Author: David L. Dight (1987-1993)
NED has regular expression search and replace.
Versions:
- NED v1.7a from garbo.uwasi.fi
From the NED v1.7a User's Guide (nedit17a.zip:NED.DOC):
NED v1.7a User's Guide
Section 5.6 Regular Expression Reference
Introduction
This section describes the Regular Expression Language
used with the SPECIFY command. See section 5.1 for more
details on this command. Regular expressions are a way of
representing text patterns in a symbolic shorthand. The
symbols used to define these expressions fall into five
categories:
Symbols that match a specific character
Symbols that match any character
Symbols that match a character's position on the line
Symbols that match any of a set of characters or anything
except a set of characters
Symbols that let you match the previous symbol any number
of times
An expression may be made up of any or all of the above
categories.
CARAT (^) Start line
This symbol matches any text at the beginning of a line.
For example:
^cat
will match the string "cat" only if it is located at the
beginning of a line so that:
the cat
would not be matched.
DOLLAR ($) End line
This symbol matches any text at the end of a line. For
example:
cat$
will match the string "cat" only if it is located at the
end of a line so that:
cat nap
would not be matched.
PERIOD (.) Any character
This symbol matches any one character. Generally this
symbol by itself will always find a match. Its use is
usually as a placeholder. For example:
c.t
will match:
cat, cot, cut
but will not match:
coot, coat or couch etc.
ASTERISK (*) Match last expression
This symbol matches zero or more matches of the preceding
expression. For example:
c.*t
will match:
cat, coat, chart, compliment
Here the preceding expression is the period. Therefore
NED searches for any word starting with 'c' and ending in
't'.
SQUARE BRACKETS ([]) Character class
The square brackets define a set of characters known as a
character class. NED will then match any character in
that set. Character classes are usually used in
conjunction with other language elements. For example:
c[aou]t
will match:
cat, cot, cut
but will not match:
cet, cit, cyt
If the first character in the brackets is a carat (^)
then patterns with characters not appearing in the
brackets will be searched for. For example:
c[^aou]t
will not match:
cat, cot, cut
but will match:
cit, cet, cft, czt
The brackets may also be used to specify ASCII ordered
ranges by specifying the beginning and end of the range.
For example:
c[a-z][A-Z]t
matches any upper or lower case letter so that:
cat,cIt,crt,cGt
will all be matched.
SPECIAL CHARACTERS
The regular expression language allows you to search for
the following special characters:
\t tab
\s space
\b backspace
The backslash tells NED that the character that follows
is to be treated literally except with the above three
characters. Therefore to search for characters used in
the language, prefix them with the backslash as follows:
\\ backslash
\* asterisk
\. period
\^ carat
\[ left bracket
\] right bracket
\$ dollar
for example:
if\snot\s\[\*2\]
will match:
if not [*2]
EXAMPLES
You can form many expressions using the language. Here
are a few examples:
[a-z][a-z]*ism
Matches any 'ism' word e.g. 'prism'. In this example you
must repeat the character class range twice to match it
any number of times.
/\*.*\*/
Matches any comment line in a C program, for example: /*
this is a comment */
will be matched.
^[\s\t]*REM.*$
Matches any comment line in a BASIC program.
The following expression:
^[a-z][a-z]*[\s\t]*.*([^;]*)[^;]*$
will find any C function declaration with function body.
The expression searches for beginning of a line (^)
followed by one or more occurrences of any character in
the range a to z ([a-z][a-z]*) followed by either a space
or a tab repeated zero or more times ([\s\t]*), followed
by any character repeated zero or more times (.*),
followed by an open parenthesis (() followed by any
character except a semi-colon repeated zero or more times
([^;]*), followed by a close parenthesis ()), followed by
any character except a semi-colon repeated zero or more
times ([^;]*) followed by an end of line ($). For
example, the above expression would match:
WINDOW *get_window(int start,int finish,char *store)
but not match:
WINDOW *get_window (int, int, char *);
The above example only matches 'C' function bodies and
not function prototypes. It is useful for compiling a
cross-reference of all of the functions in a module. As
you can see expressions can be very complicated yet
extremely powerful filters can be created.