SCANL
Returns a pattern matching the longest string that does not contain any
of the characters the specified string, range, or buffer. A pattern
created with SCANL can match text containing line breaks.
SCANL fails if it finds no characters other than those present in its
argument. SCAN succeeds if it finds at least one character not
specified in the first parameter.
Syntax
pattern := SCANL ({string | range | buffer} [, {FORWARD | REVERSE}])
Parameters
string A string containing the characters that cause
VAXTPU to stop matching characters in the searched
text.
range A range containing the characters that cause
VAXTPU to stop matching characters in the searched
text.
buffer A buffer containing the characters that cause
VAXTPU to stop matching characters in the searched
text.
FORWARD A keyword directing VAXTPU to match characters in
the forward direction.
REVERSE A keyword directing VAXTPU to match characters as
follows: First, match characters in the forward
direction until VAXTPU finds a character that is a
member of the set of characters in the specified
buffer, range, or string. Next, return to the
first character that SCANL matched and start
matching characters and line breaks in the reverse
direction until VAXTPU finds a character in the
specified buffer, range, or string. You can
specify REVERSE only if you are using SCANL in the
first element of a pattern being used in a reverse
search. In other contexts, specifying REVERSE has
no effect.
The behavior enabled by REVERSE allows an
alternate form of reverse search. By default, a
reverse search stops as soon as a successful match
occurs, even if there might have been a longer
successful match in the reverse direction. By
specifying REVERSE with SCANL, you direct VAXTPU
not to stop matching in either direction until it
has matched as many characters as possible.
Examples
1. The following assignment statement creates a pattern that matches a
sentence. It assumes that a sentence ends in a period, exclamation
mark, or question mark. It also assumes that a sentence contains
at least two letters. The matched text does not include the
punctuation mark.
sentence_pattern := ANY ("ABCDEFGHIJKLMNOPQRSTUVWXYZ") + SCANL
(".!?");
2. pat1 := SCANL ('abc');
This assignment statement stores in "pat1" a pattern that matches
the longest string of characters that does not contain an a, b, or
c.
3. pat1 := SCANL ('abc', FORWARD);
This statement has exactly the same effect as Example 1.
4. word := SCANL (' ', REVERSE);
This statement defines the variable "word" to mean the longest
consecutive string of characters that does not include a space
character. If you use the following statement:
the_range := SEARCH (word, REVERSE);
when the cursor is on the "n" in Xanadu in the following text:
"In Xanadu did Kublai Khan a stately pleasure dome decree"
then the variable "the_range" contains the word "Xanadu". This is
because when you use SCANL with REVERSE as the first element of a
pattern, and then use that pattern in a reverse search, SCANL
matches as many characters as possible in both the forward and
reverse directions.
If the cursor is on "n" but you define the variable "word" without
the REVERSE keyword, like this:
word := SCANL (' ');
and then do a reverse search, "the_range" contains the characters
"nadu".
Related Topics
ANCHOR ANY ARB MATCH NOTANY SCAN
SEARCH SEARCH_QUIETLY SPAN SPANL UNANCHOR