java_cup
Class Main

java.lang.Object
  java_cup.Main

public class Main

extends java.lang.Object

This class serves as the main driver for the JavaCup system. It accepts user options and coordinates overall control flow. The main flow of control includes the following activities:

• Parse user supplied arguments and options.
• Open output files.
• Parse the specification from standard input.
• Check for unused terminals, non-terminals, and productions.
• Build the state machine, tables, etc.
• Output the generated code.
• Close output files.
• Print a summary if requested.

Options to the main program include:

-package name

specify package generated classes go in [default none]

-parser name

specify parser class name [default "parser"]

-symbols name

specify name for symbol constant class [default "sym"]

-interface

emit symbol constant interface, rather than class

-nonterms

put non terminals in symbol constant class

-expect #

number of conflicts expected/allowed [default 0]

-compact_red

compact tables by defaulting to most frequent reduce

-nowarn

don't warn about useless productions, etc.

-nosummary

don't print the usual summary of parse states, etc.

-progress

print messages to indicate progress of the system

-time

print time usage summary

-dump_grammar

produce a dump of the symbols and grammar

-dump_states

produce a dump of parse state machine

-dump_tables

produce a dump of the parse tables

-dump

produce a dump of all of the above

-debug

turn on debugging messages within JavaCup

-nopositions

don't generate the positions code

-noscanner

don't refer to java_cup.runtime.Scanner in the parser (for compatibility with old runtimes)

-version

print version information for JavaCUP and halt.

Field Summary

protected static parse_action_table	action_table Resulting parse action table.
protected static long	build_end Timing data -- when did we end state and table building
protected static long	check_end Timing data -- when did we end checking
protected static long	dump_end Timing data -- when did we end dumping
protected static long	emit_end Timing data -- when did we finish emitting code
protected static int	expect_conflicts User option -- number of conflicts to expect
protected static long	final_time Timing data -- when were we completely done
protected static long	first_end Timing data -- when did we end first set calculation
protected static boolean	include_non_terms User option -- should we include non terminal symbol numbers in the symbol constant class.
protected static java.io.BufferedInputStream	input_file Input file.
protected static boolean	lr_values User option -- should generator generate code for left/right values?
protected static long	machine_end Timing data -- when did we end state machine construction
protected static boolean	no_summary User option -- do not print a summary.
protected static long	nullability_end Timing data -- when did we end nullability calculation
protected static boolean	opt_compact_red User option -- do we compact tables by making most common reduce the default action
protected static boolean	opt_do_debug User option -- do we run produce extra debugging messages
protected static boolean	opt_dump_grammar User option -- do we produce a dump of the grammar
protected static boolean	opt_dump_states User option -- do we produce a dump of the state machine
protected static boolean	opt_dump_tables User option -- do we produce a dump of the parse tables
protected static boolean	opt_show_timing User option -- do we show timing information as a part of the summary
protected static long	parse_end Timing data -- when did we end parsing
protected static java.io.PrintWriter	parser_class_file Output file for the parser class.
protected static long	prelim_end Timing data -- when did we end preliminaries
protected static boolean	print_progress User option -- do we print progress messages.
protected static long	reduce_check_end Timing data -- when did we end checking for non-reduced productions
protected static parse_reduce_table	reduce_table Resulting reduce-goto table.
protected static lalr_state	start_state Start state in the overall state machine.
protected static long	start_time Timing data -- when did we start
protected static boolean	suppress_scanner User option -- should generator suppress references to java_cup.runtime.Scanner for compatibility with old runtimes?
protected static boolean	sym_interface User option -- should symbols be put in a class or an interface? [CSA]
protected static java.io.PrintWriter	symbol_class_file Output file for the symbol constant class.
protected static long	table_end Timing data -- when did we end table construction

Constructor Summary

private

Main() Only constructor is private, so we do not allocate any instances of this class.

Method Summary

protected static void	build_parser() Build the (internal) parser from the previously parsed specification.
protected static void	check_unused() Check for unused symbols.
protected static void	close_files() Close various files used by the system.
static void	dump_grammar() Produce a human readable dump of the grammar.
static void	dump_machine() Produce a (semi-) human readable dump of the complete viable prefix recognition state machine.
static void	dump_tables() Produce a (semi-) human readable dumps of the parse tables
protected static void	emit_parser() Call the emit routines necessary to write out the generated parser.
protected static void	emit_summary(boolean output_produced) Emit a long summary message to standard error (System.err) which summarizes what was found in the specification, how many states were produced, how many conflicts were found, etc.
static void	main(java.lang.String[] argv) The main driver for the system.
protected static void	open_files() Open various files used by the system.
protected static void	parse_args(java.lang.String[] argv) Parse command line options and arguments to set various user-option flags and variables.
protected static void	parse_grammar_spec() Parse the grammar specification from standard input.
protected static java.lang.String	plural(int val) Helper routine to optionally return a plural or non-plural ending.
protected static void	show_times() Produce the optional timing summary as part of an overall summary.
protected static java.lang.String	timestr(long time_val, long total_time) Helper routine to format a decimal based display of seconds and percentage of total time given counts of milliseconds.
protected static void	usage(java.lang.String message) Print a "usage message" that described possible command line options, then exit.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

print_progress

protected static boolean print_progress

User option -- do we print progress messages.

opt_dump_states

protected static boolean opt_dump_states

User option -- do we produce a dump of the state machine

opt_dump_tables

protected static boolean opt_dump_tables

User option -- do we produce a dump of the parse tables

opt_dump_grammar

protected static boolean opt_dump_grammar

User option -- do we produce a dump of the grammar

opt_show_timing

protected static boolean opt_show_timing

User option -- do we show timing information as a part of the summary

opt_do_debug

protected static boolean opt_do_debug

User option -- do we run produce extra debugging messages

opt_compact_red

protected static boolean opt_compact_red

User option -- do we compact tables by making most common reduce the default action

include_non_terms

protected static boolean include_non_terms

User option -- should we include non terminal symbol numbers in the symbol constant class.

no_summary

protected static boolean no_summary

User option -- do not print a summary.

expect_conflicts

protected static int expect_conflicts

User option -- number of conflicts to expect

lr_values

protected static boolean lr_values

User option -- should generator generate code for left/right values?

sym_interface

protected static boolean sym_interface

User option -- should symbols be put in a class or an interface? [CSA]

suppress_scanner

protected static boolean suppress_scanner

User option -- should generator suppress references to java_cup.runtime.Scanner for compatibility with old runtimes?

start_time

protected static long start_time

Timing data -- when did we start

prelim_end

protected static long prelim_end

Timing data -- when did we end preliminaries

parse_end

protected static long parse_end

Timing data -- when did we end parsing

check_end

protected static long check_end

Timing data -- when did we end checking

dump_end

protected static long dump_end

Timing data -- when did we end dumping

build_end

protected static long build_end

Timing data -- when did we end state and table building

nullability_end

protected static long nullability_end

Timing data -- when did we end nullability calculation

first_end

protected static long first_end

Timing data -- when did we end first set calculation

machine_end

protected static long machine_end

Timing data -- when did we end state machine construction

table_end

protected static long table_end

Timing data -- when did we end table construction

reduce_check_end

protected static long reduce_check_end

Timing data -- when did we end checking for non-reduced productions

emit_end

protected static long emit_end

Timing data -- when did we finish emitting code

final_time

protected static long final_time

Timing data -- when were we completely done

input_file

protected static java.io.BufferedInputStream input_file

Input file. This is a buffered version of System.in.

parser_class_file

protected static java.io.PrintWriter parser_class_file

Output file for the parser class.

symbol_class_file

protected static java.io.PrintWriter symbol_class_file

Output file for the symbol constant class.

start_state

protected static lalr_state start_state

Start state in the overall state machine.

action_table

protected static parse_action_table action_table

Resulting parse action table.

reduce_table

protected static parse_reduce_table reduce_table

Resulting reduce-goto table.

Constructor Detail

Main

private Main()

Only constructor is private, so we do not allocate any instances of this class.

Method Detail

main

public static void main(java.lang.String[] argv)
                 throws internal_error,
                        java.io.IOException,
                        java.lang.Exception

The main driver for the system.

Parameters:

argv - an array of strings containing command line arguments.

Throws:

internal_error

java.io.IOException

java.lang.Exception

usage

protected static void usage(java.lang.String message)

Print a "usage message" that described possible command line options, then exit.

Parameters:

message - a specific error message to preface the usage message by.

parse_args

protected static void parse_args(java.lang.String[] argv)

Parse command line options and arguments to set various user-option flags and variables.

Parameters:

argv - the command line arguments to be parsed.

open_files

protected static void open_files()

Open various files used by the system.

close_files

protected static void close_files()
                           throws java.io.IOException

Close various files used by the system.

Throws:

java.io.IOException

parse_grammar_spec

protected static void parse_grammar_spec()
                                  throws java.lang.Exception

Parse the grammar specification from standard input. This produces sets of terminal, non-terminals, and productions which can be accessed via static variables of the respective classes, as well as the setting of various variables (mostly in the emit class) for small user supplied items such as the code to scan with.

Throws:

java.lang.Exception

check_unused

protected static void check_unused()

Check for unused symbols. Unreduced productions get checked when tables are created.

build_parser

protected static void build_parser()
                            throws internal_error

Build the (internal) parser from the previously parsed specification. This includes:

• Computing nullability of non-terminals.
• Computing first sets of non-terminals and productions.
• Building the viable prefix recognizer machine.
• Filling in the (internal) parse tables.
• Checking for unreduced productions.

Throws:

internal_error

emit_parser

protected static void emit_parser()
                           throws internal_error

Call the emit routines necessary to write out the generated parser.

Throws:

internal_error

plural

protected static java.lang.String plural(int val)

Helper routine to optionally return a plural or non-plural ending.

Parameters:

val - the numerical value determining plurality.

emit_summary

protected static void emit_summary(boolean output_produced)

Emit a long summary message to standard error (System.err) which summarizes what was found in the specification, how many states were produced, how many conflicts were found, etc. A detailed timing summary is also produced if it was requested by the user.

Parameters:

output_produced - did the system get far enough to generate code.

show_times

protected static void show_times()

Produce the optional timing summary as part of an overall summary.

timestr

protected static java.lang.String timestr(long time_val,
                                          long total_time)

Helper routine to format a decimal based display of seconds and percentage of total time given counts of milliseconds. Note: this is broken for use with some instances of negative time (since we don't use any negative time here, we let if be for now).

Parameters:

time_val - the value being formatted (in ms).

total_time - total time percentages are calculated against (in ms).

dump_grammar

public static void dump_grammar()
                         throws internal_error

Produce a human readable dump of the grammar.

Throws:

internal_error

dump_machine

public static void dump_machine()

Produce a (semi-) human readable dump of the complete viable prefix recognition state machine.

dump_tables

public static void dump_tables()

Produce a (semi-) human readable dumps of the parse tables