Main (Java CUP Parser Generator 0.11-a-czt02-SNAPSHOT API)

java.lang.Object
- java_cup.Main

```
public class Main
extends 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.
Version:

last updated: 7/3/96

Author:

Frank Flannery

Field Summary

Fields
Modifier and Type	Field and Description
`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 File`	`dest_dir` Output directory.
`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 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 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 PrintWriter`	`symbol_class_file` Output file for the symbol constant class.
`protected static long`	`table_end` Timing data -- when did we end table construction

Method Summary

All Methods Static Methods Concrete Methods
Modifier and Type	Method and Description
`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(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(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 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 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(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 BufferedInputStream input_file
```
    Input file. This is a buffered version of System.in.
  - parser_class_file
```
protected static PrintWriter parser_class_file
```
    Output file for the parser class.
  - symbol_class_file
```
protected static PrintWriter symbol_class_file
```
    Output file for the symbol constant class.
  - dest_dir
```
protected static File dest_dir
```
    Output directory.
  - 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.
- Method Detail
  - main
```
public static void main(String[] argv)
                 throws internal_error,
                        IOException,
                        Exception
```
    The main driver for the system.
    
    Parameters:
    
    argv - an array of strings containing command line arguments.
    
    Throws:
    
    internal_error
    
    IOException
    
    Exception
  - usage
```
protected static void usage(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(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 IOException
```
    Close various files used by the system.
    
    Throws:
    
    IOException
  - parse_grammar_spec
```
protected static void parse_grammar_spec()
                                  throws 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:
    
    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 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 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

Class Main

Field Summary

Method Summary

Methods inherited from class java.lang.Object

Field Detail

print_progress

opt_dump_states

opt_dump_tables

opt_dump_grammar

opt_show_timing

opt_do_debug

opt_compact_red

include_non_terms

no_summary

expect_conflicts

lr_values

sym_interface

suppress_scanner

start_time

prelim_end

parse_end

check_end

dump_end

build_end

nullability_end

first_end

machine_end

table_end

reduce_check_end

emit_end

final_time

input_file

parser_class_file

symbol_class_file

dest_dir

start_state

action_table

reduce_table

Method Detail

main

usage

parse_args

open_files

close_files

parse_grammar_spec

check_unused

build_parser

emit_parser

plural

emit_summary

show_times

timestr

dump_grammar

dump_machine

dump_tables