[tlox] Initial Expression parsing and evaluation

jlox/tlox/src/main/java/xyz/ctsk/lox/Main.java

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+package xyz.ctsk.lox;
+
+import com.oracle.truffle.api.Truffle;
+import xyz.ctsk.lox.nodes.LoxRootNode;
+import xyz.ctsk.lox.parser.LoxParser;
+
+import java.io.BufferedReader;
+import java.io.IOException;
+import java.io.InputStreamReader;
+
+public class Main {
+
+    public static void repl() throws IOException {
+        var input = new InputStreamReader(System.in);
+        var reader = new BufferedReader(input);
+
+        while (true) {
+            System.out.print(" >> ");
+            var line = reader.readLine();
+            if (line == null) break;
+            run(line);
+        }
+    }
+
+    public static void run(String program) {
+        var parsed = LoxParser.parseLox(program);
+
+        if (parsed instanceof LoxParser.ExpressionContext expr) {
+            var root = new LoxRootNode(expr.result);
+            var callTarget = root.getCallTarget();
+            System.out.println(callTarget.call());
+        }
+    }
+
+    public static void main(String[] args) throws IOException {
+        repl();
+    }
+}

jlox/tlox/src/main/java/xyz/ctsk/lox/nodes/LoxExpressionNode.java

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+package xyz.ctsk.lox.nodes;
+
+import com.oracle.truffle.api.frame.VirtualFrame;
+
+public abstract class LoxExpressionNode extends LoxNode {
+    public abstract double executeDouble(VirtualFrame frame);
+}

jlox/tlox/src/main/java/xyz/ctsk/lox/nodes/LoxNode.java

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+package xyz.ctsk.lox.nodes;
+
+import com.oracle.truffle.api.nodes.Node;
+
+public class LoxNode extends Node {
+}

jlox/tlox/src/main/java/xyz/ctsk/lox/nodes/LoxRootNode.java

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+package xyz.ctsk.lox.nodes;
+
+import com.oracle.truffle.api.frame.VirtualFrame;
+import com.oracle.truffle.api.nodes.RootNode;
+
+public class LoxRootNode extends RootNode {
+    @SuppressWarnings("FieldMayBeFinal")
+    @Child
+    private LoxExpressionNode exprNode;
+
+    public LoxRootNode(LoxExpressionNode exprNode) {
+        super(null);
+        this.exprNode = exprNode;
+    }
+
+    @Override
+    public Object execute(VirtualFrame frame) {
+        return this.exprNode.executeDouble(frame);
+    }
+}

jlox/tlox/src/main/java/xyz/ctsk/lox/nodes/expr/LoxAddNode.java

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+package xyz.ctsk.lox.nodes.expr;
+
+import com.oracle.truffle.api.frame.VirtualFrame;
+import com.oracle.truffle.api.nodes.Node;
+import xyz.ctsk.lox.nodes.LoxExpressionNode;
+
+public class LoxAddNode extends LoxExpressionNode {
+    @SuppressWarnings("FieldMayBeFinal")
+    @Node.Child
+    private LoxExpressionNode leftNode, rightNode;
+
+    public LoxAddNode(LoxExpressionNode leftNode, LoxExpressionNode rightNode) {
+        this.leftNode = leftNode;
+        this.rightNode = rightNode;
+    }
+
+
+    @Override
+    public double executeDouble(VirtualFrame frame) {
+        var leftValue = leftNode.executeDouble(frame);
+        var rightValue = rightNode.executeDouble(frame);
+        return leftValue + rightValue;
+    }
+}

jlox/tlox/src/main/java/xyz/ctsk/lox/nodes/expr/LoxDivNode.java

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+package xyz.ctsk.lox.nodes.expr;
+
+import com.oracle.truffle.api.frame.VirtualFrame;
+import xyz.ctsk.lox.nodes.LoxExpressionNode;
+
+public class LoxDivNode extends LoxExpressionNode {
+    @SuppressWarnings("FieldMayBeFinal")
+    @Child
+    private LoxExpressionNode leftNode, rightNode;
+
+    public LoxDivNode(LoxExpressionNode leftNode, LoxExpressionNode rightNode) {
+        this.leftNode = leftNode;
+        this.rightNode = rightNode;
+    }
+
+    @Override
+    public double executeDouble(VirtualFrame frame) {
+        var leftValue = leftNode.executeDouble(frame);
+        var rightValue = rightNode.executeDouble(frame);
+        return leftValue / rightValue;
+    }
+}

jlox/tlox/src/main/java/xyz/ctsk/lox/nodes/expr/LoxMulNode.java

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+package xyz.ctsk.lox.nodes.expr;
+
+import com.oracle.truffle.api.frame.VirtualFrame;
+import xyz.ctsk.lox.nodes.LoxExpressionNode;
+
+public class LoxMulNode extends LoxExpressionNode {
+    @SuppressWarnings("FieldMayBeFinal")
+    @Child
+    private LoxExpressionNode leftNode, rightNode;
+
+    public LoxMulNode(LoxExpressionNode leftNode, LoxExpressionNode rightNode) {
+        this.leftNode = leftNode;
+        this.rightNode = rightNode;
+    }
+
+    @Override
+    public double executeDouble(VirtualFrame frame) {
+        var leftValue = leftNode.executeDouble(frame);
+        var rightValue = rightNode.executeDouble(frame);
+        return leftValue * rightValue;
+    }
+}

jlox/tlox/src/main/java/xyz/ctsk/lox/nodes/expr/LoxNumberLiteralNode.java

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+package xyz.ctsk.lox.nodes.expr;
+
+import com.oracle.truffle.api.frame.VirtualFrame;
+import xyz.ctsk.lox.nodes.LoxExpressionNode;
+
+public class LoxNumberLiteralNode extends LoxExpressionNode {
+    private final double value;
+
+    public LoxNumberLiteralNode(double value) {
+        this.value = value;
+    }
+
+    public double executeDouble(VirtualFrame frame) {
+        return this.value;
+    }
+}

jlox/tlox/src/main/java/xyz/ctsk/lox/nodes/expr/LoxSubNode.java

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+package xyz.ctsk.lox.nodes.expr;
+
+import com.oracle.truffle.api.frame.VirtualFrame;
+import xyz.ctsk.lox.nodes.LoxExpressionNode;
+
+public class LoxSubNode extends LoxExpressionNode {
+    @SuppressWarnings("FieldMayBeFinal")
+    @Child
+    private LoxExpressionNode leftNode, rightNode;
+
+    public LoxSubNode(LoxExpressionNode leftNode, LoxExpressionNode rightNode) {
+        this.leftNode = leftNode;
+        this.rightNode = rightNode;
+    }
+
+    @Override
+    public double executeDouble(VirtualFrame frame) {
+        var leftValue = leftNode.executeDouble(frame);
+        var rightValue = rightNode.executeDouble(frame);
+        return leftValue - rightValue;
+    }
+}

jlox/tlox/src/main/java/xyz/ctsk/lox/parser/LoxNodeFactory.java

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+package xyz.ctsk.lox.parser;
+
+import org.antlr.v4.runtime.Token;
+import xyz.ctsk.lox.nodes.LoxExpressionNode;
+import xyz.ctsk.lox.nodes.expr.*;
+
+public class LoxNodeFactory {
+    public static LoxNumberLiteralNode createNumberLiteral(Token literalToken) {
+        var value = Double.parseDouble(literalToken.getText());
+        return new LoxNumberLiteralNode(value);
+    }
+
+    public static LoxExpressionNode createBinaryNode(Token op, LoxExpressionNode left, LoxExpressionNode right) {
+        return switch (op.getText()) {
+            case "+" -> new LoxAddNode(left, right);
+            case "-" -> new LoxSubNode(left, right);
+            case "*" -> new LoxMulNode(left, right);
+            case "/" -> new LoxDivNode(left, right);
+            default -> null;
+        };
+    }
+}

jlox/tlox/src/main/resources/xyz/ctsk/lox/parser/Lox.g4

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+grammar Lox;
+
+
+@parser::header {
+
+import com.oracle.truffle.api.source.Source;
+
+import xyz.ctsk.lox.nodes.LoxExpressionNode;
+import xyz.ctsk.lox.parser.*;
+
+}
+
+@parser::members {
+    private LoxNodeFactory factory;
+
+    public static Object parseLox(String source) {
+        LoxLexer lexer = new LoxLexer(CharStreams.fromString(source));
+        LoxParser parser = new LoxParser(new CommonTokenStream(lexer));
+
+        parser.factory = new LoxNodeFactory();
+
+        return parser.expression();
+    }
+}
+
+file returns [LoxExpressionNode result]
+    : expression EOF { $result = $expression.result; }
+    ;
+
+expression returns [LoxExpressionNode result]
+    : literal                                 { $result = $literal.result; }
+    | left=expression op=( '*' | '/' ) right=expression { $result = factory.createBinaryNode($op, $left.result, $right.result); }
+    | left=expression op=( '+' | '-' ) right=expression { $result = factory.createBinaryNode($op, $left.result, $right.result); }
+    ;
+
+literal returns [LoxExpressionNode result]
+    : NUMBER { $result = factory.createNumberLiteral($NUMBER); }
+    ;
+
+AND: 'and' ;
+CLASS: 'class' ;
+ELSE: 'else' ;
+FALSE: 'false' ;
+FOR: 'for' ;
+FUN: 'fun' ;
+IF: 'if' ;
+NIL: 'nil' ;
+OR: 'or' ;
+PRINT: 'print' ;
+RETURN: 'return' ;
+SUPER: 'super' ;
+THIS: 'this' ;
+TRUE: 'true' ;
+VAR: 'var' ;
+WHILE: 'while';
+
+LESS: '<' ;
+LESS_EQUAL: '<=';
+GREATER: '>' ;
+GREATER_EQUAL: '>=' ;
+BANG: '!' ;
+BANG_EQUAL: '!=' ;
+EQUAL: '=' ;
+EQUAL_EQUAL: '==' ;
+
+NUMBER
+    : DIGIT+ ('.' DIGIT+)?
+    ;
+
+STRING
+    : '"' ~["]* '"'
+    ;
+
+IDENTIFIER
+    : LETTER ( LETTER | DIGIT | UNDERSCORE )*
+    ;
+
+fragment LETTER
+    : [a-zA-Z]
+    ;
+
+fragment DIGIT
+    : [0-9]
+    ;
+
+fragment UNDERSCORE
+    : '_'
+    ;
+
+WS
+    : [ \t\r\n]+ -> skip
+    ;