Used for commands, methods, functions, programs, and options. All terms shown in italic are typed literally. Italic is also used for filenames and URLs, and to highlight terms under discussion.

Used for code in program listings and for data structures and values to be entered exactly as shown. Also used for special variables, global variables, options showing resource and class names, and subwidget names.

Used to show arguments, options, and variables that should be replaced with user-supplied values.

Surround optional elements in a description of syntax. Note that square braces are also a commonly used Tcl language construct and appear in some Tcl program examples, in which case they are part of the Tcl code.

Used in syntax descriptions to separate items for which only one alternative may be chosen at a time.

Indicates that the preceding item may be repeated as many times as desired.