Chapter 16 Input Editing and Completion Facilities

16.4 Reading and Writing Tokens

Sometimes after an accept method has read some input from the user, it may be necessary to insert a modified version of that input back into the input buffer. The following two functions can be used to modify the input buffer:

replace-input [Generic Function]

stream new-input&key start end buffer-start rescan
Replaces the part of the input editing stream stream's input buffer that extends from buffer-start to its scan pointer with the string new-input. buffer-start defaults to the current input position of stream. start and end can be supplied to specify a subsequence of new-input; start defaults to 0 and end defaults to the length of new-input.

replace-input queues a rescan by calling queue-rescan if the new input does not match the old output, or if rescan is t.

The returned value is the position in the input buffer.

presentation-replace-input [Generic Function]
stream object type view&key buffer-start rescan query-identifier for-context-type
Like replace-input, except that the new input to insert into the input buffer is obtained by presenting the object object with the presentation type type and view view. buffer-start and rescan are as for replace-input, query-identifier is as for accept, and for-context-type is as for present.

If the object does not have a readable representation (in the Lisp sense), presentation-replace-input may create an "accept result" to represent the object and insert it into the input buffer. For the purposes of input editing, "accept results" must be treated as a single input gesture.

The following two functions are used to read or write a token (that is, a string):

read-token [Function]

stream&key input-wait-handler pointer-button-press-handler click-only
Reads characters from the interactive steam stream until it encounters a delimiter, activation, or pointer gesture. Returns the accumulated string that was delimited by the delimiter or activation gesture, leaving the delimiter unread.

If the first character of typed input is a quotation mark (#\"), then read-token will ignore delimiter gestures until another quotation mark is seen. When the closing quotation mark is seen, read-token will proceed as discussed previously.

If the boolean click-only is t, then no keyboard input is allowed. In that case, read-token will simply ignore any typed characters.

input-wait-handler and pointer-button-press-handler are as for stream-read-gesture. Refer to Section 15.2.1, "The Extended Input Stream Protocol," for details.

write-token [Function]
token stream&key acceptably
write-token is the opposite of read-token; given the string token, it writes it to the interactive stream stream. If acceptably is t and there are any characters in the token that are delimiter gestures (see with-delimiter-gestures), then write-token will surround the token with quotation marks (#\").

Typically, present methods will use write-token instead of write-string.

CLIM 2.0 User's Guide - OCT 1998

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