The SPAN_REGEXP
rule is similar to the
SPAN
rule except the start sequence is taken to be
a regular expression. In addition to the attributes supported by
the SPAN
tag, the following attributes are supported:
HASH_CHAR
- a literal string which must be at the start of a regular expression.
HASH_CHARS
- a list of possible literal characters, one of which must match at the start of the regular expression.
HASH_CHAR
and HASH_CHARS
attributes are both optional, but you may only specify one, not both. If
both are specified, HASH_CHARS
is ignored and an error
is shown. Whenever possible, use a
literal prefix to specify a SPAN_REGEXP
. If the
starting prefix is always the same, use HASH_CHAR
and provide as much prefix as possible. Only in rare cases would you omit
both attributes, such as the case where there is no other reliable way to get
the highlighting you need, for example, with comments in the Cobol
programming language.
The regular expression match cannot span more than one line.
Any text matched by groups in the BEGIN
regular
expression is substituted in the END
string. See
below for an example of where this is useful.
Regular expression syntax is described in Appendix E, Regular Expressions.
Here is a SPAN_REGEXP
rule that highlights
“read-ins” in shell scripts:
<SPAN_REGEXP HASH_CHAR="<" TYPE="LITERAL1" DELEGATE="LITERAL"> <BEGIN><![CDATA[<<[\p{Space}'"]*([\p{Alnum}_]+)[\p{Space}'"]*]]></BEGIN> <END>$1</END> </SPAN_REGEXP>
Here is a SPAN_REGEXP
rule that highlights constructs
placed between <#ftl
and >
,
as long as the <#ftl
is followed by a word break:
<SPAN_REGEXP TYPE="KEYWORD1" HASH_CHAR="<" DELEGATE="EXPRESSION"> <BEGIN><#ftl\b</BEGIN> <END>></END> </SPAN_REGEXP>