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# # ======= Expression Grammar Productions (3rd Approach) - 22/12/2013 ======= # # Basics Digit ::= '0' | ... | '9' Letter ::= 'a' | ... | 'z' | 'A' | ... | 'Z' Number ::= Digit ( Digit )* Identifier ::= ( '_' | Letter ) ( '_' | Letter | Digit )* # Literals Literal ::= IntLiteral IntLiteral ::= Number FloatLiteral ::= Number '.' Number BoolLitearl ::= 'true' | 'false' # Object identifiers ArrayIndex ::= ArithmeticExpr ObjectName ::= Identifier ( '.' Identifier )* Object ::= ObjectName ( '[' ArrayIndex ']' )* # Function arguments ArgList ::= epsilon | SingleArg ( ',' SingleArg )* SingleArg ::= BooleanExpr | ArithmeticExpr # Sum expressions ArithmeticExpr ::= SumExpr SumExpr ::= ProductExpr ( ( '+' | '-' ) ProductExpr )* ProductExpr ::= ValueExpr ( ( '*' | '/' | '%' ) ValueExpr )* ValueExpr ::= Literal | MemoryObject | BracketExpr | CastExpr | CallExpr BracketExpr ::= '(' ArithmeticExpr ')' CastExpr ::= '(' TypeDenoter ')' ValueExpr CallExpr ::= ObjectName '(' ArgList ')' # Bool expressions BooleanExpr ::= LinkedOrExpr LinkedOrExpr ::= LinkedAndExpr ( '||' LinkedAndExpr )* LinkedAndExpr ::= ValueBoolExpr ( '&&' ValueBoolExpr )* ValueBoolExpr ::= BoolLitearl | RelationExpr | NegBoolExpr RelationExpr ::= ArithmeticExpr ( '=' | '!=' | '<' | '>' | '<=' | '>=' ) ArithmeticExpr NegBoolExpr ::= '!' BooleanExpr # Assignment statements MemoryObject ::= ObjectName | AssignStatement AssignStatement ::= LeftAssign | IncDecAssign LeftAssign ::= MemoryObject ( ':=' | '+=' | '-=' | '*=' | '/=' | '%=' | '|=' | '&=' | '^=' | '<<=' | '>>=' ) ( BooleanExpr | ArithmeticExpr ) IncDecAssign ::= PreIncDecAssign | PostIncDecAssign PreIncDecAssign ::= ( '++' | '--' ) MemoryObject PostIncDecAssign ::= MemoryObject ( '++' | '--' ) # === Use case example (Pseudo Code) === # Example code (of my language): # # if x + 2 > 3 - (2 + func(x - 2, true)) * y { # x := 2 + ++y - func(y, false) # i++ # } # AcceptToken(Type) { if (CurrentTokenType == Type) GetNextToken() else Error() } ParseIfStatement() { AcceptToken('if') ParseBooleanExpression() ParseStatementBlock() } ParseStatementBlock() { AcceptToken('{') while (CurrentTokenType != '}') { ParseStatement() } AcceptToken('}') } |
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ParseIfStatement() {
AcceptToken('if')
ParseBooleanExpression()
ParseStatementBlock()
}
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Dieser Beitrag wurde bereits 1 mal editiert, zuletzt von »Toa« (23.12.2013, 09:00)
Was für eine Art Parser bastelst du denn?
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int x int x() |
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Program ::= ( Command )* // "Program" ist das Start-Symbol CommandBlock ::= '{' ( Command )* '}' Command ::= IfCommand | ClassDeclaration | CommandBlock | EnumerationDefinition IfCommand ::= 'if' BooleanExpression CommandBlock ( 'elif' BooleanExpression CommandBlock )* ( epsilon | 'else' CommandBlock ) ClassDeclaration ::= 'class' Identifier ClassCommandBlock ClassCommandBlock ::= '{' ( ClassCommand )* '}' ClassCommand ::= ClassDeclaration | PrivacySpecifier | EnumerationDefinition PrivacySpecifier ::= 'public:' | 'private:' | 'protected:' EnumerationDefinition ::= 'enum' Identifier EnumerationBlock EnumerationBlock ::= '{' ( Identifier )* '}' |
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# Basics Digit ::= '0' | ... | '9' Letter ::= 'a' | ... | 'z' | 'A' | ... | 'Z' Number ::= Digit ( Digit )* Identifier ::= ( '_' | Letter ) ( '_' | Letter | Digit )* # Literals Literal ::= IntLiteral | FloatLiteral | BoolLiteral IntLiteral ::= Number FloatLiteral ::= Number '.' Number BoolLitearl ::= 'true' | 'false' StringLiteral ::= '"' ( AnyCharacter )* '"' ArithmeticLiteral ::= IntLiteral | FloatLiteral # Object identifiers ArrayIndex ::= ArithmeticExpr ObjectName ::= Identifier ( '.' Identifier )* Object ::= ObjectName ( '[' ArrayIndex ']' )* # Arithmetic expressions ArithmeticExpr ::= BitwiseOrExpr BitwiseOrExpr ::= BitwiseXorExpr ( '|' BitwiseXorExpr )* BitwiseXorExpr ::= BitwiseAndExpr ( '^' BitwiseAndExpr )* BitwiseAndExpr ::= ShiftExpr ( '&' ShiftExpr )* ShiftExpr ::= SumExpr ( ( '<<' | '>>' ) SumExpr )* SumExpr ::= ProductExpr ( ( '+' | '-' ) ProductExpr )* ProductExpr ::= ValueExpr ( ( '*' | '/' | '%' ) ValueExpr )* ValueExpr ::= ArithmeticLiteral | MemoryObject | ArithmeticBracketExpr | CastExpr | CallExpr ArithmeticBracketExpr ::= '(' ArithmeticExpr ')' CastExpr ::= '(' TypeDenoter ')' ValueExpr CallExpr ::= ObjectName '(' ArgList ')' # Assignment statements MemoryObject ::= Object | AssignStatement AssignStatement ::= LeftAssign | IncDecAssign LeftAssign ::= MemoryObject ( ':=' | '+=' | '-=' | '*=' | '/=' | '%=' | '|=' | '&=' | '^=' | '<<=' | '>>=' ) ( BooleanExpr | ArithmeticExpr ) IncDecAssign ::= PreIncDecAssign | PostIncDecAssign PreIncDecAssign ::= ( '++' | '--' ) MemoryObject PostIncDecAssign ::= MemoryObject ( '++' | '--' ) |
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// ----- PSEUDOCODE for Expression Parsing ----- ParseArithmeticExpr() { return ParseBitwiseOrExpr(); } ParseBitwiseOrExpr() { auto ExprAST = new BitwiseOrExpression; ExprAST->XorExprList.push_back(ParseBitwiseXorExpr()); while (TokenType() == '|') { AcceptIt(); ExprAST->XorExprList.push_back(ParseBitwiseXorExpr()); } return ExprAST; } ParseBitwiseXorExpr() { auto ExprAST = new BitwiseXorExpression; ExprAST->AndExprList.push_back(ParseBitwiseAndExpr()); while (TokenType() == '^') { AcceptIt(); ExprAST->AndExprList.push_back(ParseBitwiseAndExpr()); } return ExprAST; } ParseBitwiseAndExpr() { auto ExprAST = new BitwiseAndExpression; ExprAST->ShiftExprList.push_back(ParseShiftExpr()); while (TokenType() == '&') { AcceptIt(); ExprAST->ShiftExprList.push_back(ParseShiftExpr()); } return ExprAST; } ParseShiftExpr() { auto ExprAST = new ShiftExpression; ExprAST->SumExprList.push_back(ParseSumExpr()); while (TokenType() == '<<' || TokenType() == '>>') { AcceptIt(); ExprAST->SumExprList.push_back(ParseSumExpr()); } return ExprAST; } ParseSumExpr() { auto ExprAST = new SumExpression; ExprAST->ProductExprList.push_back(ParseProductExpr()); while (TokenType() == '+' || TokenType() == '-') { AcceptIt(); ExprAST->ProductExprList.push_back(ParseProductExpr()); } return ExprAST; } ParseProductExpr() { auto ExprAST = new ProductExpression; ExprAST->SumExprList.push_back(ParseValueExpr()); while (TokenType() == '*' || TokenType() == '/' || TokenType() == '%') { AcceptIt(); ExprAST->SumExprList.push_back(ParseValueExpr()); } return ExprAST; } ParseValueExpr() { auto ExprAST = new ValueExpression; switch (TokenType()) { case IntLiteral: case FloatLiteral: return ParseArithmeticLiteral(); case '(': return ParseArithmeticBracketExprOrCastExpr(); case Identifer: return ParseMemoryObjectOrCallExpr(); default: ErrorUnexpectedToken(); } return ExprAST; } ParseArithmeticBracketExprOrCastExpr() { // Store information where we are currently reading in file. Scanner_.PushPos(); // Try to parse a cast expression ('false' means it is not required). auto CastExprAST = ParseCastExpr(false); if (CastExprAST == nullptr) { // Restore position we were reading before trying to find a cast expression. Scanner_.PopPosAndRestore(); // Now try to parse bracket expression. return ParseArithmeticBracketExpr(); } else { // Pop stored position from the scanner's stack and continue reading by ignoring the poped data. Scanner_.PopPosAndIgnore(); return CastExprAST; } } ParseCastExpr(bool Required) { if (TokenType() == '(') AcceptIt(); else { if (Required) ErrorUnexpectedToken("Expected '('"); return nullptr; } // Parse type denoter to which the value expression is to be casted. auto TypeDenoterAST = ParseTypeDenoter(Required); if (TypeDenoterAST == nullptr) return nullptr; if (TokenType() == ')') AcceptIt(); else { if (Required) ErrorUnexpectedToken("Expected ')'"); return nullptr; } // Parse the value expression which is to be casted. auto ValueExprAST = ParseValueExpr(); auto CastExprAST = new CastExpression; CastExprAST->TypeDenoter = TypeDenoterAST; CastExprAST->ValueExpr = ValueExprAST; return CastExprAST; } ParseArithmeticBracketExpr() { auto ExprAST = new ArithmeticBracketExpr; Accept('('); { ExprAST->ArithmeticExpr = ParseArithmeticExpr(); } Accept(')'); return ExprAST; } ParseMemoryObjectOrCallExpr() { // For memory object and call epxression we need an object-name AST node auto ObjectNameAST = ParseObjectName(); if (TokenType() == '(') { // If the object name is followed by a '(' character it must be a function call. return ParseCallExpr(ObjectNameAST); } else { // Otherwise it must be an memory object return ParseMemoryObject(ObjectNameAST); } } ParseMemoryObject(ObjectName ObjectNameAST) { // Check if object name has already been parsed; if not, do so. if (ObjectNameAST == nullptr) ObjectNameAST = ParseObjectName(); auto MemObjectAST = new MemoryObject; MemObjectAST->ObjectName = ObjectNameAST; // Check for array indexing if (TokenType() == '[') MemObjectAST->ArrayIndexing = ParseArrayIndexing(); // Check for assignment (:=, +=, -=, etc.) if (IsTokenAssignmentOperator()) MemObjectAST->AssignStatement = ParseAssigStatement(); return MemObjectAST; } ParseCallExpr(ObjectName ObjectNameAST) { // Check if object name has already been parsed; if not, do so. if (ObjectNameAST == nullptr) ObjectNameAST = ParseObjectName(); auto CallExprAST = new CallExpression; CallExprAST->FunctionName = ObjectNameAST; Accept('('); { CallExprAST->ArgList = ParseArgumentList(); } Accept(')'); return CallExprAST; } ParseObjectName() { auto ObjectNameAST = new ObjectName; ObjectNameAST->IdentifierList.push_back(ParseIdentifier()); // Parse further optional identifiers (separated by a '.' character). while (TokenType() == '.') { AcceptIt(); ObjectNameAST->IdentifierList.push_back(ParseIdentifier()); } return ObjectNameAST; } ParseIdentifier() { auto IdentifierToken = Accept(Types::Identifier); return new Identifier(IdentifierToken); } ParseArithmeticLiteral() { switch (TokenType()) { case IntLiteral: auto CurrToken = AcceptIt(); return new IntLiteral(CurrToken); case FloatLiteral: auto CurrToken = AcceptIt(); return new FloatLiteral(CurrToken); } ErrorUnexpectedToken("Expected arithmetic literal") } |
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int a := 7 + 3 * 2 - 5 * (6 + 3) - 4 |
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; D:\SoftwareEntwicklung\C++\HLC\Tools\XieXie-Compiler\trunk\examples\Tests/ExpressionTest1.xx.asm ; XieXie generated source file ; Fri Dec 27 21:14:14 2013 ; Variable initialization "a" push 7 push 3 push 2 pop ebx pop eax mul eax, ebx push eax push 5 push 6 push 3 pop ebx pop eax add eax, ebx push eax pop ebx pop eax mul eax, ebx push eax pop ebx pop eax sub eax, ebx push eax push 4 pop ebx pop eax sub eax, ebx push eax pop ebx pop eax add eax, ebx push eax ; =============== |
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