6.3 Completion

For certain kinds of arguments, you can use completion to enter the argument value. Completion means that you type part of the argument, then SXEmacs visibly fills in the rest, or as much as can be determined from the part you have typed.

When completion is available, certain keys—TAB, RET, and SPC—are rebound to complete the text present in the minibuffer into a longer string that it stands for, by matching it against a set of completion alternatives provided by the command reading the argument. ? is defined to display a list of possible completions of what you have inserted.

For example, when M-x uses the minibuffer to read the name of a command, it provides a list of all available SXEmacs command names to complete against. The completion keys match the text in the minibuffer against all the command names, find any additional name characters implied by the ones already present in the minibuffer, and add those characters to the ones you have given. This is what makes it possible to type M-x inse SPC b RET instead of M-x insert-buffer RET (for example).

Case is normally significant in completion because it is significant in most of the names that you can complete (buffer names, file names and command names). Thus, ‘fo’ does not complete to ‘Foo’. When you are completing a name in which case does not matter, case may be ignored for completion’s sake if specified by program.

When a completion list is displayed, the completions will highlight as you move the mouse over them. Clicking the middle mouse button on any highlighted completion will “select” it just as if you had typed it in and hit RET.