MSTA(1) User Manuals MSTA(1)NAMEmsta - syntax description translator
SYNOPSISmsta [ -d-define-l-line -t -trace -v -verbose -b file_prefix -p
sym_prefix -h -help --help -w -c++ -enum -no-enum -pattern-equiv-no-
pattern-equiv -look-ahead number -la number -lr -no-lr -lalr-optimiza‐
tion -no-lalr-optimization -regular-optimization -no-regular-optimiza‐
tion -split-lr-sets-no-split-lr-sets-yacc-error-recovery-local-
error-recovery -minimal-error-recovery-error-reduce-no-error-reduce
-error-conflict -no-error-conflict -yacc-input -no-yacc-input -strict
-no-strict -yacc-file-names -no-yacc-file-names -o name -y -yacc -full-
lr-set -lr-situation-context -removed-lr-sets -expand -no-expand -time]
specification-file
DESCRIPTION
MSTA reads input grammar which is described in specification file and
generates parser for it. MSTA can process any POSIX YACC grammar and
generates equivalent parser in the sence of POSIX standard. But MSTA
can do many additional things: generation of more safe error recovery
or much better error recovery, better output of generated parser
description, generation of fast LALR(k)- and LR(k)-grammar parser with
acceptable space requirements, generation of scanners described as con‐
text-free grammar (CFG), and so on. The specification file must have
suffix `.y'
The generated code consists of optional interface and implementation
files and optional description file having the same names as one of
specification file and correspondingly suffixes `.h' (if option -d or
-c++ is given) and `.c' (C code) or `.cpp' (C++ code) and `.output'
(description file). If MSTA runs in YACC regime, the corresponding
files will be `y.tab.h' (if option -d or -c++ is given) and `y.tab.c'
(C code) or `y.tab.cpp' (C++ code) and `y.output' (description file).
Full documentation of MSTA is in MSTA User's manual.
OPTIONS
The options which are known for MSTA and YACC are:
-d Create the interface file. By default the interface file is not
generated.
-l Insert user's original code into generated parser without
`#line' constructs. By default constructions `#line' are always
generated.
-t Permit compilation of debugging code in the code file (tracing
of the parser work). Runtime debugging statements are always
contained in the parser, but by default conditional compilation
directives prevent their compilation. This option defines macro
`YYDEBUG' as 1 (by default its value is 0) and as consequence
the debugging statements are processed.
-v Create a file containing description of the parser.
-b file_prefix
Use file_prefix instead of `y' as the prefix for all output
filenames when YACC regime of generated file names is on.
-p sym_prefix
Use sym_prefix instead of yy as the prefix for all external
names (i.e. functions yyparse , yylex , and yyerror , and the
variables yylval , yychar , and yydebug ) produced by MSTA.
Additional options which are known only for MSTA are:
-define
This is synonym of option `-d'
-line This is synonym of option `-l'
-trace This is synonym of option `-t'
-verbose
This is synonym of option `-v'
-h, -help, --help
These options result in that only brief description of options
is output into stderr. The same result can be achieved by call‐
ing MSTA without any options and arguments.
-w No any warning messages are generated, e.g. repeated description
of type, value, and priority of token or terminal, repeated con‐
struction `%start' and many others.
-c++ Output of C++ code instead of C code (which is default).
-enum Generate token constants as enumeration instead of macro.
-no-enum
Generate token constants as macro (this is default).
-pattern-equiv
Equivalent patterns are denoted by the same nonterminal (by
default). Sometimes this results in dramatic reducing conflicts
when complex patterns are used.
-no-pattern-equiv
Even equivalent patterns are denoted by different nonterminals
and are expanded into the different set of rules
-look-ahead number, -la number
Determine maximal length of look-ahead when LR(k) and LALR(k)
generated parser. This does not mean that MSTA in each situa‐
tion and for each input will look ahead on given number tokens.
MSTA looks ahead only on minimal number of tokens required for
resolution of a conflict. The default value of maximal look
ahead is 1.
-lr Input grammar is considered to be a LR(k)-grammar.
-no-lr Input grammar is considered to be a LALR(k)-grammar. This is
default.
-lalr-optimization
If the input grammar is considered to be a LR(k)-grammar, MSTA
will make LALR(k)-optimization after building LR(k)-parser. It
means that MSTA will extract LALR(k)-parts of LR(k)-grammar and
will represent them by addequate LALR-sets. If the input
LR(k)-grammar is "almost" a LALR(k)-grammar, MSTA can descrease
size of the generated parser in several times. If the input
grammar is a LALR(k)-grammar, MSTA will create LALR(k)-parser.
This option is default when option `-lr' is given.
-no-lalr-optimization
When option `-lr' is given, MSTA does not make LALR-optimiza‐
tion.
-regular-optimization
After building LALR-sets or LR-sets and optional LALR-optimiza‐
tion, MSTA makes extracting regular parts of input grammar and
implement them by adequate methods (deterministic finite automa‐
ton). This decreases number of final states in the generated
parser, speeds up the parser, but sigthly increases the parser
size because some actions will be present in several examplars
in the parser. The more regular parts in the input grammar, the
better this method works. By default this option is on.
-no-regular-optimization
Disable the regular optimizations.
-split-lr-sets
Splitting LR-sets during regular optimization in order to
extract the most of regular parts (only when option `-regular-
optimization' is on). By default this option is on if
`%free_format' is present in the specification file.
-no-split-lr-sets
Option is opposite to the previous one. By default this option
is on if `%free_format' is absent in the specification file.
-yacc-error-recovery
The generated parser will use error recover according to Posix
YACC standard. This error recovery is used by default.
-local-error-recovery
The generated parser will use sligthly modified error recovery
method. This method is more safe. It is guaranteed that this
method can not be cycled.
-minimal-error-recovery
The generated parser will use a minimal cost error recovery
where the cost is overall number of tokens ignored. It is guar‐
anteed that this method can not be cycled. This method is
expensive because it may save many input tokens, parser states
and attributes.
-error-reduce
MSTA generates parser with possible default reducing (without
checking the look ahead) when the token error is in the context.
It means the parser may make a few reduces before recognizing a
syntax error. This option is default.
-no-error-reduce
The option means that the generated parser makes reduces in sit‐
uation where shift on error is possible only when there is cor‐
responding look ahead. It results in better error recovery but
the parser will have bigger size.
-error-conflict
MSTA reports conflicts on look ahead containing token error in
LR-set which is a result of shifting token error. This option
is default.
-no-error-conflict
Token error is not a real token it is never read but many error
recovery rules may generate conflicts on error. To avoid this
you can use the option. In this case MSTA does report conflicts
on look ahead containing token error in LR-set which is a result
of shifting token error.
-yacc-input
Only Posix YACC input can be used as input grammar.
-no-yacc-input
All input grammar features of MSTA can be used. This option is
default.
-yacc-file-names
MSTA output file names are generated according to Posix YACC (
y.output , y.tab.c , y.tab.h).
-strict
Use only strict POSIX YACC input (this option is in action only
when -yacc-input ) not SYSTEM V one. Errors are output when
nonstrict features are used. These features are usage of ';'
after definitions and C/C++ code insertions and usage of a token
and a literal in %type clauses as before and after a description
of the token and the literal. This option is on by default.
-no-strict
This option is in action only when -yacc-input is on. Only
warnings about non strict POSIX YACC features usage are output.
-no-yacc-file-names
Output files will have the same name and suffixes ( .h , .c ,
and .output ). This option is on by default.
-o Specify names of output files (header file name.h , code file
name.c , description file name.output
-y, -yacc
Emulate Posix YACC. It means that the options `-yacc-input' ,
`-lalr' , `-yacc-error-recovery' , and `-yacc-file-names' are
on, and -c++ is off. This option is useful with other options,
e.g. options `-lr' and `-y' means also `-yacc-input' , `-yacc-
error-recovery' , and `-yacc-file-names'.
-full-lr-set
Write all LR-situations (besides essential ones) of LR-sets into
a file containing description of the parser (the option acts
only with option `-v' ). Sometimes it is useful for better
understanding conflicts. But in this case the description file
can be significantly bigger.
-lr-situation-context
Write context of LR-situations into description of the parser
(the option acts only with option `-v' ). Sometimes it is use‐
ful for better understanding conflicts. But in this case the
description file can be huge espicially for LR(k)- and
LALR(k)-grammar when k > 1 or when with option `-full-lr-set'
parser generation speed because classic method of LR-, LALR-sets
is used instead of fast DeRemer method. By default this option
is off.
-removed-lr-sets
Write LR-sets removed during conflict resolution and regular
optimization into description of the parser (the option acts
only with option -v ). By default such unchievable LR-sets are
not present in the description file.
-expand
Attributes and states stacks in the parser will be expandable
(this is default).
-no-expand
Attributes and states stacks in the parser will be not expand‐
able.
-time Output detail time statistics of MSTA work on its basic passes
and optimizations.
FILES
file.y
MSTA specification file
file.c or y.tab.c
generated C implementation file
file.cpp or y.tab.cpp
generated C++ implementation file
file.h or y.tab.h
generated interface file
file.output or y.output
generated interface file
There are no any temporary files used by MSTA.
ENVIRONMENT
There are no environment variables which affect MSTA behavior.
DIAGNOSTICS
MSTA diagnostics is self-explanatory.
AUTHOR
Vladimir N. Makarov, vmakarov@users.sourceforge.net
SEE ALSOoka(1), sprut(1), nona(1), shilka(1). SHILKA manual.
BUGS
Please, report bugs to cocom-bugs@lists.sourceforge.net.
COCOM 5 SEP 1999 MSTA(1)
