Package java_cup
Class emit
java.lang.Object
java_cup.emit
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:
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Field Summary
FieldsModifier and TypeFieldDescriptionstatic String
User declarations for direct inclusion in user action class.static long
Time to produce action code class.static long
Time to produce the action table.static long
Time to produce the reduce-goto table.static Stack
List of imports (Strings containing class names) to go with actions.static String
User code for user_init() which is called during parser initialization.static int
Count of the number on non-reduced productions found.static boolean
Do we skip warnings?static int
Number of conflict found while building tables.static String
Package that the resulting code goes into (null is used for unnamed).static String
Name of the generated parser class.static String
User declarations for direct inclusion in parser class.static long
Time to produce parser class.static String
The prefix placed on names that pollute someone else's name space.static long
Time to produce the production table.static String
User code for scan() which is called to get the next token.static production
The start production of the grammar.static String
Name of the generated class for symbol constants.static long
Time to produce symbol constant class.static int
Count of unused non terminals.static int
Count of unused terminals. -
Method Summary
Modifier and TypeMethodDescriptionprotected static void
do_action_table
(PrintStream out, parse_action_table act_tab, boolean compact_reduces) Emit the action table.protected static void
do_reduce_table
(PrintStream out, parse_reduce_table red_tab) Emit the reduce-goto table.protected static void
emit_action_code
(PrintStream out, production start_prod) Emit code for the non-public class holding the actual action code.protected static void
emit_package
(PrintStream out) Emit a package spec if the user wants one.protected static void
Emit the production table.static void
parser
(PrintStream out, parse_action_table action_table, parse_reduce_table reduce_table, int start_st, production start_prod, boolean compact_reduces) Emit the parser subclass with embedded tables.protected static String
Build a string with the standard prefix.static void
symbols
(PrintStream out, boolean emit_non_terms) Emit code for the symbol constant class, optionally including non terms, if they have been requested.
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Field Details
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prefix
The prefix placed on names that pollute someone else's name space. -
package_name
Package that the resulting code goes into (null is used for unnamed). -
symbol_const_class_name
Name of the generated class for symbol constants. -
parser_class_name
Name of the generated parser class. -
action_code
User declarations for direct inclusion in user action class. -
parser_code
User declarations for direct inclusion in parser class. -
init_code
User code for user_init() which is called during parser initialization. -
scan_code
User code for scan() which is called to get the next token. -
start_production
The start production of the grammar. -
import_list
List of imports (Strings containing class names) to go with actions. -
num_conflicts
public static int num_conflictsNumber of conflict found while building tables. -
nowarn
public static boolean nowarnDo we skip warnings? -
not_reduced
public static int not_reducedCount of the number on non-reduced productions found. -
unused_term
public static int unused_termCount of unused terminals. -
unused_non_term
public static int unused_non_termCount of unused non terminals. -
symbols_time
public static long symbols_timeTime to produce symbol constant class. -
parser_time
public static long parser_timeTime to produce parser class. -
action_code_time
public static long action_code_timeTime to produce action code class. -
production_table_time
public static long production_table_timeTime to produce the production table. -
action_table_time
public static long action_table_timeTime to produce the action table. -
goto_table_time
public static long goto_table_timeTime to produce the reduce-goto table.
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Method Details
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pre
Build a string with the standard prefix.- Parameters:
str
- string to prefix.
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emit_package
Emit a package spec if the user wants one.- Parameters:
out
- stream to produce output on.
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symbols
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?
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emit_action_code
protected static void emit_action_code(PrintStream 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
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emit_production_table
Emit the production table.- Parameters:
out
- stream to produce output on.
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do_action_table
protected static void do_action_table(PrintStream 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
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do_reduce_table
Emit the reduce-goto table.- Parameters:
out
- stream to produce output on.red_tab
- the internal representation of the reduce-goto table.
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parser
public static void parser(PrintStream out, parse_action_table action_table, parse_reduce_table reduce_table, int start_st, production start_prod, boolean compact_reduces) 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?- Throws:
internal_error
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