The ABC’s of AutoLISP

Introduction......Page 1 How This Book Is Organized......Page 2 Where to Find the LISP Programs......Page 3 Understanding the Interpreter and Evaluation......Page 5 The Components of an Expression......Page 6 Using Arguments and Expressions......Page 7 Understanding Data Types......Page 8 Integers and Real Numbers......Page 9 Object Names......Page 10 Assigning Values to Variables with Setq......Page 11 Preventing Evaluation of Arguments......Page 12 Applying Variables......Page 14 Assessing Single Elements of a List......Page 17 Functions for Assigning Values to Variables......Page 25 Adding Prompts......Page 26 What you Need......Page 29 Creating an AutoLISP File......Page 30 Running a Loaded Program......Page 31 Understanding How a Program Works......Page 33 Using AutoCAD Commands in AutoLISP......Page 36 How to Create a Program......Page 37 Local and Global Variables......Page 40 Automatic Loading of Programs......Page 42 Managing Large Acad.lsp files......Page 43 Using AutoLISP in a Menu......Page 44 Using Script Files......Page 46 Looking at a Programs Design......Page 48 Outlining Your Programming Project......Page 49 Using Functions......Page 50 Adding a Function......Page 53 Reusing Functions......Page 55 Creating an 3D Box program......Page 56 Creating a 3D Wedge Program......Page 61 Using Prettyprint......Page 64 Using Comments......Page 65 Dynamic Scoping......Page 67 CHAPTER 4: Interacting with the Drawing Editor......Page 70 Prompting the User for Distance......Page 71 A Sample Program Using Getdist......Page 74 Using Getangle and Getorient......Page 75 Using Getstring......Page 80 Using Getkword......Page 81 Using Initget......Page 82 Prompting for Dissimilar Variable Types......Page 84 How to Select Groups of Objects......Page 85 Using Ssget......Page 86 A Sample Program Using Ssget......Page 87 How to Test for Conditions......Page 91 Using the If function......Page 94 How to Make Several Expressions Act like One......Page 98 Using the Cond function......Page 100 How to Repeat parts of a Program......Page 103 Using the While Function......Page 104 Using the Repeat Function......Page 108 Using Test Expressions......Page 109 How to find Angles and Distances......Page 112 Understanding the Angle, Distance, and Polar Functions......Page 116 Using Trigonometry to Solve a Problem......Page 123 Gathering Information......Page 124 Finding Points Using Trigonometry......Page 128 Inters......Page 135 Cos......Page 136 Working With String Data Types......Page 138 Searching for Strings......Page 139 How to Convert Numbers to Strings and Back......Page 146 Converting a Number to a String......Page 147 Using a File Import Program......Page 152 Using a Text Export Program......Page 156 Reading the Cursor Dynamically......Page 162 Writing Text to the Status and Menu Areas......Page 167 Calling Menus from AutoLISP......Page 169 Drawing Temporary Images on the Drawing Area......Page 170 Adding Default Responses to your Program......Page 175 Dealing with Aborted Functions......Page 179 Using the *error* Function......Page 180 Organizing Code to Reduce Errors......Page 183 Common Programming Errors......Page 184 Using Variables as Debugging Tools......Page 185 CHAPTER 9: Using Lists to store data......Page 187 Using Simple Lists for Data Storage......Page 189 Evaluating Data from an Entire List at Once......Page 191 Using Complex Lists to Store Data......Page 192 Locating Elements in a List......Page 196 Searching Through Lists......Page 197 Using Selection Sets and Object Names......Page 201 Understanding the structure of Property Lists......Page 207 Getting an Object Name and Coordinate Together......Page 208 CHAPTER 10: Editing AutoCAD objects......Page 211 Editing Multiple objects......Page 212 Using Cmdecho to Speed up Your Program......Page 219 Improving Speed Through Direct Database Access......Page 220 Filtering a Selection Set......Page 226 Selecting Objects Based on Properties......Page 231 Accessing AutoCAD's System Tables......Page 233 Accessing Polyline Vertices......Page 237 Defining a New Polyline......Page 245 Drawing the new Polyline......Page 246 Testing for Polyline Types......Page 247 How Arcs are Described in Polylines......Page 248 Using Object Handles......Page 249 Using Object Handles......Page 254 Extracting Attribute Data......Page 256 Appendix A: Menu Primer......Page 259 Appendix B: Error Messages......Page 260 Appendix C: Group Codes......Page 261 Appendix D: System and Dimension Variables......Page 262