java_cup
Class emit

java.lang.Object
  extended byjava_cup.emit

public class emit
extends java.lang.Object

This class handles emitting generated code for the resulting parser. The various parse tables must be constructed, etc. before calling any routines in this class.

Three classes are produced by this code:

symbol constant class
this contains constant declarations for each terminal (and optionally each non-terminal).
action class
this non-public class contains code to invoke all the user actions that were embedded in the parser specification.
parser class
the specialized parser class consisting primarily of some user supplied general and initialization code, and the parse tables.

Three parse tables are created as part of the parser class:

production table
lists the LHS non terminal number, and the length of the RHS of each production.
action table
for each state of the parse machine, gives the action to be taken (shift, reduce, or error) under each lookahead symbol.
reduce-goto table
when a reduce on a given production is taken, the parse stack is popped back a number of elements corresponding to the RHS of the production. This reveals a prior state, which we transition out of under the LHS non terminal symbol for the production (as if we had seen the LHS symbol rather than all the symbols matching the RHS). This table is indexed by non terminal numbers and indicates how to make these transitions.

In addition to the method interface, this class maintains a series of public global variables and flags indicating how misc. parts of the code and other output is to be produced, and counting things such as number of conflicts detected (see the source code and public variables below for more details).

This class is "static" (contains only static data and methods).

See Also:
java_cup.main

Field Summary
protected static boolean _lr_values
           
static java.lang.String action_code
          User declarations for direct inclusion in user action class.
static long action_code_time
          Time to produce action code class.
static long action_table_time
          Time to produce the action table.
static long goto_table_time
          Time to produce the reduce-goto table.
static java.util.Stack import_list
          List of imports (Strings containing class names) to go with actions.
static java.lang.String init_code
          User code for user_init() which is called during parser initialization.
static int not_reduced
          Count of the number on non-reduced productions found.
static boolean nowarn
          Do we skip warnings?
static int num_conflicts
          Number of conflict found while building tables.
static java.lang.String package_name
          Package that the resulting code goes into (null is used for unnamed).
static java.lang.String parser_class_name
          Name of the generated parser class.
static java.lang.String parser_code
          User declarations for direct inclusion in parser class.
static long parser_time
          Time to produce parser class.
static java.lang.String prefix
          The prefix placed on names that pollute someone else's name space.
static long production_table_time
          Time to produce the production table.
static java.lang.String scan_code
          User code for scan() which is called to get the next Symbol.
static production start_production
          The start production of the grammar.
static java.lang.String symbol_const_class_name
          Name of the generated class for symbol constants.
static long symbols_time
          Time to produce symbol constant class.
static int unused_non_term
          Count of unused non terminals.
static int unused_term
          Count of unused terminals.
 
Constructor Summary
private emit()
          Only constructor is private so no instances can be created.
 
Method Summary
protected static void do_action_table(java.io.PrintWriter out, parse_action_table act_tab, boolean compact_reduces)
          Emit the action table.
protected static int do_escaped(java.io.PrintWriter out, char c)
           
protected static int do_newline(java.io.PrintWriter out, int nchar, int nbytes)
           
protected static void do_reduce_table(java.io.PrintWriter out, parse_reduce_table red_tab)
          Emit the reduce-goto table.
protected static void do_table_as_string(java.io.PrintWriter out, short[][] sa)
           
protected static void emit_action_code(java.io.PrintWriter out, production start_prod)
          Emit code for the non-public class holding the actual action code.
protected static void emit_package(java.io.PrintWriter out)
          Emit a package spec if the user wants one.
protected static void emit_production_table(java.io.PrintWriter out)
          Emit the production table.
static boolean lr_values()
          whether or not to emit code for left and right values
static void parser(java.io.PrintWriter out, parse_action_table action_table, parse_reduce_table reduce_table, int start_st, production start_prod, boolean compact_reduces, boolean suppress_scanner)
          Emit the parser subclass with embedded tables.
protected static java.lang.String pre(java.lang.String str)
          Build a string with the standard prefix.
protected static void set_lr_values(boolean b)
           
static void symbols(java.io.PrintWriter out, boolean emit_non_terms, boolean sym_interface)
          Emit code for the symbol constant class, optionally including non terms, if they have been requested.
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Field Detail

prefix

public static java.lang.String prefix
The prefix placed on names that pollute someone else's name space.


package_name

public static java.lang.String package_name
Package that the resulting code goes into (null is used for unnamed).


symbol_const_class_name

public static java.lang.String symbol_const_class_name
Name of the generated class for symbol constants.


parser_class_name

public static java.lang.String parser_class_name
Name of the generated parser class.


action_code

public static java.lang.String action_code
User declarations for direct inclusion in user action class.


parser_code

public static java.lang.String parser_code
User declarations for direct inclusion in parser class.


init_code

public static java.lang.String init_code
User code for user_init() which is called during parser initialization.


scan_code

public static java.lang.String scan_code
User code for scan() which is called to get the next Symbol.


start_production

public static production start_production
The start production of the grammar.


import_list

public static java.util.Stack import_list
List of imports (Strings containing class names) to go with actions.


num_conflicts

public static int num_conflicts
Number of conflict found while building tables.


nowarn

public static boolean nowarn
Do we skip warnings?


not_reduced

public static int not_reduced
Count of the number on non-reduced productions found.


unused_term

public static int unused_term
Count of unused terminals.


unused_non_term

public static int unused_non_term
Count of unused non terminals.


symbols_time

public static long symbols_time
Time to produce symbol constant class.


parser_time

public static long parser_time
Time to produce parser class.


action_code_time

public static long action_code_time
Time to produce action code class.


production_table_time

public static long production_table_time
Time to produce the production table.


action_table_time

public static long action_table_time
Time to produce the action table.


goto_table_time

public static long goto_table_time
Time to produce the reduce-goto table.


_lr_values

protected static boolean _lr_values
Constructor Detail

emit

private emit()
Only constructor is private so no instances can be created.

Method Detail

lr_values

public static boolean lr_values()
whether or not to emit code for left and right values


set_lr_values

protected static void set_lr_values(boolean b)

pre

protected static java.lang.String pre(java.lang.String str)
Build a string with the standard prefix.

Parameters:
str - string to prefix.

emit_package

protected static void emit_package(java.io.PrintWriter out)
Emit a package spec if the user wants one.

Parameters:
out - stream to produce output on.

symbols

public static void symbols(java.io.PrintWriter out,
                           boolean emit_non_terms,
                           boolean sym_interface)
Emit code for the symbol constant class, optionally including non terms, if they have been requested.

Parameters:
out - stream to produce output on.
emit_non_terms - do we emit constants for non terminals?
sym_interface - should we emit an interface, rather than a class?

emit_action_code

protected static void emit_action_code(java.io.PrintWriter out,
                                       production start_prod)
                                throws internal_error
Emit code for the non-public class holding the actual action code.

Parameters:
out - stream to produce output on.
start_prod - the start production of the grammar.
Throws:
internal_error

emit_production_table

protected static void emit_production_table(java.io.PrintWriter out)
Emit the production table.

Parameters:
out - stream to produce output on.

do_action_table

protected static void do_action_table(java.io.PrintWriter out,
                                      parse_action_table act_tab,
                                      boolean compact_reduces)
                               throws internal_error
Emit the action table.

Parameters:
out - stream to produce output on.
act_tab - the internal representation of the action table.
compact_reduces - do we use the most frequent reduce as default?
Throws:
internal_error

do_reduce_table

protected static void do_reduce_table(java.io.PrintWriter out,
                                      parse_reduce_table red_tab)
Emit the reduce-goto table.

Parameters:
out - stream to produce output on.
red_tab - the internal representation of the reduce-goto table.

do_table_as_string

protected static void do_table_as_string(java.io.PrintWriter out,
                                         short[][] sa)

do_newline

protected static int do_newline(java.io.PrintWriter out,
                                int nchar,
                                int nbytes)

do_escaped

protected static int do_escaped(java.io.PrintWriter out,
                                char c)

parser

public static void parser(java.io.PrintWriter out,
                          parse_action_table action_table,
                          parse_reduce_table reduce_table,
                          int start_st,
                          production start_prod,
                          boolean compact_reduces,
                          boolean suppress_scanner)
                   throws internal_error
Emit the parser subclass with embedded tables.

Parameters:
out - stream to produce output on.
action_table - internal representation of the action table.
reduce_table - internal representation of the reduce-goto table.
start_st - start state of the parse machine.
start_prod - start production of the grammar.
compact_reduces - do we use most frequent reduce as default?
suppress_scanner - should scanner be suppressed for compatibility?
Throws:
internal_error