Logo Lesson 2 Logo ProceduresLesson PrerequisitesLesson ObjectivesWhat is a Logo procedure?Slide 5Slide 6How do you create a procedure?Creating a Procedure using TOSlide 9Creating a Procedure using EDITSlide 11Slide 12Slide 13The Logo WorkspaceSlide 15Saving a Logo WorkspaceLoading a Logo WorkspaceSummary of Steps to Create a Logo ProcedureSlide 19Slide 20“Running” a Logo ProcedureProcedure Names as Logo CommandsSlide 23Self Check for Lesson 2Slide 25Slide 26Slide 27Slide 28Slide 29Slide 30Slide 31Slide 32Slide 33Slide 34Slide 35Try some Logo proceduresLogo Lesson 2Logo ProceduresTBE 540-40Fall 2004Farah FisherLesson PrerequisitesBefore beginning this lesson, the student must be able to…Start the Logo program (appropriate version)Create simple shapes using FD, BK, LT, RT, REPEATUse pen control commands such as PU, PD, PE, PPT (PP)Change pen color and background color using SETPC or SETBG or a menuLesson ObjectivesAfter completing this lesson, the student will be able to…Explain the concept of Logo proceduresCreate a new Logo procedureEdit an existing Logo procedureExecute (run) a Logo procedureSave and load workspacesList all procedures in a workspace using POTSWhat is a Logo procedure?When you used Logo in Lesson 1, each time you typed a command (or set of commands), the turtle moved immediately.However, the turtle did not “remember” how to make the shape. To create the shape again, you needed to type the commands again.A procedure is a way to make the turtle remember a set of commands.What is a Logo procedure?Each procedure is given a name (e.g., SQUARE or HOUSE or BIG.RED.THING). The name may not include spaces.Creating the procedure is like teaching the Logo turtle the meaning of a word. For example, we can teach the turtle that the word SQUARE means REPEAT 4 [FD 50 RT 90]Afterwards, every time we type the word SQAURE, the turtle will know what to do.What is a Logo procedure?Procedures are kept in memory as part of a Logo workspace. The workspace is a collection of all the Logo procedures currently in memory.These workspaces can be save and loaded, just like other documents.More information about workspaces will be presented later.How do you create a procedure?Various versions of Logo may ask that you begin procedures in different ways. This lesson will show two of the most common ways to start making a procedure. Check the manual or HELP function of your version of Logo for more information.Creating a Procedure using TOAll Logo procedures actually have the word TO as part of the name (e.g., TO SQUARE or TO HOUSE).All versions of Logo allow this method for creating procedures.To begin a procedure, type the word TO and a name for the procedure.For example, you could type TO MY.NAME or TO TRIANGLECreating a Procedure using TO You will see a symbol like this: >The symbol means “it is your turn to type something”.Type one or more Logo commands and press Return/Enter. Another > will appear.After you have finished all commands, type END at the > symbol.NOTE: You cannot immediately edit a previous line using this method. You must edit later.Creating a Procedure using EDITAll versions of Logo allow you to edit an existing procedure using the command EDIT.Some versions of Logo also allow EDIT to be used to create new procedures (check your HELP file or manual).To begin a new procedure or edit an old one, type the word EDIT, a quote and the procedure name. Example: EDIT “SQUARECreating a Procedure using EDITThere are several things to notice when using the EDIT command (e.g., EDIT “HOUSE.BOAT)There is a space after the word EDIT.There is no space between the quote and the name of the procedure.There is no quote after the procedure name. Many Logo commands follow this pattern.Creating a Procedure using EDITYou will probably see the following two lines in the editing window when you begin a new procedure:TO SQUARE (or whatever you specified as the name)ENDYou will be typing the commands between these two lines, so you may need to press Return/Enter to open up space to type.Creating a Procedure using EDITFinishing and saving a procedure using EDIT will depend on the version of Logo you are using.There may be a menu item such as “Save and Exit”.There may be a specific command on the keyboard.The simplest way is to attempt to close the editing window. The computer should ask if you want to save the changes.The Logo WorkspaceEarlier in this lesson, a workspace was defined as a collection of procedures in memory.Every time you create and save a procedure, it becomes part of the current workspace.NOTE: Saving a procedure does not put it on a disk. It exists only in memory until the entire workspace is saved.The Logo WorkspaceThe POTS command (Print Out Titles) shows you a list of all the procedures in memory.In the list, each procedure name will have the word TO in front of it. For example (the ? is the prompt in most Logo versions - no need to type it):? POTSTO SQUARETO TRIANGLETO HOUSESaving a Logo WorkspaceTo save a workspace on disk (including all procedures in memory), type SAVE “filenameThe filename may be anything that is appropriate for your operating system. In some versions of Logo, an extension of .LGO will be added to the end of the filename.There may be a menu item for SAVE in some versions of Logo.Loading a Logo WorkspaceTo load a workspace that has previously been saved to disk (including all procedures in memory), type LOAD “filename All procedures will come into memory. If some procedures are in memory before the LOAD, the new ones will simply be added to the POTS list.There may be a menu item for LOAD in some versions of Logo.Summary of Steps to Create a Logo ProcedureDecide what commands will be included in your Logo procedure and think of a name for it (with no spaces)In your Logo program, do one of the following:Type TO and the procedure name (TO SQ)Type EDIT “ and the procedure name (EDIT “SQ)Enter the commands in the procedure.Summary of Steps to Create a Logo ProcedureWhen you have finished the procedure, exit and save using one of these methods:If you began with TO, type END on the last line.If you began with EDIT, close the window and save (or use the appropriate menu choice or keys)Your procedure will become part of the POTS