feat: 语法树的访问者和类型检测访问者 (#56)

Reviewed-on: PostGuard/Canon#56

Canon.Generator/Extensions/RootCommandExtension.cs

@@ -5,9 +5,9 @@ namespace Canon.Generator.Extensions;
 
 public static class RootCommandExtension
 {
-    public static void AddGenerateCommand(this RootCommand rootCommand)
+    public static void AddGrammarCommand(this RootCommand rootCommand)
     {
-        Command generateCommand = new("generate", "Generate source files.");
+        Command generateCommand = new("grammar", "Generate grammar parser source files.");
 
         Argument<string> filenameArgument = new(name: "filename",
             description: "determines the generated file name.",
@@ -37,4 +37,16 @@ public static class RootCommandExtension
 
         rootCommand.AddCommand(generateCommand);
     }
+
+    public static void AddSyntaxVisitorCommand(this RootCommand rootCommand)
+    {
+        Command syntaxCommand = new("syntax", "Generate syntax visitor source code.");
+
+        syntaxCommand.SetHandler(async () =>
+        {
+            await SyntaxVisitorGenerator.SyntaxVisitorGenerator.Generate();
+        });
+
+        rootCommand.AddCommand(syntaxCommand);
+    }
 }

Canon.Generator/Program.cs

@@ -3,6 +3,7 @@ using Canon.Generator.Extensions;
 
 RootCommand rootCommand = new("Canon Compiler Source Generator");
 
-rootCommand.AddGenerateCommand();
+rootCommand.AddGrammarCommand();
+rootCommand.AddSyntaxVisitorCommand();
 
 await rootCommand.InvokeAsync(args);

Canon.Generator/SyntaxVisitorGenerator/SyntaxVisitorGenerator.cs

@@ -0,0 +1,78 @@
+using System.Text;
+
+namespace Canon.Generator.SyntaxVisitorGenerator;
+
+public static class SyntaxVisitorGenerator
+{
+    private static readonly List<string> s_nodes =
+    [
+        "AddOperator",
+        "BasicType",
+        "CompoundStatement",
+        "ConstDeclaration",
+        "ConstDeclarations",
+        "ConstValue",
+        "ElsePart",
+        "Expression",
+        "ExpressionList",
+        "Factor",
+        "FormalParameter",
+        "IdentifierList",
+        "IdentifierVarPart",
+        "MultiplyOperator",
+        "Parameter",
+        "ParameterList",
+        "Period",
+        "ProcedureCall",
+        "ProgramBody",
+        "ProgramHead",
+        "ProgramStruct",
+        "RelationOperator",
+        "SimpleExpression",
+        "Statement",
+        "StatementList",
+        "Subprogram",
+        "SubprogramBody",
+        "SubprogramDeclarations",
+        "SubprogramHead",
+        "Term",
+        "TypeSyntaxNode",
+        "ValueParameter",
+        "VarDeclaration",
+        "VarDeclarations",
+        "Variable",
+        "VarParameter"
+    ];
+
+    public static async Task Generate()
+    {
+        FileInfo output = new(Path.Combine(Environment.CurrentDirectory, "SyntaxNodeVisitor.cs"));
+
+        StringBuilder builder = new();
+
+        builder.Append("using Canon.Core.SyntaxNodes;\n").Append('\n');
+        builder.Append("namespace Canon.Core.Abstractions;\n").Append('\n');
+
+        builder.Append("public abstract class SyntaxNodeVisitor\n").Append("{\n");
+
+        foreach (string node in s_nodes)
+        {
+            string nodeName = node.Substring(0, 1).ToLower() + node.Substring(1);
+
+            builder.Append($"    public virtual void PreVisit({node} {nodeName})\n")
+                .Append("    {\n")
+                .Append("    }\n")
+                .Append('\n');
+
+            builder.Append($"    public virtual void PostVisit({node} {nodeName})\n")
+                .Append("    {\n")
+                .Append("    }\n")
+                .Append('\n');
+        }
+
+        builder.Append('}');
+
+        await using StreamWriter writer = output.CreateText();
+        await writer.WriteAsync(builder.ToString());
+    }
+}