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java: demonstrate push parsers

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* data/skeletons/lalr1.java (Location): Make it a static class.
(Lexer.yylex, Lexer.getLVal, Lexer.getStartPos, Lexer.getEndPos):
These are not needed in push parsers.
* examples/java/calc/Calc.y: Demonstrate push parsers in the Java.
* doc/bison.texi: Push parsers have been supported for a long time,
remove incorrect statements stating the opposite.
This commit is contained in:
Akim Demaille
2020-05-02 09:01:34 +02:00
parent ac2ba46053
commit 13a1537dba
6 changed files with 55 additions and 48 deletions
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43
data/skeletons/lalr1.java
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@@ -121,7 +121,7 @@ import java.text.MessageFormat;
* Locations represent a part of the input through the beginning
* and ending positions.
*/
public class ]b4_location_type[ {
public static class ]b4_location_type[ {
/**
* The first, inclusive, position in the range.
*/
@@ -182,8 +182,7 @@ import java.text.MessageFormat;
]b4_token_enums[
/** Deprecated, use ]b4_symbol(0, id)[ instead. */
public static final int EOF = ]b4_symbol(0, id)[;
]b4_locations_if([[
]b4_pull_if([b4_locations_if([[
/**
* Method to retrieve the beginning position of the last scanned token.
* @@return the position at which the last scanned token starts.
@@ -209,7 +208,7 @@ import java.text.MessageFormat;
* @@return the token identifier corresponding to the next token.
*/
int yylex()]b4_maybe_throws([b4_lex_throws])[;
]])[
/**
* Emit an error]b4_locations_if([ referring to the given location])[in a user-defined way.
*
@@ -832,7 +831,7 @@ b4_dollar_popdef[]dnl
this.push_parse_initialized = true;
}
]b4_locations_if([
]b4_locations_if([[
/**
* Push parse given input from an external lexer.
*
@@ -842,11 +841,10 @@ b4_dollar_popdef[]dnl
*
* @@return <tt>YYACCEPT, YYABORT, YYPUSH_MORE</tt>
*/
public int push_parse(int yylextoken, b4_yystype yylexval, b4_position_type yylexpos)b4_maybe_throws([b4_list2([b4_lex_throws], [b4_throws])])
{
return push_parse(yylextoken, yylexval, new b4_location_type (yylexpos));
public int push_parse(int yylextoken, ]b4_yystype[ yylexval, ]b4_position_type[ yylexpos)]b4_maybe_throws([b4_list2([b4_lex_throws], [b4_throws])])[ {
return push_parse(yylextoken, yylexval, new ]b4_location_type[(yylexpos));
}
])[]])[
]])])[
]b4_both_if([[
/**
@@ -857,21 +855,18 @@ b4_dollar_popdef[]dnl
* @@return <tt>true</tt> if the parsing succeeds. Note that this does not
* imply that there were no syntax errors.
*/
public boolean parse()]b4_maybe_throws([b4_list2([b4_lex_throws], [b4_throws])])[
{
if (yylexer == null)
throw new NullPointerException("Null Lexer");
int status;
do {
int token = yylexer.yylex();
]b4_yystype[ lval = yylexer.getLVal();
]b4_locations_if([dnl
b4_location_type yyloc = new b4_location_type (yylexer.getStartPos (),
yylexer.getEndPos ());])[]b4_locations_if([[
status = push_parse(token,lval,yyloc);]], [[
status = push_parse(token,lval);]])[
} while (status == YYPUSH_MORE);
return (status == YYACCEPT);
public boolean parse()]b4_maybe_throws([b4_list2([b4_lex_throws], [b4_throws])])[ {
if (yylexer == null)
throw new NullPointerException("Null Lexer");
int status;
do {
int token = yylexer.yylex();
]b4_yystype[ lval = yylexer.getLVal();]b4_locations_if([[
]b4_location_type[ yyloc = new ]b4_location_type[(yylexer.getStartPos(), yylexer.getEndPos());
status = push_parse(token, lval, yyloc);]], [[
status = push_parse(token, lval);]])[
} while (status == YYPUSH_MORE);
return status == YYACCEPT;
}
]])[