Starts tokenizing the buffer for coloring and parenthesis matching.
The token-sym->style argument will be passed the first return
symbol from get-token, and it should return the style-name that
the token should be colored.
The get-token argument takes an input port and optionally an
offset and mode value. When it accepts just an input port,
get-token returns the next token as 5 values:
An unused value. This value is intended to represent the textual
component of the token and may be used as such in the future.
A symbol describing the type of the token. This symbol is
transformed into a style-name via the token-sym->style argument.
The symbols 'white-space and 'comment have special
meaning and should always be returned for white space and comment tokens
respectively. The symbol 'no-color can be used to indicate that
although the token is not white space, it should not be colored. The
symbol 'eof must be used to indicate when all the tokens have
been consumed.
A symbol indicating how the token should be treated by the paren
matcher or #f. This symbol should be in the pairs argument.
The starting position of the token (or #f if eof).
The ending position of the token (or #f if eof).
When get-token accepts an offset and mode value in addition to an
input port, it must also return two extra results, which are a backup
distance and new mode. The offset given to get-token can be added
to the position of the input port to obtain absolute coordinates within a
text stream. The mode argument allows get-token to communicate
information from earlier parsing to later. When get-token is
called for the beginning on a stream, the mode argument is #f;
thereafter, the mode returned for the previous token is provided to
get-token for the next token. The mode should not be a mutable
value; if part of the stream is re-tokenized, the mode saved from the
immediately preceding token is given again to the get-token
function. The backup distance returned by get-token indicates the
maximum number of characters to back up (counting from the start of the
token) and for re-parsing after a change to the editor within the token’s
region.
The get-token function is usually be implemented with a lexer using the
parser-tools/lex library. The
get-token function must obey the following invariants:
Every position in the buffer must be accounted for in exactly one
token, and every token must have a non-zero width.
The token returned by get-token must rely only on the
contents of the input port argument plus the mode argument. This
constraint means that the tokenization of some part of the input cannot
depend on earlier parts of the input except through the mode (and
implicitly through the starting positions for tokens).
A change to the stream must not change the tokenization of the
stream prior to the token immediately preceding the change plus the
backup distance. In the following example, this invariant does not hold
for a zero backup distance: If the buffer contains
and the tokenizer treats the unmatched " as its own token (a string error
token), and separately tokenizes the 1 2 and 3, an edit to make the
buffer look like
would result in a single string token modifying previous tokens. To
handle these situations, get-token can treat the first line as a
single token, or it can precisely track backup distances.
The pairs argument is a list of different kinds of matching
parens. The second value returned by get-token is compared to
this list to see how the paren matcher should treat the token. An example:
Suppose pairs is '((|(| |)|) (|[| |]|) (begin end)). This means
that there are three kinds of parens. Any token which has 'begin
as its second return value will act as an open for matching tokens with
'end. Similarly any token with '|]| will act as a
closing match for tokens with '|[|. When trying to correct a
mismatched closing parenthesis, each closing symbol in pairs will be
converted to a string and tried as a closing parenthesis.
Stops coloring and paren matching the buffer.
If clear-colors is true all the text in the buffer will have its
style set to Standard.
Causes the entire tokenizing/coloring system to become inactive.
Intended for debugging purposes only.
stop? determines whether the system is being forced to stop or
allowed to wake back up.
Indicates if the colorer for this editor has been stopped, or not.
Keep the text tokenized and paren matched, but stop altering the colors.
freeze-colorer will not return until the coloring/tokenization of
the entire text is brought up-to-date. It must not be called on a locked
text.
Start coloring a frozen buffer again.
If recolor? is #t, the text is re-colored. If it is
#f the text is not recolored. When recolor? is
#t, retokenize? controls how the text is recolored.
#f causes the text to be entirely re-colored before thaw-colorer
returns using the existing tokenization. #t causes the entire
text to be retokenized and recolored from scratch. This will happen in the
background after the call to thaw-colorer returns.
Set the region of the text that is tokenized.
Sets the currently active regions to be regions.
This returns the list of regions that are currently being colored in the
editor.
Returns the next non-whitespace character.
Starts from position and skips whitespace in the direction indicated by
direction. If comments? is true, comments are skipped as well as
whitespace. skip-whitespace determines whitespaces and comments by
comparing the token type to 'white-space and 'comment.
Must only be called while the tokenizer is started.
Skip all consecutive whitespaces and comments (using
skip-whitespace) immediately preceding the position. If the token
at this position is a close, return the position of the matching open, or
#f if there is none. If the token was an open, return
#f. For any other token, return the start of that token.
Must only be called while the tokenizer is started.
Return the starting position of the interior of the (non-atomic)
s-expression containing position, or #f is there is none.
Must only be called while the tokenizer is started.
Skip all consecutive whitespaces and comments (using
skip-whitespace) immediately following position. If the token at
this position is an open, return the position of the matching close, or
#f if there is none. For any other token, return the end of that
token.
Must only be called while the tokenizer is started.
The position is the place to put the parenthesis, and
char is the parenthesis to be added (e.g., that the user typed).
If fixup? is true, the right kind of closing parenthesis will be
chosen from the set previously passed to start-colorer—but only
if an inserted char would be colored as a parenthesis (i.e., with
the 'parenthesis classification). Otherwise, char will
be inserted, even if it is not the right kind. If flash? is true,
the matching open parenthesis will be flashed.
Return a symbol for the lexer-determined token type for the token that
contains the item after position.
Must only be called while the tokenizer is started.
Returns the range of the token surrounding position, if there is a
token there.
This method must be called only when the tokenizer is started.
Augments <method not found>.
This method is an observer for when the lexer is working. It is called
when the lexer’s state changes from valid to invalid (and back). The
valid? argument indicates if the lexer has finished running over
the editor (or not).
The default method just returns (void?).
Indicates if the lexer is currently valid for this editor.