Syntax

GPROP "PREFS "DEBUGGER
PPROP "PREFS "DEBUGGER TRUE/FALSE

Description

The DEBUGGER property controls whether the Logo debugger should be activated in case of a runtime error. If this property is set to TRUE (which is the default), the debugger activates so you can debug the problem. If set to FALSE, Logo prints the runtime error and returns to toplevel.

If the debugger is disabled, the Pause buttons are not visible

Examples

PPROP “PREFS “DEBUGGER FALSE

FONT

Part of: PREFS

Controls the Listener font.

Syntax

GPROP "PREFS "FONT
PPROP "PREFS "FONT font

Description

The FONT property gets or sets the font that the Listener panel uses for output. For the font format, please see the SETFONT command.

Examples

GPROP “PREFS “FONT Result: [MONOSPACE 12 0]

LISTENER.LINES

Part of: PREFS

Controls the maximum number of lines in the Listener panel.

Syntax

GPROP "PREFS "LISTENER.LINES
PPROP "PREFS "LISTENER.LINES number

Description

LISTENER.LINES controls the number of lines that the Listener panel’s output field will display. If Logo displays more than the given value, the oldest lines will be lost.

Examples

GPROP “PREFS “LISTENER.LINES Result: 1000

PICTURE.FORMAT

Part of: PREFS

Controls the file extension used for images if none was supplied.

Syntax

GPROP "PREFS "PICTURE.FORMAT
PPROP "PREFS "PICTURE.FORMAT format

Description

This is the default file extension for graphics images. Logo uses this extension if you access an image file without a specific extension.

Valid values are PNG, JPG, GIF, SVG, and BMP.

Examples

GPROP “PREFS “PICTURE.FORMAT Result: PNG

PRECISION

Part of: PREFS

Controls the number of decimals that Logo prints.

Syntax

GPROP "PREFS "PRECISION
PPROP "PREFS "PRECISION number

Description

PRECISION controls the number of decimal points that Logo outputs when printing a number. The value can be anything between 0 and 15; the value -1 instructs Logo to always print an appropriate number of decimals depending on the value.

Examples

GPROP “PREFS “PRECISION Result: 2 PI Result: 3.14 PPROP “PREFS “PRECISION 6 PI Result: 3.141593

PRINT.BITMAPS

Part of: PREFS

Controls the printing of bitmaps and turtles.

Syntax

GPROP "PREFS "PRINT.BITMAPS
PPROP "PREFS "PRINT.BITMAPS TRUE/FALSE

Description

PRINT.BITMAPS controls whether the saving or printing of the Graphics panel includes all visible bitmaps and turtles. If set to TRUE (which is the default), all visible bitmaps and turtles are saved or printed as well. Setting this property also changes the setting of the checkbox in the Save Picture and Print Picture dialogs.

Examples

GPROP “PREFS “PRINT.BITMAPS Result: TRUE

STACKSIZE

Part of: PREFS

Controls the maximum number of nested procedure calls.

Syntax

GPROP "PREFS "STACKSIZE
PPROP "PREFS "STACKSIZE size

Description

STACKSIZE controls the maximum number of nested procedure calls. If an executing Logo program calls more than this number of nested procedures, the program terminates with a runtime error.

Examples

GPROP “PREFS “STACKSIZE Result: 1000

TAB

Part of: PREFS

Controls the tab stop size used in the Listener’s output field.

Syntax

GPROP "PREFS "TAB
PPROP "PREFS "TAB tabs

Description

TAB controls the tab stop size used in the Listener’s output field. This is the approximate number of spaces that Logo would use when printing the Tab character (which is CHAR 9); see also the PRINT command for a list of special printing characters.

Examples

GPROP “PREFS “TAB Result: 4

TURTLE.FONT

Part of: PREFS

Controls the font used when creating a control.

Syntax

GPROP "PREFS "TURTLE.FONT
PPROP "PREFS "TURTLE.FONT font

Description

The TURTLE.FONT property gets or sets the font that turtles use when drawing text. For the font format, please see the SETFONT command.

Examples

GPROP “PREFS “TURTLE.FONT Result: [HELVETICA 12 0]

USERNAME

Part of: PREFS

Reports the user’s name.

Syntax

GPROP "PREFS "USERNAME

Description

This is the name that your Logo license is associated with.

Examples

GPROP “PREFS “USERNAME Result: Student User