NAME
vgrindefs —
language definition data base for
vgrind(1)
SYNOPSIS
vgrindefs |
DESCRIPTION
The vgrindefs file contains all language
definitions for
vgrind(1). The data base is very similar to
termcap(5).
FIELDS
The following table names and describes each field.
| Name | Type | Description |
| ab | str | regular expression for the start of an alternate comment |
| ae | str | regular expression for the end of an alternate comment |
| pb | str | regular expression for start of a procedure |
| bb | str | regular expression for start of a lexical block |
| be | str | regular expression for the end of a lexical block |
| cb | str | regular expression for the start of a comment |
| ce | str | regular expression for the end of a comment |
| sb | str | regular expression for the start of a string |
| se | str | regular expression for the end of a string |
| lb | str | regular expression for the start of a character constant |
| le | str | regular expression for the end of a character constant |
| nc | str | regular expression for a non-comment (see below) |
| tl | bool | present means procedures are only defined at the top lexical level |
| oc | bool | present means upper and lower case are equivalent |
| kw | str | a list of keywords separated by spaces |
Non-comments are required to describe a certain context where a
sequence that would normally start a comment loses its special meaning. A
typical example for this can be found in Perl, where comments are normally
starting with ‘#’, while the string
‘$#’ is an operator on an array.
REGULAR EXPRESSIONS
Vgrindefs uses regular expression which
are very similar to those of
ex(1)
and lex(1). The characters `^', `$', `:' and `\' are reserved characters
and must be "quoted" with a preceding
‘\’ if they are to be included as
normal characters. The metasymbols and their meanings are:
- $
- the end of a line
- ^
- the beginning of a line
- \d
- a delimiter (space, tab, newline, start of line)
- \a
- matches any string of symbols (like .* in lex)
- \p
- matches any alphanumeric name. In a procedure definition (pb) the string that matches this symbol is used as the procedure name.
- ()
- grouping
- |
- alternation
- ?
- last item is optional
- \e
- preceding any string means that the string will not match an input string if the input string is preceded by an escape character (\). This is typically used for languages (like C) which can include the string delimiter in a string by escaping it.
Unlike other regular expressions in the system, these match words and not characters. Hence something like "(tramp|steamer)flies?" would match "tramp", "steamer", "trampflies", or "steamerflies".
KEYWORD LIST
The keyword list is just a list of keywords in the language separated by spaces. If the "oc" boolean is specified, indicating that upper and lower case are equivalent, then all the keywords should be specified in lower case.
FILES
- /usr/share/misc/vgrindefs
- File containing terminal descriptions.
EXAMPLES
The following entry, which describes the C language, is typical of a language entry.
C|c::pb=^\d?*?\d?\p\d?\(\a?\):bb={:be=}:cb=/*:ce=*/:sb=":se=\e":\
:lb=':le=\e':tl:\
:kw=asm auto break case char continue default do double else enum\
extern float for fortran goto if int long register return short\
sizeof static struct switch typedef union unsigned while #define\
#else #endif #if #ifdef #ifndef #include #undef # define else endif\
if ifdef ifndef include undef:
Note that the first field is just the language name (and any variants of it). Thus the C language could be specified to vgrind(1) as "c" or "C".
Entries may continue onto multiple lines by giving a \ as the last
character of a line. Capabilities in vgrindefs are
of two types: Boolean capabilities which indicate that the language has some
particular feature and string capabilities which give a regular expression
or keyword list.
SEE ALSO
HISTORY
The vgrindefs file format appeared in
4.2BSD.