Using the Apropos Feature

AutoCAD AutoLISP & Visual LISP

 
Using the Apropos Feature
 
 
 

The Apropos feature is a tool that searches the VLISP symbol table. The symbol table contains every symbol read by the AutoLISP reader. This includes symbols in user programs and symbols that implement the AutoLISP language.

You can define specific search criteria for Apropos to use in searching the symbol table. For example, you can tell Apropos to search for all symbol names that contain a specific character string, and you can further refine that search to return only symbols that identify functions.

To invoke Apropos, choose View Apropos Window from the VLISP menu, or press the Apropos button on the VLISP toolbar. If you select text prior to invoking Apropos, VLISP immediately performs an Apropos search on the selected text. If no text is selected, VLISP displays the Apropos Options dialog box.

In the input field of the Apropos Options dialog box, enter the text you want Apropos to search for. The dialog box contains the following options:

Match by Prefix

If this option is turned on, Apropos searches for a match starting only from the first character of the symbol name. If the option is turned off, Apropos tries to match the text you entered starting at any position of a symbol name.

For example, with Match by Prefix off, a search on the word get returns symbol names including getint, getpoint, ssget, and vla-getActive. With Match by Prefix on, the same search does not return ssget and vla-getActive, because get appears in the middle of those symbol names, not at the beginning.

Use WCMATCH (wild card match)

If this option is turned on, Apropos treats asterisks as wild-card characters when searching. For example, if you specify fun* as the symbol you want matched, Apropos looks for all names that contain fun, no matter what characters follow. In contrast, with Use WCMATCH turned off, the asterisk is treated as a string and Apropos only matches names that precisely contain fun*.

Downcase Symbols

If this option is turned on, any symbols you copy to the Clipboard with the Apropos service are converted to lowercase characters. If you paste the symbol name in another window, it appears in lowercase.

Filter Flags

This option lets you choose symbols with matching flag settings. VLISP displays a list of check boxes that correspond to the symbol flags described in Understanding Symbol Flags. If the flag filter is on, only symbols set with the selected flags are considered.

Filter Value

Opens the Filter Value dialog box, from which you can select additional search criteria. You can choose one of the following:

All No filter.

Null value Only nil-valued symbols are considered for matching.

Nonull value Only symbols that are not nil are considered for matching.

Functions All function types (user-defined, built-in, and so on) are considered for matching.

User function Only user-defined functions (USUBR) are considered.

Built-in function Only built-in or compiled AutoLISP functions (SUBR) are considered for matching.

Exrxsubr Only external function names are matched.

If you specify a filter value or filter flag, the message area of the Apropos options dialog box indicates your selections.

When you've specified the criteria you want Apropos to use in its search, press OK to conduct the search.

To search for AutoLISP symbols that begin with set

  1. Choose View Apropos Window from the VLISP menu.
  2. Enter set in the text input field of the Apropos options dialog box.
  3. Select the Match by Prefix option.
  4. Clear all other options in the Apropos options dialog box.
  5. Press OK to conduct the search.