From 68a2ebd34fc94488e89ffb82b359ec6e7e152ae9 Mon Sep 17 00:00:00 2001
From: Tom Willemse
Date: Thu, 8 Jul 2021 00:14:31 -0700
Subject: Restructure project to make room for clox

---
 .../com/craftinginterpreters/tool/GenerateAst.java | 100 +++++++++++++++++++++
 1 file changed, 100 insertions(+)
 create mode 100644 jlox/src/com/craftinginterpreters/tool/GenerateAst.java

(limited to 'jlox/src/com/craftinginterpreters/tool/GenerateAst.java')

diff --git a/jlox/src/com/craftinginterpreters/tool/GenerateAst.java b/jlox/src/com/craftinginterpreters/tool/GenerateAst.java
new file mode 100644
index 0000000..04b4500
--- /dev/null
+++ b/jlox/src/com/craftinginterpreters/tool/GenerateAst.java
@@ -0,0 +1,100 @@
+package com.craftinginterpreters.tool;
+
+import java.io.IOException;
+import java.io.PrintWriter;
+import java.util.Arrays;
+import java.util.List;
+
+public class GenerateAst {
+    public static void main(String[] args) throws IOException {
+        if (args.length != 1) {
+            System.err.println("Usage: generate_ast <output directory>");
+            System.exit(64);
+        }
+
+        String outputDir = args[0];
+
+        defineAst(outputDir, "Expr",
+                Arrays.asList("Assign : Token name, Expr value", "Binary : Expr left, Token operator, Expr right",
+                        "Call : Expr callee, Token paren, List<Expr> arguments", "Get : Expr object, Token name",
+                        "Grouping : Expr expression", "Literal : Object value",
+                        "Logical : Expr left, Token operator, Expr right", "Set : Expr object, Token name, Expr value",
+                        "Super : Token keyword, Token method", "This : Token keyword",
+                        "Unary : Token operator, Expr right", "Variable : Token name"));
+        defineAst(outputDir, "Stmt",
+                Arrays.asList("Block : List<Stmt> statements",
+                        "Class : Token name, Expr.Variable superclass, List<Stmt.Function> methods",
+                        "Expression : Expr expression", "Function : Token name, List<Token> params, List<Stmt> body",
+                        "If : Expr condition, Stmt thenBranch, Stmt elseBranch", "Print : Expr expression",
+                        "Return : Token keyword, Expr value", "Var : Token name, Expr initializer",
+                        "While : Expr condition, Stmt body"));
+    }
+
+    private static void defineAst(String outputDir, String baseName, List<String> types) throws IOException {
+        String path = outputDir + "/" + baseName + ".java";
+        PrintWriter writer = new PrintWriter(path);
+
+        writer.println("package com.craftinginterpreters.lox;");
+        writer.println();
+        writer.println("import java.util.List;");
+        writer.println();
+        writer.println("abstract class " + baseName + " {");
+
+        defineVisitor(writer, baseName, types);
+
+        for (String type : types) {
+            String className = type.split(":")[0].trim();
+            String fields = type.split(":")[1].trim();
+            defineType(writer, baseName, className, fields);
+        }
+
+        // The base accept() method
+        writer.println();
+        writer.println("  abstract <R> R accept(Visitor<R> visitor);");
+
+        writer.println("}");
+        writer.close();
+    }
+
+    private static void defineVisitor(PrintWriter writer, String baseName, List<String> types) {
+        writer.println("  interface Visitor<R> {");
+
+        for (String type : types) {
+            String typeName = type.split(":")[0].trim();
+            writer.println("    R visit" + typeName + baseName + "(" + typeName + " " + baseName.toLowerCase() + ");");
+        }
+
+        writer.println("  }");
+    }
+
+    private static void defineType(PrintWriter writer, String baseName, String className, String fieldList) {
+        writer.println("  static class " + className + " extends " + baseName + " {");
+
+        // Constructor
+        writer.println("    " + className + "(" + fieldList + ") {");
+
+        // Store parameters in fields.
+        String[] fields = fieldList.split(", ");
+        for (String field : fields) {
+            String name = field.split(" ")[1];
+            writer.println("      this." + name + " = " + name + ";");
+        }
+
+        writer.println("    }");
+
+        // Visitor pattern.
+        writer.println();
+        writer.println("    @Override");
+        writer.println("    <R> R accept(Visitor<R> visitor) {");
+        writer.println("      return visitor.visit" + className + baseName + "(this);");
+        writer.println("    }");
+
+        // Fields
+        writer.println();
+        for (String field : fields) {
+            writer.println("    final " + field + ";");
+        }
+
+        writer.println("  }");
+    }
+}
-- 
cgit v1.2.3-54-g00ecf