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