Created
November 16, 2022 18:23
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Interface y records para evaluar expresiones
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// Expresiones | |
// sealed interface y permits en records. | |
// Los records son buenos candidatos para usarlos en permits porque son final. | |
//package com.example.evaluar; | |
sealed interface Expr | |
//permits ConstantExpr, PlusExpr, TimesExpr, NegExpr, MinusExpr, DivideExpr | |
{ | |
int eval(); | |
} | |
record MinusExpr(Expr a, Expr b) implements Expr { | |
public int eval() { return a.eval() - b.eval(); } | |
} | |
record DivideExpr(Expr a, Expr b) implements Expr { | |
public int eval() { return a.eval() / b.eval(); } | |
} | |
record ConstantExpr(int i) implements Expr { | |
/** | |
* Constructor que recibe una cadena en vez de un entero. | |
* @param i El valor de tipo cadena a convertir en entero. | |
*/ | |
ConstantExpr(String i){ | |
this(Integer.parseInt(i)); | |
} | |
public int eval() { return i(); } | |
} | |
record PlusExpr(Expr a, Expr b) implements Expr { | |
public int eval() { return a.eval() + b.eval(); } | |
} | |
record TimesExpr(Expr a, Expr b) implements Expr { | |
public int eval() { return a.eval() * b.eval(); } | |
} | |
record NegExpr(Expr e) implements Expr { | |
public int eval() { return -e.eval(); } | |
} |
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