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negative numbers parsing

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This commit is contained in:
Timerix22 2023-12-22 20:33:25 +06:00
parent cc6cda554c
commit 5a4b2ce3f6
1 changed files with 18 additions and 6 deletions
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24
src/Parser.fu
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@ -3,9 +3,11 @@ class Parser
List<Token()> TokenStorage;
IExpression# RootExpression;
TokenLinkedList() TokensInRPN;
Token() TokZero;
internal Parser(){
RootExpression = new NumericExpression { N = Math.NaN };
TokZero = Token.Create("0", 0, 1, Token.Type_Number);
}
internal IExpression# Parse!(){
@ -22,9 +24,13 @@ class Parser
// Implementation of https://en.wikipedia.org/wiki/Shunting_yard_algorithm
void SortTokensInRPN!(){
Stack<Token>() RPNStack;
// is needed for negative numbers recognition
int prevTokType = Token.Type_BracketOpen;
for(int i = 0; i < TokenStorage.Count; i++){
Token tok = TokenStorage[i];
int type = tok.GetType();
switch(type){
case Token.Type_Number:
TokensInRPN.AddToEnd(tok);
@ -35,6 +41,8 @@ class Parser
case Token.Type_OperatorMod:
case Token.Type_OperatorAdd:
case Token.Type_OperatorSub:
if(type == Token.Type_OperatorSub && prevTokType == Token.Type_BracketOpen)
TokensInRPN.AddToEnd(TokZero);
while(RPNStack.Count != 0 && RPNStack.Peek().GetType() >= type){
Token op2 = RPNStack.Pop();
TokensInRPN.AddToEnd(op2);
@ -47,9 +55,8 @@ class Parser
case Token.Type_BracketClose:
while(RPNStack.Count != 0){
Token op2 = RPNStack.Pop();
if(op2.GetType() == Token.Type_BracketOpen){
if(op2.GetType() == Token.Type_BracketOpen)
break;
}
TokensInRPN.AddToEnd(op2);
}
break;
@ -60,6 +67,8 @@ class Parser
ThrowError("unexpected token type");
break;
}
prevTokType = type;
}
// add remaining operators
@ -76,8 +85,9 @@ class Parser
TokenLinkedListNode? tokenNode = TokensInRPN.GetFirstNode();
while(tokenNode != null){
Token tok = tokenNode.GetValue();
int type = tok.GetType();
switch(tok.GetType()){
switch(type){
case Token.Type_Number:
expressionStack.Push(new NumericExpression { N = StringToDouble(tok.GetStr()) });
break;
@ -100,14 +110,16 @@ class Parser
PushOperatorExpression(expressionStack, tok, new OperatorExpressionSub());
break;
case Token.Type_BracketClose:
ThrowError("unexpected (");
break;
case Token.Type_BracketOpen:
ThrowError("brackets should be handled at SortTokensInRPN");
ThrowError("unexpected )");
break;
case Token.Type_Literal:
ThrowError("not implemented");
break;
default:
ThrowError("unexpected token type");
ThrowError($"unexpected token type: {type}");
break;
}
@ -139,7 +151,7 @@ class Parser
void PushOperatorExpression(Stack<IExpression#>! expressionStack, Token tok, OperatorExpression# opExpr) {
if(expressionStack.Count < 2){
ThrowError("input error: unexpected operator "+tok.GetStr());
ThrowError($"unexpected operator: {tok.GetStr()}");
return;
}
IExpression b = expressionStack.Pop();