60 lines
1.8 KiB
Java
60 lines
1.8 KiB
Java
package frontend.ast.exp;
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import frontend.ast.Node;
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import frontend.ast.SyntaxType;
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import frontend.ast.token.TokenNode;
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import frontend.lexer.TokenStream;
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import frontend.lexer.TokenType;
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import midend.symbol.SymbolManager;
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import midend.symbol.Symbol;
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import midend.symbol.ArraySymbol;
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import error.Errors;
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import error.Error;
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import error.ErrorType;
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public class LVal extends Node {
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public LVal(TokenStream ts) {
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super(SyntaxType.LVAL_EXP, ts);
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}
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public void parse(Errors errors) {
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addChild(new TokenNode(this.ts)); // idenfr
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if (getCurrToken().getType() == TokenType.LBRACK) {
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addChild(new TokenNode(this.ts)); // lbrack
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Exp exp = new Exp(this.ts);
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exp.parse(errors);
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addChild(exp);
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if (getCurrToken().getType() == TokenType.RBRACK) {
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addChild(new TokenNode(this.ts)); // rbrack
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} else {
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errors.addError(new Error(this.ts.peek(-1).getLine(), ErrorType.k));
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}
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}
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}
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public int getType() {
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if (getChildren().size() == 1) {
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TokenNode idenfr = (TokenNode) getChild(0);
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Symbol symbol = SymbolManager.getSymbol(idenfr.getName());
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if (symbol instanceof ArraySymbol) {
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return 1;
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}
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return 0;
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} else {
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return 0;
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}
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}
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public int getValue() {
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TokenNode idenfr = (TokenNode) getChild(0); //idenfr一定是个常量，可在符号表找到且有值
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if (getChildren().size() == 1) {
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Symbol symbol = SymbolManager.getSymbol(idenfr.getName());
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return symbol.getValue(0);
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} else {
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int index = ((Exp) getChild(2)).getValue();
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Symbol symbol = SymbolManager.getSymbol(idenfr.getName());
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return symbol.getValue(index);
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}
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}
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}
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