253 lines
4.1 KiB
ANTLR
253 lines
4.1 KiB
ANTLR
// SysY 语法：扩展支持更多SysY特性
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grammar SysY;
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/*===-------------------------------------------===*/
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/* Lexer rules */
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/*===-------------------------------------------===*/
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// 关键字
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INT: 'int';
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FLOAT: 'float';
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VOID: 'void';
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CONST: 'const';
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RETURN: 'return';
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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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// 操作符
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ASSIGN: '=';
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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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LT: '<';
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LE: '<=';
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GT: '>';
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GE: '>=';
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EQ: '==';
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NE: '!=';
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// 逻辑操作符
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NOT: '!';
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AND: '&&';
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OR: '||';
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// 括号
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LPAREN: '(';
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RPAREN: ')';
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LBRACE: '{';
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RBRACE: '}';
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LBRACK: '[';
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RBRACK: ']';
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// 标点
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SEMICOLON: ';';
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COMMA: ',';
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// 标识符和字面量
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ID: [a-zA-Z_][a-zA-Z_0-9]*;
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ILITERAL
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: DECIMAL_LITERAL
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| OCTAL_LITERAL
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| HEX_LITERAL
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;
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fragment DECIMAL_LITERAL
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: [0-9]+
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;
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fragment OCTAL_LITERAL
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: '0' [0-7]+
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;
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fragment HEX_LITERAL
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: '0' ('x' | 'X') [0-9a-fA-F]+
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;
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// 浮点字面量
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FLITERAL
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: (DECIMAL_FLOAT | HEX_FLOAT)
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;
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fragment DECIMAL_FLOAT
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: ((DIGIT+ '.' DIGIT* | '.' DIGIT+)
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(('E' | 'e') ('+' | '-')? DIGIT+)?)
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| ((DIGIT+ '.' DIGIT* | '.' DIGIT+ | DIGIT+)
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(('E' | 'e') ('+' | '-')? DIGIT+))
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| ('0' [0-7]+ '.' [0-7]*
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(('E' | 'e') ('+' | '-')? DIGIT+)?)
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;
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fragment HEX_FLOAT
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: '0' ('x' | 'X')
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(HEXDIGIT* '.' HEXDIGIT+ | HEXDIGIT+ '.')
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(('P' | 'p') ('+' | '-')? DIGIT+)
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| '0' ('x' | 'X')
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HEXDIGIT+
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(('P' | 'p') ('+' | '-')? DIGIT+)
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;
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fragment DIGIT
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: [0-9]
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;
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fragment HEXDIGIT
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: [0-9a-fA-F]
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;
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// 空白和注释
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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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// 声明
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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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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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| VOID
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;
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constDef
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: ID (LBRACK exp RBRACK)* ASSIGN initValue
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;
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varDef
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: ID (LBRACK exp 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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// 函数定义
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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 (exp)? RBRACK)*
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;
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// 语句
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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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: assignStmt
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| returnStmt
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| blockStmt
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| ifStmt
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| whileStmt
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| breakStmt
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| continueStmt
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| expStmt
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;
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expStmt
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: exp SEMICOLON
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;
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assignStmt
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: lValue ASSIGN exp SEMICOLON
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;
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returnStmt
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: RETURN (exp)? SEMICOLON
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;
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ifStmt
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: IF LPAREN exp RPAREN stmt (ELSE stmt)?
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;
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whileStmt
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: WHILE LPAREN exp RPAREN stmt
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;
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breakStmt
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: BREAK SEMICOLON
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;
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continueStmt
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: CONTINUE SEMICOLON
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;
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// 表达式
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lValue
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: ID (LBRACK exp RBRACK)*
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;
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exp
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: LPAREN exp RPAREN # parenExp
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| lValue # lValueExp
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| number # numberExp
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| ID LPAREN (funcRParams)? RPAREN # funcCallExp
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| NOT exp # notExp
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| ADD exp # unaryAddExp
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| SUB exp # unarySubExp
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| exp MUL exp # mulExp
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| exp DIV exp # divExp
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| exp MOD exp # modExp
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| exp ADD exp # addExp
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| exp SUB exp # subExp
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| exp LT exp # ltExp
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| exp LE exp # leExp
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| exp GT exp # gtExp
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| exp GE exp # geExp
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| exp EQ exp # eqExp
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| exp NE exp # neExp
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| exp AND exp # andExp
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| exp OR exp # orExp
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;
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funcRParams
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: exp (COMMA exp)*
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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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