LLGEN(1ACK)

NAME
LLgen, an extended LL(1) parser generator

SYNOPSIS
LLgen [ -vVxX ] file ...

DESCRIPTION
LLgen converts a context-free grammar into a set of functions which form a recursive descent parser with no backtrack. The grammar may be ambiguous; ambiguities can be broken by user specifications.

LLgen reads each file in sequence. Together, these files must constitute a context-free grammar. For each file, LLgen generates an output file, which must be compiled by the C-compiler. In addition, it generates the files Lpars.c and Lpars.h. Lpars.h contains the define statements that associate the LLgen-assigned `token-codes' with user declared `token-names'. This allows other source files, for instance the source file containing the lexical analyzer, to access the token-codes by using the token-names. Lpars.c contains the error recovery routines and tables. It must also be compiled by the C-compiler.

LLgen will only update those output files that differ from their previous version. This allows LLgen to be used with make (I) convieniently.

To obtain a working program, the user must also supply a lexical analyzer, as well as main and LLmessage, an error reporting routine; Lex (I) is a useful program for creating lexical analysers usable by LLgen.

If the -v or the -V flag is given, the file LL.output is prepared, which contains a description of the conflicts that were not resolved. If it is given more than once, LLgen will be more "verbose". If it is given three times, a complete description of the grammar will be supplied.

If the -x or the -X flag is given, the sets that are computed are extended with the nonterminal symbols and these extended sets are also included in the LL.output file.

If the -w or the -W flag is given, no warnings are given.

FILES
LL.output verbose output file
Lpars.c the error recovery routines
Lpars.h defines for token names

SEE ALSO
lex (I)
make (I)
LLgen, an Extended LL(1) Parser Generator by C.J.H. Jacobs.

DIAGNOSTICS
Are intended to be self-explanatory. They are reported on standard error. A more detailed report is found in the LL.output file.

BUGS
Because some file names are fixed, at most one LLgen process can be active in a given directory at a time.

AUTHOR
Ceriel J. H. Jacobs