110 lines
3.2 KiB
Groff
110 lines
3.2 KiB
Groff
.TH TABGEN 1 "$Revision$"
|
|
.ad
|
|
.SH NAME
|
|
tabgen \- table generator for C-programs
|
|
.SH SYNOPSYS
|
|
.B tabgen
|
|
\fIarguments\fP
|
|
.SH DESCRIPTION
|
|
.I Tabgen
|
|
is a handy tool for generating tables for C-programs from a compact
|
|
description. The current version is only suitable for generating character
|
|
tables. The output is produced on standard output.
|
|
It works by maintaining an internal table of values, printing this table
|
|
when this is requested.
|
|
.PP
|
|
Each argument given to
|
|
.I tabgen
|
|
is either a command or a description. Descriptions are discussed first.
|
|
.PP
|
|
A description consists of a value (a string), directly followed by a semicolon,
|
|
directly followed by a list of indices for which the table to be generated
|
|
has this value. This list of indices must be in a certain \fBinputformat\fP,
|
|
characterized by a charactet.
|
|
Currently, there is only one inputformat, "c". In this format, the indices
|
|
are characters. There are two special characters: '\e' and '-'. The '\e'
|
|
behaves like in a C-string, and the '-' describes a range, unless
|
|
it starts the list of indices.
|
|
.PP
|
|
Some examples of descriptions:
|
|
.nf
|
|
STIDF:a-zA-Z_
|
|
STSKIP:\er \et\e013\ef
|
|
.fi
|
|
.PP
|
|
These descriptions have the effect that the internal table values for
|
|
'a' through 'z', 'A' through 'Z', and '_' are set to STIDF, and that the
|
|
internal table values for carriage-return, space, tab, vertical-tab, and
|
|
form-feed are set to STSKIP.
|
|
.PP
|
|
A command is introduced by a special character. On the command line,
|
|
a command is introduced by a '-'. The following commands are
|
|
recognized:
|
|
.IP I\fIchar\fP
|
|
switch to a different input format. This command is only there for future
|
|
extensions.
|
|
.IP f\fIfile\fP
|
|
read input from the file \fIfile\fP. In a file, each line is an argument
|
|
to \fItabgen\fP. Each line is either a command or a description. In a file,
|
|
commands are introduced by a '%'.
|
|
.IP F\fIformat\fP
|
|
Values are printed in a printf format. The default value for this format
|
|
is \fB"%s,\en"\fP. This can be changed with this command.
|
|
.IP T\fItext\fP
|
|
Print \fItext\fP literally at this point.
|
|
.IP p
|
|
Print the table as it is built at this point.
|
|
.IP C
|
|
Clear the table. This sets all internal table values to 0.
|
|
.IP i\fIstr\fP
|
|
Initialize all internal table values to \fIstr\fP. if \fIstr\fP is not
|
|
given, this command is equivalent to the C command.
|
|
.IP S\fInum\fP
|
|
Set the table size to \fInum\fP entries. The default size is 128.
|
|
.SH "AN EXAMPLE"
|
|
.PP
|
|
The next example is a part of the \fItabgen\fP description of the
|
|
character tables used by the lexical analyser of the ACK Modula-2 compiler.
|
|
This description resides in a file called char.tab.
|
|
.I
|
|
Tabgen
|
|
is called as follows:
|
|
.nf
|
|
tabgen -fchar.tab > char.c
|
|
.fi
|
|
.PP
|
|
The description as given here generates 2 tables: one indicating a class
|
|
according to which token a character can be a start of, and one indicating
|
|
whether a character may occur in an identifier.
|
|
.nf
|
|
|
|
% Comments are introduced with space or tab after the %
|
|
%S129
|
|
%F %s,
|
|
% CHARACTER CLASSES
|
|
%iSTGARB
|
|
STSKIP: \et\e013\e014\e015
|
|
STNL:\e012
|
|
STSIMP:-#&()*+,/;=[]^{|}~
|
|
STCOMP:.:<>
|
|
STIDF:a-zA-Z
|
|
STSTR:"'
|
|
STNUM:0-9
|
|
STEOI:\e200
|
|
%T#include "class.h"
|
|
% class.h contains #defines for STSKIP, STNL, ...
|
|
%Tchar tkclass[] = {
|
|
%p
|
|
%T};
|
|
% INIDF
|
|
%C
|
|
1:a-zA-Z0-9
|
|
%Tchar inidf[] = {
|
|
%F %s,
|
|
%p
|
|
%T};
|
|
.fi
|
|
.SH BUGS
|
|
.PP
|
|
.I Tabgen
|
|
assumes that characters are 8 bits wide.
|