java_cup

Class emit

public class emit extends 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).

Version: last update: 11/25/95

Author: Scott Hudson

See Also: java_cup.main

Field Summary
static Stringaction_code
User declarations for direct inclusion in user action class.
static longaction_code_time
Time to produce action code class.
static longaction_table_time
Time to produce the action table.
static longgoto_table_time
Time to produce the reduce-goto table.
static Stackimport_list
List of imports (Strings containing class names) to go with actions.
static Stringinit_code
User code for user_init() which is called during parser initialization.
static intnot_reduced
Count of the number on non-reduced productions found.
static booleannowarn
Do we skip warnings?
static intnum_conflicts
Number of conflict found while building tables.
static Stringpackage_name
Package that the resulting code goes into (null is used for unnamed).
static Stringparser_class_name
Name of the generated parser class.
static Stringparser_code
User declarations for direct inclusion in parser class.
static longparser_time
Time to produce parser class.
static Stringprefix
The prefix placed on names that pollute someone else's name space.
static longproduction_table_time
Time to produce the production table.
static Stringscan_code
User code for scan() which is called to get the next Symbol.
static productionstart_production
The start production of the grammar.
static longsymbols_time
Time to produce symbol constant class.
static Stringsymbol_const_class_name
Name of the generated class for symbol constants.
static intunused_non_term
Count of unused non terminals.
static intunused_term
Count of unused terminals.
protected static boolean_lr_values
Method Summary
protected static voiddo_action_table(PrintWriter out, parse_action_table act_tab, boolean compact_reduces)
Emit the action table.
protected static intdo_escaped(PrintWriter out, char c)
protected static intdo_newline(PrintWriter out, int nchar, int nbytes)
protected static voiddo_reduce_table(PrintWriter out, parse_reduce_table red_tab)
Emit the reduce-goto table.
protected static voiddo_table_as_string(PrintWriter out, short[][] sa)
protected static voidemit_action_code(PrintWriter out, production start_prod)
Emit code for the non-public class holding the actual action code.
protected static voidemit_package(PrintWriter out)
Emit a package spec if the user wants one.
protected static voidemit_production_table(PrintWriter out)
Emit the production table.
static booleanlr_values()
whether or not to emit code for left and right values
static voidparser(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 Stringpre(String str)
Build a string with the standard prefix.
protected static voidset_lr_values(boolean b)
static voidsymbols(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.

Field Detail

action_code

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

action_code_time

public static long action_code_time
Time to produce action code class.

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.

import_list

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

init_code

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

not_reduced

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

nowarn

public static boolean nowarn
Do we skip warnings?

num_conflicts

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

package_name

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

parser_class_name

public static String parser_class_name
Name of the generated parser class.

parser_code

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

parser_time

public static long parser_time
Time to produce parser class.

prefix

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

production_table_time

public static long production_table_time
Time to produce the production table.

scan_code

public static 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.

symbols_time

public static long symbols_time
Time to produce symbol constant class.

symbol_const_class_name

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

unused_non_term

public static int unused_non_term
Count of unused non terminals.

unused_term

public static int unused_term
Count of unused terminals.

_lr_values

protected static boolean _lr_values

Method Detail

do_action_table

protected static void do_action_table(PrintWriter out, parse_action_table act_tab, boolean compact_reduces)
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?

do_escaped

protected static int do_escaped(PrintWriter out, char c)

do_newline

protected static int do_newline(PrintWriter out, int nchar, int nbytes)

do_reduce_table

protected static void do_reduce_table(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(PrintWriter out, short[][] sa)

emit_action_code

protected static void emit_action_code(PrintWriter out, production start_prod)
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.

emit_package

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

Parameters: out stream to produce output on.

emit_production_table

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

Parameters: out stream to produce output on.

lr_values

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

parser

public static void parser(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.

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?

pre

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

Parameters: str string to prefix.

set_lr_values

protected static void set_lr_values(boolean b)

symbols

public static void symbols(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?