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238 lines
3.4 KiB
238 lines
3.4 KiB
// SysY Lab1 语法：覆盖常见声明、控制流、数组、函数与表达式优先级。
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grammar SysY;
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/*===-------------------------------------------===*/
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/* Lexer rules */
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/*===-------------------------------------------===*/
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CONST: 'const';
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INT: 'int';
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FLOAT: 'float';
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VOID: 'void';
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IF: 'if';
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ELSE: 'else';
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WHILE: 'while';
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BREAK: 'break';
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CONTINUE: 'continue';
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RETURN: 'return';
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ASSIGN: '=';
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EQ: '==';
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NE: '!=';
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LT: '<';
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GT: '>';
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LE: '<=';
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GE: '>=';
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ADD: '+';
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SUB: '-';
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MUL: '*';
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DIV: '/';
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MOD: '%';
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NOT: '!';
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AND: '&&';
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OR: '||';
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LPAREN: '(';
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RPAREN: ')';
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LBRACK: '[';
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RBRACK: ']';
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LBRACE: '{';
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RBRACE: '}';
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COMMA: ',';
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SEMICOLON: ';';
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ID: [a-zA-Z_][a-zA-Z_0-9]*;
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FLITERAL
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: DECIMAL_FLOAT
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| HEX_FLOAT
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;
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ILITERAL
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: HEX_INT
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| OCT_INT
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| DEC_INT
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;
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fragment DEC_INT: '0' | [1-9] [0-9]*;
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fragment OCT_INT: '0' [0-7]+;
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fragment HEX_INT: '0' [xX] [0-9a-fA-F]+;
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fragment DECIMAL_FLOAT
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: [0-9]+ '.' [0-9]* EXP?
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| '.' [0-9]+ EXP?
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| [0-9]+ EXP
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;
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fragment HEX_FLOAT
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: '0' [xX] [0-9a-fA-F]+ ('.' [0-9a-fA-F]*)? [pP] [+-]? [0-9]+
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| '0' [xX] '.' [0-9a-fA-F]+ [pP] [+-]? [0-9]+
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;
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fragment EXP: [eE] [+-]? [0-9]+;
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WS: [ \t\r\n] -> skip;
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LINECOMMENT: '//' ~[\r\n]* -> skip;
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BLOCKCOMMENT: '/*' .*? '*/' -> skip;
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/*===-------------------------------------------===*/
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/* Syntax rules */
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/*===-------------------------------------------===*/
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compUnit
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: (decl | funcDef)+ EOF
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;
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decl
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: constDecl
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| varDecl
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;
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constDecl
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: CONST btype constDef (COMMA constDef)* SEMICOLON
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;
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constDef
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: ID (LBRACK constExp RBRACK)* ASSIGN constInitValue
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;
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constInitValue
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: constExp
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| LBRACE (constInitValue (COMMA constInitValue)*)? RBRACE
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;
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varDecl
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: btype varDef (COMMA varDef)* SEMICOLON
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;
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btype
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: INT
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| FLOAT
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;
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varDef
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: ID (LBRACK constExp RBRACK)* (ASSIGN initValue)?
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;
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initValue
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: exp
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| LBRACE (initValue (COMMA initValue)*)? RBRACE
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;
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funcDef
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: funcType ID LPAREN (funcFParams)? RPAREN blockStmt
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;
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funcType
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: INT
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| FLOAT
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| VOID
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;
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funcFParams
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: funcFParam (COMMA funcFParam)*
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;
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funcFParam
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: btype ID (LBRACK RBRACK (LBRACK exp RBRACK)*)?
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;
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blockStmt
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: LBRACE blockItem* RBRACE
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;
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blockItem
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: decl
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| stmt
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;
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stmt
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: lValue ASSIGN exp SEMICOLON
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| (exp)? SEMICOLON
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| blockStmt
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| IF LPAREN cond RPAREN stmt (ELSE stmt)?
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| WHILE LPAREN cond RPAREN stmt
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| BREAK SEMICOLON
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| CONTINUE SEMICOLON
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| returnStmt
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;
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returnStmt
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: RETURN (exp)? SEMICOLON
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;
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exp
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: addExp
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;
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cond
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: lOrExp
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;
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lValue
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: ID (LBRACK exp RBRACK)*
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;
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primaryExp
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: LPAREN exp RPAREN
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| lValue
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| number
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;
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number
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: ILITERAL
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| FLITERAL
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;
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unaryExp
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: primaryExp
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| ID LPAREN (funcRParams)? RPAREN
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| unaryOp unaryExp
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;
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unaryOp
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: ADD
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| SUB
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| NOT
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;
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funcRParams
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: exp (COMMA exp)*
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;
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mulExp
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: unaryExp
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| mulExp (MUL | DIV | MOD) unaryExp
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;
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addExp
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: mulExp
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| addExp (ADD | SUB) mulExp
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;
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relExp
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: addExp
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| relExp (LT | GT | LE | GE) addExp
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;
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eqExp
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: relExp
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| eqExp (EQ | NE) relExp
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;
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lAndExp
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: eqExp
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| lAndExp AND eqExp
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;
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lOrExp
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: lAndExp
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| lOrExp OR lAndExp
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;
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constExp
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: addExp
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;
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