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    Names: »kafka.6«

└─⟦b20c6495f⟧ Bits:30007238 EUUGD18: Wien-båndet, efterår 1987
    └─⟦this⟧ »EUUGD18/General/Insult/kafka.6« 

TextFile

.TH KAFKA 6
.SH NAME
kafka \- compile a language generator
.SH SYNOPSIS
.B kafka
[
.I file
] [
.B \-v
]
.SH DESCRIPTION
.I Kafka
compiles a BNF grammar into a language generator.
The
.B \-v
(verbose)
option sets a flag for the programmer's convenience.
.SH INPUT
.PP
.IR Kafka \&'s
source input looks like this:
.sp 0.5
.RS
.I declarations
.br
%%
.br
.I rules
.RE
.sp 0.5
The only legal contents of the ``declarations'' section
are sections of C source code to be compiled into the generator:
.sp 0.5
.RS
%{
.br
any legal C statements
.br
%}
.RE
.sp 0.5
A
.I rule
has the form
.sp 0.5
.RS
<\fInon-terminal\fR> \fB=\fR \fIsymbol\fR ... \fB{ \fIstatement;\fR ... \
\fBreturn\fR \fIexpression\fR \fB} ;\fR
.RE
.sp 0.5
A
.I symbol
may be a non-terminal enclosed in angle brackets
or a
.I terminal.
A terminal may be a string of non-blanks
or an arbitrary string surrounded by double quotes.
The optional series of statements in braces is executed
when the rule is tried.
If the last statement returns zero,
the generator rejects the rule and tries the next rule;
this is how the output is customarily randomized.
If the right-hand side of a rule contains no symbols,
the last statement is assumed to return a string pointer.
.SH USAGE
.PP
.I Kafka
writes the output grammar to the files
.I kaf.spec.c
and
.I kaf.text.c.
The interface to the grammar
normally consists of two standard routines,
.I maketext
and
.I kkoutput:
.RS
.sp
.ft B
int maketext(s)
.br
char *s;
.sp
int kkoutput(s)
.br
char *s;
.ft R
.RE
.sp
The argument of
.I maketext
is a non-terminal symbol.
The generator expands the symbol and stores the result
in an array.
.I Maketext
returns nonzero if something goes wrong.
.PP
The generator calls
.I kkoutput
with its output as argument.
.I Kkoutput
accumulates the output until called with the string ``@'' as argument.
It then punctuates, inserts
line breaks, and otherwise cleans up the accumulated text,
and dumps it to the standard output.
Imbedded
.B %n
becomes a newline,
.B %t
becomes a tab, and
.B %s
becomes a space.
A symbol beginning with
.B #
is concatenated to the preceding symbol.
.PP
The simplest possible main program is:
.RS
.sp
.ft B
.nf
.ta +4n
main() {
	maketext(``start'');
	kkoutput(``@'');
}
.ft R
.fi
.sp
.RE
.SH FILES
.ta \w'kaf.text.c   'u
kaf.spec.c	specifications for generator
.br
kaf.text.c	actions for generator
.SH "SEE ALSO"
insult(6)
.SH AUTHOR
Wayne Christopher