Initial commit

jlox/src/main/java/com/craftinginterpreters/lox/Lox.java

@@ -0,0 +1,64 @@
+package com.craftinginterpreters.lox;
+
+import java.io.BufferedReader;
+import java.io.IOException;
+import java.io.InputStreamReader;
+import java.nio.charset.Charset;
+import java.nio.file.Files;
+import java.nio.file.Paths;
+import java.util.List;
+
+public class Lox {
+    static boolean hadError = false;
+
+    public static void main(String[] args) throws IOException {
+        if (args.length > 1) {
+            System.out.println("Usage: jlox [script]");
+            System.exit(64);
+        } else if (args.length == 1) {
+            runFile(args[0]);
+        } else {
+            runPrompt();
+        }
+    }
+
+    private static void runFile(String path) throws IOException {
+        byte[] bytes = Files.readAllBytes(Paths.get(path));
+        run(new String(bytes, Charset.defaultCharset()));
+
+        if (hadError) {
+            System.exit(65);
+        }
+    }
+
+    private static void runPrompt() throws IOException {
+        InputStreamReader input = new InputStreamReader(System.in);
+        BufferedReader reader = new BufferedReader(input);
+
+        for (;;) {
+            System.out.println("> ");
+            String line = reader.readLine();
+            if (line == null) break;
+            run(line);
+            hadError = false;
+        }
+    }
+
+    private static void run(String source) {
+        Scanner scanner = new Scanner(source);
+        List<Token> tokens = scanner.scanTokens();
+
+        for (Token token : tokens) {
+            System.out.println(token);
+        }
+    }
+
+    static void error(int line, String message) {
+        report(line, "", message);
+    }
+
+    private static void report(int line, String where, String message) {
+        System.err.println("[line " + line + "] Error" + where + ": " + message););
+        hadError = true;
+    }
+}

jlox/src/main/java/com/craftinginterpreters/lox/Scanner.java

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+package com.craftinginterpreters.lox;
+
+import java.util.ArrayList;
+import java.util.List;
+
+class Scanner {
+    private final String source;
+    private final List<Token> tokens = new ArrayList<>();
+    private int start = 0;
+    private int current = 0;
+    private int line = 1;
+
+    public Scanner(String source) {
+        this.source = source;
+    }
+
+    List<Token> scanTokens() {
+        while (!isAtEnd()) {
+            start = current;
+            scanToken();
+        }
+
+        tokens.add(new Token(TokenType.EOF, "", null, line));
+        return tokens;
+    }
+
+    private void scanToken() {
+        char c = advance();
+        switch (c) {
+            case '(': addToken(TokenType.LEFT_PAREN); break;
+            case ')': addToken(TokenType.RIGHT_PAREN); break;
+            case '{': addToken(TokenType.LEFT_BRACE); break;
+            case '}': addToken(TokenType.RIGHT_BRACE); break;
+            case ',': addToken(TokenType.COMMA); break;
+            case '.': addToken(TokenType.DOT); break;
+            case '-': addToken(TokenType.MINUS); break;
+            case '+': addToken(TokenType.PLUS); break;
+            case ';': addToken(TokenType.SEMICOLON); break;
+            case '*': addToken(TokenType.STAR); break; 
+        }
+    }
+
+    private boolean isAtEnd() {
+        return current >= source.length();
+    }
+
+    private char advance() {
+        return source.charAt(current++);
+    }
+
+    private void addToken(TokenType type) {
+        addToken(type, null);
+    }
+}

jlox/src/main/java/com/craftinginterpreters/lox/Token.java

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+package com.craftinginterpreters.lox;
+
+class Token {
+    final TokenType type;
+    final String lexeme;
+    final Object literal;
+    final int line;
+
+    public Token(TokenType type, String lexeme, Object literal, int line) {
+        this.type = type;
+        this.lexeme = lexeme;
+        this.literal = literal;
+        this.line = line;
+    }
+
+    @Override
+    public String toString() {
+        return "Token [type=" + type + ", lexeme=" + lexeme + ", literal=" + literal + "]";
+    }
+}

jlox/src/main/java/com/craftinginterpreters/lox/TokenType.java

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+package com.craftinginterpreters.lox;
+
+enum TokenType {
+  // Single-character tokens.
+  LEFT_PAREN, RIGHT_PAREN, LEFT_BRACE, RIGHT_BRACE,
+  COMMA, DOT, MINUS, PLUS, SEMICOLON, SLASH, STAR,
+
+  // One or two character tokens.
+  BANG, BANG_EQUAL,
+  EQUAL, EQUAL_EQUAL,
+  GREATER, GREATER_EQUAL,
+  LESS, LESS_EQUAL,
+
+  // Literals.
+  IDENTIFIER, STRING, NUMBER,
+
+  // Keywords.
+  AND, CLASS, ELSE, FALSE, FUN, FOR, IF, NIL, OR,
+  PRINT, RETURN, SUPER, THIS, TRUE, VAR, WHILE,
+
+  EOF
+}

jlox/src/test/java/com/craftinginterpreters/lox/AppTest.java

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+package com.craftinginterpreters.lox;
+
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+import org.junit.jupiter.api.Test;
+
+/**
+ * Unit test for simple App.
+ */
+public class AppTest {
+
+    /**
+     * Rigorous Test :-)
+     */
+    @Test
+    public void shouldAnswerWithTrue() {
+        assertTrue(true);
+    }
+}