new parser

Author: h908714124

build.gradle

@@ -8,10 +8,8 @@ group = 'io.github.jbock-java'
 
 compileJava {
     options.encoding = 'UTF-8'
-    sourceCompatibility = '17'
-    targetCompatibility = '17'
-    options.compilerArgs << '--release'
-    options.compilerArgs << '17'
+    sourceCompatibility = '21'
+    targetCompatibility = '21'
 }
 
 jar {

src/main/java/io/polypen/Expressions.java

@@ -1,6 +1,7 @@
 package io.polypen;
 
-import io.polypen.Expressions.Expression;
+import io.polypen.parse.Parser;
+import io.polypen.parse.Parser.ListExpr;
 
 import java.util.Scanner;
 
@@ -13,7 +14,7 @@ public static void main(String[] args) {
             String line = in.nextLine();
             sb.append(line);
         }
-        Expression expression = Parser.parse(sb.toString());
-        System.out.println(expression.eval());
+        ListExpr expression = Parser.parse(sb.toString());
+        System.out.println(Parser.eval(expression));
     }
 }

src/main/java/io/polypen/Main.java

@@ -3,18 +3,31 @@
 import java.util.ArrayList;
 import java.util.List;
 
-public record Monomial(int coefficient, int exponent) {
+public record Monomial(int coefficient, int degree) {
 
     public static final Monomial ZERO = new Monomial(0, 0);
 
+    public static Monomial constant(int n) {
+        return new Monomial(n, 0);
+    }
+
     public Polynomial multiply(Polynomial p) {
-        List<Integer> result = new ArrayList<>(p.degree() + exponent + 1);
-        for (int i = 0; i < exponent; i++) {
+        List<Integer> result = new ArrayList<>(p.degree() + degree + 1);
+        for (int i = 0; i < degree; i++) {
             result.add(0);
         }
         for (int i = 0; i <= p.degree(); i++) {
             result.add(coefficient * (p.coefficient(i)));
         }
         return new Polynomial(result);
     }
+
+    public Polynomial polynomial() {
+        List<Integer> coefficients = new ArrayList<>(degree + 1);
+        for (int i = 0; i < degree; i++) {
+            coefficients.add(0);
+        }
+        coefficients.add(coefficient);
+        return new Polynomial(coefficients);
+    }
 }

src/main/java/io/polypen/Monomial.java

@@ -1,5 +1,7 @@
 package io.polypen;
 
+import io.polypen.parse.Parser;
+
 import java.util.ArrayList;
 import java.util.List;
 
@@ -15,55 +17,7 @@ public final class Polynomial {
     }
 
     public static Polynomial parse(String s) {
-        NestingInfo nestingInfo = unnest(s.trim());
-        return new Polynomial(Parser.parsePolynomial(nestingInfo.term)).multiply(nestingInfo.sign);
-    }
-
-    private static NestingInfo unnest(String s) {
-        int nestingLevel = -1;
-        int sign = 1;
-        int start = 0;
-        int end = 0;
-        for (int i = 0; i < s.length(); i++) {
-            char c = s.charAt(i);
-            switch (c) {
-                case '(' -> {
-                    nestingLevel = Math.max(nestingLevel, 0) + 1;
-                }
-                case ')' -> {
-                    if (end == 0) {
-                        end = i;
-                    }
-                    nestingLevel--;
-                    if (nestingLevel < 0) {
-                        throw new IllegalStateException("Illegal nesting");
-                    }
-                }
-                case '-' -> {
-                    if (start == 0) {
-                        sign *= -1;
-                    }
-                }
-                case '+', ' ' -> {
-                    //ignore
-                }
-                default -> {
-                    if (start == 0) {
-                        start = i;
-                    }
-                }
-            }
-        }
-        if (nestingLevel > 0) {
-            throw new IllegalStateException("Illegal nesting");
-        }
-        if (nestingLevel == -1) {
-            return new NestingInfo(1, s);
-        }
-        return new NestingInfo(sign, s.substring(start, end));
-    }
-
-    private record NestingInfo(int sign, String term) {
+        return Parser.eval(Parser.parse(s));
     }
 
     public Polynomial add(Polynomial other) {

src/main/java/io/polypen/Parser.java

@@ -2,24 +2,21 @@
 
 import io.polypen.parse.Parser.Expr;
 import io.polypen.parse.Parser.ListExpr;
-import io.polypen.parse.Parser.MinusExpr;
 import io.polypen.parse.Parser.MultExpr;
 import io.polypen.parse.Parser.NumberExpr;
-import io.polypen.parse.Parser.PlusExpr;
 import io.polypen.parse.Parser.VarExp;
 
 import java.util.ArrayList;
 import java.util.List;
 
 public class Macro {
 
-    static ListExpr applyStarMacro(ListExpr listExpr) {
+    static List<Expr> applyStarMacro(ListExpr listExpr) {
         List<Expr> exprs = listExpr.value();
         List<Expr> exprsCopy = new ArrayList<>(exprs.size());
         List<Expr> region = new ArrayList<>(exprs.size());
         Expr previous = null;
-        for (int i = 0; i < exprs.size(); i++) {
-            Expr expr = exprs.get(i);
+        for (Expr expr : exprs) {
             if (isStrongBind(previous) && (isStrongBind(expr) || !region.isEmpty())) {
                 region.add(previous);
             } else {
@@ -33,23 +30,28 @@ static ListExpr applyStarMacro(ListExpr listExpr) {
             }
             previous = expr;
         }
+        if (exprsCopy.isEmpty()) {
+            return listExpr.value();
+        }
         if (region.isEmpty()) {
             exprsCopy.add(previous);
         } else {
             region.add(previous);
             exprsCopy.add(new ListExpr(region));
         }
-        return new ListExpr(exprsCopy);
+        return exprsCopy;
     }
 
     public static boolean isStrongBind(Expr expr) {
         if (expr == null) {
             return false;
         }
-        return expr instanceof MultExpr || expr instanceof VarExp || expr instanceof NumberExpr || expr instanceof ListExpr;
-    }
-
-    public static boolean isPlus(Expr expr) {
-        return expr instanceof PlusExpr || expr instanceof MinusExpr;
+        return switch (expr) {
+            case ListExpr ignored -> true;
+            case MultExpr ignored -> true;
+            case NumberExpr ignored -> true;
+            case VarExp ignored -> true;
+            default -> false;
+        };
     }
 }