Lingo in a Nutshell

Chapter 19. The Lingo Symbol Table

Director maintains a hidden table containing every keyword or “symbol” in use. In this context, symbol denotes any word Director recognizes, including “true” Lingo symbols that begin with a pound sign (#). (Refer to Chapter 18.) In point of fact, all recognized keywords are converted to symbols for storage in the Symbol Table. Thus, the keyword mouseUp is stored internally as #mouseUp. See "Symbols" in Chapter 5, for the party line regarding true Lingo symbols, which I will refer to as “Lingo symbols” in this chapter to indicate those items traditionally thought of as symbols.

The Symbol Table includes built-in symbols and keywords defined by Director itself, and symbols, variable names, handlers, and so on, defined by the programmer.

Tip

See the downloadable Chapter 22, Symbol Table Archaeology, at http://www.zeusprod.com/nutshell/chapters/symtable.html for many more details.

Why Do I Care?

You can use the Symbol Table for some neat stuff (which is what being a geek is all about).

• Verify whether Director recognizes a particular keyword. This is useful when there is a typographical error in the documentation. For example, the FileIO Xtra’s documentation claims that it supports a method called getOSdir, which is actually named getOSdirectory. You can verify that getOSdir is not recognized by Director and therefore not a valid keyword.

• Avoid overflowing the Symbol Table (applies only to Windows 3.1). If your movie suddenly starts behaving very oddly under ...