Run LISP routines

What you will learn

What to expect when you load a LISP routine written for another CAD program: which parts run in CadCraft, and what it does not have yet.

CadCraft has its own LISP. It was written from the public AutoLISP reference, not from anyone else's program, so most routines written for AutoCAD run unchanged. Where something is missing, the command line names the function, so you can tell a gap in CadCraft from a mistake in the routine.

Type LISP on the command line

Type an expression that starts with ( and press ReturnEnter: (+ 1 2) prints 3. !name prints the value of a variable. An expression that doesn't close yet waits for the next line.

At a prompt, an expression answers it: at "Specify radius" type (* 2 12.5) for 25.

What runs

• The language: defun (with locals after /), setq, lambda, if, cond, while, repeat, foreach, progn, and, or, quote, apply, mapcar, eval, read, load, and *error* (a local *error* works). Names are not case-sensitive; integers and reals differ, as you expect ((/ 7 2) is 3).
• Built-in functions: maths, lists (car, cdr and their family, assoc, nth, member, subst, append…), strings (strcat, substr, strcase, wcmatch…), conversions (rtos, atof, itoa, angtos, distof, cvunit), geometry (polar, distance, angle, inters) and files (open, read-line, write-line, close, findfile).
• Commands: (defun c:NAME …) makes a command. (command …) and (command-s …) drive CadCraft's own commands, with pause for your answer.
• Prompts: getpoint, getcorner, getdist, getangle, getreal, getint, getstring, getkword with initget keywords, entsel, nentsel and ssget (W, C, F, WP, CP, P, L, X, with filter lists and -4 tests).
• Objects as lists: entget, entmod, entmake (blocks too), entdel, entlast, entnext (a block reference's attributes come after it as ATTRIBs, then a SEQEND, so attribute routines work), handent, selection sets, tblsearch and tblnext, layoutlist, regapp, getvar and setvar for the settings CadCraft has.
• Dialogs: .dcl files with load_dialog, new_dialog, action_tile, set_tile, get_tile, start_list, start_dialog, done_dialog. Buttons, edit boxes, list boxes, popup lists, toggles, radio buttons, rows, columns and boxes all show. A routine that writes its dialog to a temporary file works too.
• Objects: vl-load-com (it does nothing; nothing needs loading), the vl- list and string functions, vl-catch-all-apply, and vla-get-… / vla-put-… properties, vla-… methods and vlax-for over the Blocks, Layers and Layouts collections, model space and block definitions, with variants and safe arrays.

Routines tested

CadCraft's tests run a set of routines written for these checks (selection filters, prompts, commands, objects, error handlers), and one popular routine people asked for by name: Lee Mac's DelBlocks, by name through its dialog and by picking a block. CadCraft also has its own DELBLOCKS, so you don't need a routine for that.

Not built yet

• grread (tracking the mouse yourself), reactors (vlr-…), curve functions (vlax-curve-…), dictionaries and extended data (dictsearch, xdata in entget and entmake), and the Express Tools' acet-… functions.
• Images and slides in dialogs show as blank frames.
• Running another program, the Windows registry, and files outside the ones you load: a routine can write and read its own temporary files, which last until you close the page.

When a routine reaches one of these, the command line shows "no function definition" and the name, and says CadCraft does not have it yet.

Mistakes to avoid

• A command with the same name as one of CadCraft's. CadCraft's own command stays. Run the routine's as (c:NAME) on the command line.
• Running LISP you don't trust. A routine can change anything in the drawing, but nothing outside it: it can't reach your files, other sites or other apps.