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- .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.
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