Eksami põhiosa harjutuse lahendus

Author: sim642

sols/proovieksam/Estolog.g4

@@ -0,0 +1,35 @@
+grammar Estolog;
+@header { package proovieksam; }
+
+// Seda reeglit pole vaja muuta
+init : prog EOF;
+
+// Seda reeglit tuleb muuta / täiendada
+// (Ilmselt soovid ka defineerida uusi abireegleid)
+prog
+    : (def ';')* avaldis
+    ;
+
+def
+    : Muutuja ':=' avaldis
+    ;
+
+avaldis
+    : avaldis 'JA' avaldis                              # BinOp
+    | avaldis 'VOI' avaldis                             # BinOp
+    | avaldis 'NING' avaldis                            # BinOp
+    | 'KUI' avaldis 'SIIS' avaldis ('MUIDU' avaldis)?   # KuiSiis
+    | lihtneAvaldis '=' lihtneAvaldis                   # BinOp
+    | lihtneAvaldis                                     # Lihtne
+    ;
+
+lihtneAvaldis
+    : Muutuja                                           # Muutuja
+    | Arv                                               # Literaal
+    | '(' avaldis ')'                                   # Sulud
+    ;
+
+Muutuja : [a-zA-Z]+;
+Arv : [01];
+
+WS : [ \r\n\t] -> skip;

sols/proovieksam/EstologAst.java

@@ -0,0 +1,112 @@
+package proovieksam;
+
+import org.antlr.v4.runtime.BailErrorStrategy;
+import org.antlr.v4.runtime.CharStreams;
+import org.antlr.v4.runtime.CommonTokenStream;
+import org.antlr.v4.runtime.tree.ParseTree;
+import proovieksam.ast.EstologDef;
+import proovieksam.ast.EstologNode;
+import utils.ExceptionErrorListener;
+
+import java.io.IOException;
+import java.nio.file.Paths;
+import java.util.ArrayList;
+import java.util.List;
+
+import static proovieksam.EstologParser.*;
+import static proovieksam.ast.EstologNode.*;
+
+public class EstologAst {
+
+    static void main() throws IOException {
+        EstologNode ast = makeEstologAst("""
+                x := 0;
+                y := 1;
+                a := (x JA y);
+                b := (x VOI y);
+
+                (KUI (x = y) SIIS a MUIDU b)""");
+        System.out.println(ast);
+        ast.renderPngFile(Paths.get("graphs", "estolog.png"));
+    }
+
+    public static EstologNode makeEstologAst(String input) {
+        EstologLexer lexer = new EstologLexer(CharStreams.fromString(input));
+        lexer.removeErrorListeners();
+        lexer.addErrorListener(new ExceptionErrorListener());
+
+        EstologParser parser = new EstologParser(new CommonTokenStream(lexer));
+        parser.removeErrorListeners();
+        parser.setErrorHandler(new BailErrorStrategy());
+
+        ParseTree tree = parser.init();
+        //System.out.println(tree.toStringTree(parser));
+        return parseTreeToAst(tree);
+    }
+
+    // Implementeeri see meetod.
+    private static EstologNode parseTreeToAst(ParseTree tree) {
+        EstologBaseVisitor<EstologNode> visitor = new EstologBaseVisitor<>() {
+            @Override
+            public EstologNode visitInit(InitContext ctx) {
+                return visit(ctx.prog());
+            }
+
+            @Override
+            public EstologNode visitProg(ProgContext ctx) {
+                List<EstologDef> defs = new ArrayList<>();
+                for (DefContext defContext : ctx.def()) {
+                    defs.add(visitDef(defContext)); // otse õige visit kutse
+                }
+                EstologNode avaldis = visit(ctx.avaldis());
+                return prog(avaldis, defs);
+            }
+
+            @Override
+            public EstologDef visitDef(DefContext ctx) {
+                // täpsustatud tagastustüüp
+                return def(ctx.Muutuja().getText(), visit(ctx.avaldis()));
+            }
+
+            @Override
+            public EstologNode visitLiteraal(LiteraalContext ctx) {
+                return lit(ctx.getText().equals("1"));
+            }
+
+            @Override
+            public EstologNode visitMuutuja(MuutujaContext ctx) {
+                return var(ctx.getText());
+            }
+
+            @Override
+            public EstologNode visitSulud(SuludContext ctx) {
+                return visit(ctx.avaldis());
+            }
+
+            @Override
+            public EstologNode visitBinOp(BinOpContext ctx) {
+                EstologNode left = visit(ctx.getChild(0));
+                EstologNode right = visit(ctx.getChild(2));
+                return switch (ctx.getChild(1).getText()) {
+                    case "=" -> vordus(left, right);
+                    case "VOI" -> voi(left, right);
+                    case "JA", "NING" -> ja(left, right);
+                    default -> throw new UnsupportedOperationException();
+                };
+            }
+
+            @Override
+            public EstologNode visitKuiSiis(KuiSiisContext ctx) {
+                EstologNode kui = visit(ctx.avaldis(0));
+                EstologNode siis = visit(ctx.avaldis(1));
+                EstologNode muidu = null;
+                if (ctx.avaldis(2) != null) muidu = visit(ctx.avaldis(2));
+                return kui(kui, siis, muidu);
+            }
+
+            // Lihtne käsitletakse BaseVisitor-is vaikimisi
+        };
+
+        return visitor.visit(tree);
+    }
+}