390 lines
3.6 KiB
ANTLR
390 lines
3.6 KiB
ANTLR
grammar SysY;
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program
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: compUnit
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;
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compUnit
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: (funcDef | decl)+
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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_KW bType constDef (COMMA constDef)* SEMICOLON
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;
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bType
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: INT_KW
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;
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constDef
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: IDENT (L_BRACKT constExp R_BRACKT)* ASSIGN constInitVal
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;
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constInitVal
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: constExp
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| (L_BRACE (constInitVal (COMMA constInitVal)*)? R_BRACE)
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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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varDef
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: IDENT (L_BRACKT constExp R_BRACKT)* (ASSIGN initVal)?
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;
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initVal
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: exp
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| (L_BRACE (initVal (COMMA initVal)*)? R_BRACE)
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;
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funcDef
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: funcType IDENT L_PAREN funcFParams? R_PAREN block
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;
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funcType
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: VOID_KW
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| INT_KW
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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 IDENT (L_BRACKT R_BRACKT (L_BRACKT exp R_BRACKT)*)?
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;
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block
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: L_BRACE blockItem* R_BRACE
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;
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blockItem
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: constDecl
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| varDecl
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| stmt
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;
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stmt
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: assignStmt
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| expStmt
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| block
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| conditionStmt
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| whileStmt
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| breakStmt
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| continueStmt
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| returnStmt
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;
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assignStmt
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: lVal ASSIGN exp SEMICOLON
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;
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expStmt
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: exp? SEMICOLON
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;
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conditionStmt
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: IF_KW L_PAREN cond R_PAREN stmt (ELSE_KW stmt)?
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;
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whileStmt
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: WHILE_KW L_PAREN cond R_PAREN stmt
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;
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breakStmt
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: BREAK_KW SEMICOLON
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;
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continueStmt
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: CONTINUE_KW SEMICOLON
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;
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returnStmt
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: RETURN_KW (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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lVal
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: IDENT (L_BRACKT exp R_BRACKT)*
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;
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primaryExp
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: (L_PAREN exp R_PAREN)
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| lVal
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| number
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;
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number
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: intConst
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;
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intConst
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: DECIMAL_CONST
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| OCTAL_CONST
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| HEXADECIMAL_CONST
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;
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unaryExp
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: primaryExp
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| callee
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| (unaryOp unaryExp)
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;
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callee
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: IDENT L_PAREN funcRParams? R_PAREN
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;
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unaryOp
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: PLUS
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| MINUS
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| NOT
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;
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funcRParams
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: param (COMMA param)*
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;
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param
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: exp
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| STRING
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;
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mulExp
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: unaryExp (mulOp unaryExp)*
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; // eliminate left-recursive
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mulOp
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: MUL
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| DIV
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| MOD
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;
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addExp
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: mulExp (addOp mulExp)*
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; // eliminate left-recursive
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addOp
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: PLUS
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| MINUS
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;
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relExp
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: addExp (relOp addExp)*
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; // eliminate left-recursive
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relOp
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: LT
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| GT
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| LE
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| GE
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;
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eqExp
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: relExp (eqOp relExp)*
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;
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eqOp
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: EQ
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| NEQ
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;
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lAndExp
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: eqExp (AND eqExp)*
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;
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lOrExp
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: lAndExp (OR lAndExp)*
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;
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constExp
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: addExp
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;
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CONST_KW
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: 'const'
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;
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INT_KW
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: 'int'
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;
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VOID_KW
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: 'void'
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;
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IF_KW
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: 'if'
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;
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ELSE_KW
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: 'else'
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;
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WHILE_KW
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: 'while'
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;
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BREAK_KW
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: 'break'
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;
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CONTINUE_KW
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: 'continue'
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;
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RETURN_KW
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: 'return'
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;
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IDENT
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: [_a-zA-Z]
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| [_a-zA-Z] [_a-zA-Z0-9]+
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;
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DECIMAL_CONST
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: [1-9]
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| [1-9] [0-9]+
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;
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OCTAL_CONST
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: '0'
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| ('0' [0-7]+)
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;
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HEXADECIMAL_CONST
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: ('0x' | '0X') [a-fA-F0-9]+
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;
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STRING
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: DOUBLE_QUOTE REGULAR_CHAR*? DOUBLE_QUOTE
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;
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fragment REGULAR_CHAR
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: (ESC | .)
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;
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fragment ESC
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: '\\"' | '\\\\'
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;
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PLUS
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: '+'
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;
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MINUS
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: '-'
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;
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NOT
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: '!'
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;
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MUL
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: '*'
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;
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DIV
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: '/'
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;
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MOD
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: '%'
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;
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ASSIGN
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: '='
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;
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EQ
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: '=='
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;
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NEQ
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: '!='
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;
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LT
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: '<'
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;
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GT
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: '>'
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;
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LE
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: '<='
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;
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GE
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: '>='
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;
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AND
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: '&&'
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;
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OR
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: '||'
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;
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L_PAREN
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: '('
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;
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R_PAREN
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: ')'
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;
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L_BRACE
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: '{'
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;
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R_BRACE
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: '}'
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;
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L_BRACKT
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: '['
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;
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R_BRACKT
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: ']'
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;
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COMMA
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: ','
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;
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SEMICOLON
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: ';'
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;
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DOUBLE_QUOTE
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: '"'
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;
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WS
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: [ \r\n\t]+ -> skip
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;
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LINE_COMMENT
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: '//' ~ [\r\n]* -> skip
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;
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MULTILINE_COMMENT
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: '/*' .*? '*/' -> skip
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;
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