shift reduce&& reduce reduce errors in build parser for python garmmer
- by user366580
i wanna build buttom up parser by java cup
i write code in java cup , it is for python language
so i used grammer was written in this site :
but not all grammer , i choice partial set ,just while , identifer
also i smiplified them
when i did compile for the java cup that i write
by write this command in command prompt window :
java java_cup.Main -parser CalcParser -symbols CalcSymbol < javacupfile.cup
i get conflict errors ,they are of type reduce-shift conflict and reduce-reduce conflict
you can see to print screen of the errors in these links
image 1
click here to see imge1
the grammer was in EBNF form in as refernce site and
i convert it to BNF form
maybe i make mistake in converting so i get such errors
the origanl grammmer was
// grammer in EBNF form
identifier ::= (letter|"_") (letter | digit | "_")*
letter ::= lowercase | uppercase
lowercase ::= "a"..."z"
uppercase ::= "A"..."Z"
digit ::= "0"..."9
compound_stmt ::= if_stmt
| while_stmt
for_stmt ::=
"for" target_list "in" expression_list
":" suite
["else" ":" suite]
while_stmt ::= "while" expression ":" suite ["else" ":" suite]
suite ::= stmt_list NEWLINE
stmt_list ::= simple_stmt (";" simple_stmt)* [";"]
simple_stmt ::= expression_stmt
expression_stmt ::= expression_list
expression_list ::= expression ( "," expression )* [","]
expression ::= conditional_expression
conditional_expression ::= or_test ["if" or_test "else" expression]
or_test ::= and_test | or_test "or" and_test
and_test ::= not_test | and_test "and" not_test
not_test ::= comparison | "not" not_test
comparison ::= or_expr ( comp_operator or_expr )*
comp_operator ::= "<" | ">" | "==" | ">=" | "<=" | "<>" | "!="
| "is" ["not"] | ["not"] "in"
or_expr ::= xor_expr | or_expr "|" xor_expr
xor_expr ::= and_expr | xor_expr "^" and_expr
and_expr ::= "&" | and_expr
the grammer after converting to BNF form
identifier ::=letterletter| letterdigit| letter"_"| "_"letter | "_"digit | "_""_"
letter ::= lowercase | uppercase
lowercase ::= "a"..."z"
uppercase ::= "A"..."Z"
digit ::= "0"..."9
while_stmt ::= "while" expression ":" suite "else" ":" suite
|"while" expression ":" suite
suite ::= stmt_list NEWLINE
stmt_list ::= simple_stmt ";" simple_stmt stmt_list|";"
simple_stmt ::= expression_stmt
expression_stmt ::= expression_list
expression_list ::= expression "," expression expression_list| ","
expression ::= conditional_expression
conditional_expression ::= or_test "if" or_test "else" expression
|or_test
or_test ::= and_test | or_test "or" and_test
and_test ::= not_test | and_test "and" not_test
not_test ::= comparison | "not" not_test
comparison ::= or_expr comp_operator or_expr
comp_operator ::= "<" | ">" | "==" | ">=" | "<=" | "<>" | "!="
| "is" ["not"] | ["not"] "in"
or_expr ::= xor_expr | or_expr "|" xor_expr
xor_expr ::= and_expr | xor_expr "^" and_expr
and_expr ::= "&" | and_expr
and the java cup file that i compile and get those errors is
import java.io.*;
terminal COMA;
terminal ELSE;
terminal WHILE;
terminal NEWLINE;
terminal SEMCOLON;
terminal CAMMA;
terminal IF;
terminal OR;
terminal AND;
terminal NOT;
terminal LESS;
terminal GREATER;
terminal EQUAL;
terminal GREATERorE;
terminal LESSorE;
terminal NEQUAL;
terminal OROP;
terminal XOROP;
terminal ANDOP;
terminal Integer DIGIT;
terminal java.lang.String LOWERCASE;
terminal java.lang.String UPPERCASE;
non terminal java.lang.String IDENTIFIER;
non terminal java.lang.String LETTER;
non terminal COMPOUND_STMT;
non terminal WHILE_STMT;
non terminal EXPRESSION;
non terminal SUITE ;
non terminal STMT_LIST;
non terminal SIMPLE_STMT;
non terminal EXPRESSION_STMT;
non terminal EXPRESSION_LIST;
non terminal CONDITITONAL_EXPRESSION;
non terminal OR_TEST;
non terminal AND_TEST;
non terminal NOT_TEST;
non terminal COMPARISON;
non terminal COMP_OPERATOR;
non terminal OR_EXPR;
non terminal XOR_EXPR;
non terminal AND_EXPR;
IDENTIFIER ::=LETTER{: System.out.printf("lowercase"); :}|
{: System.out.printf("uppercase"); :}
LETTER{: System.out.printf("lowercase"); :}|
{: System.out.printf("uppercase"); :}| LETTER{: System.out.printf("lowercase"); :}|
{: System.out.printf("uppercase"); :} DIGIT;
LETTER ::= LOWERCASE | UPPERCASE;
COMPOUND_STMT ::=WHILE_STMT;
WHILE_STMT ::= WHILE{: System.out.printf( "while"); :}
EXPRESSION COMA {: System.out.printf(":"); :}
SUITE ELSE {: System.out.printf("else" ); :}
COMA{: System.out.printf( ":" ); :} SUITE
|WHILE{: System.out.printf( "while" ); :} EXPRESSION
COMA{: System.out.printf( ":" ); :} SUITE;
SUITE ::= STMT_LIST NEWLINE{: System.out.printf( "newline" ); :};
STMT_LIST ::= SIMPLE_STMT SEMCOLON{: System.out.printf( ";" ); :}
SIMPLE_STMT STMT_LIST|SEMCOLON{: System.out.printf( ";" ); :};
SIMPLE_STMT ::=EXPRESSION_STMT;
EXPRESSION_STMT ::=EXPRESSION_LIST;
EXPRESSION_LIST ::= EXPRESSION CAMMA{: System.out.printf( "," ); :}
EXPRESSION EXPRESSION_LIST| CAMMA{: System.out.printf( "," ); :};
EXPRESSION ::= CONDITITONAL_EXPRESSION;
CONDITITONAL_EXPRESSION ::= OR_TEST IF{: System.out.printf( "if"); :}
OR_TEST ELSE{: System.out.printf("else"); :} EXPRESSION
|OR_TEST;
OR_TEST ::= AND_TEST | OR_TEST OR{: System.out.printf( "or"); :} AND_TEST;
AND_TEST ::= NOT_TEST | AND_TEST AND{: System.out.printf( "and"); :} NOT_TEST;
NOT_TEST ::= COMPARISON | NOT{: System.out.printf("not"); :} NOT_TEST;
COMPARISON ::= OR_EXPR COMP_OPERATOR OR_EXPR ;
COMP_OPERATOR ::= LESS{: System.out.printf( "<"); :}
| GREATER{: System.out.printf(">"); :}
| EQUAL{: System.out.printf("=="); :}
| GREATERorE{: System.out.printf(">="); :}
| LESSorE{: System.out.printf("<="); :}
| NEQUAL{: System.out.printf("!="); :};
OR_EXPR ::= XOR_EXPR | OR_EXPR OROP{: System.out.printf("|"); :} XOR_EXPR;
XOR_EXPR ::= AND_EXPR | XOR_EXPR XOROP {: System.out.printf("^"); :}XOR_EXPR;
AND_EXPR ::= ANDOP{: System.out.printf("&"); :} | AND_EXPR;
can any one told me how can solve this errors to build parser correcrtly??
