Add some codegen infrastructure

src/bin/bolt.ts

@@ -14,6 +14,7 @@ import { Checker } from "../checker"
 import { SourceFile, TextFile } from "../cst"
 import { parseSourceFile } from ".."
 import { Analyser } from "../analysis"
+import { Program } from "../program"
 
 function debug(value: any) {
   console.error(util.inspect(value, { colors: true, depth: Infinity }));
@@ -37,18 +38,18 @@ yargs
       const filename = path.resolve(cwd, args.file);
 
       const diagnostics = new ConsoleDiagnostics();
-      const text = fs.readFileSync(filename, 'utf8')
-      const file = new TextFile(filename, text);
-      const sourceFile = parseSourceFile(file, diagnostics);
-      if (sourceFile === null) {
+      const program = new Program([ filename ]);
+      if (program.diagnostics.hasError) {
+        process.exit(1);
+      }
+      program.check();
+      if (program.diagnostics.hasError) {
+        process.exit(1);
+      }
+      program.emit();
+      if (program.diagnostics.hasError) {
         process.exit(1);
       }
-      //debug(sourceFile.toJSON());
-      const analyser = new Analyser();
-      analyser.addSourceFile(sourceFile);
-      const checker = new Checker(analyser, diagnostics);
-      checker.check(sourceFile);
-
     }
   )
   .help()

src/cast.ts

@@ -0,0 +1,379 @@
+
+import type stream from "stream"
+import { IndentWriter } from "./util";
+
+export const enum CNodeKind {
+
+  // Types
+  BuiltinType,
+
+  // Statements
+  ExprStmt,
+  RetStmt,
+
+  // Expressions
+  CallExpr,
+  RefExpr,
+  ConstExpr,
+
+  // Declarations
+  TypeDecl,
+  VarDecl,
+  FuncDecl,
+
+  // Directives
+  IncDir,
+
+  // Other nodes
+  Program,
+
+}
+
+export const enum CBuiltinTypeKind {
+  Char,
+  Short,
+  Int,
+  Long,
+  LongLong,
+  UnsignedChar,
+  UnsignedShort,
+  UnsignedInt,
+  UnsignedLong,
+  UnsignedLongLong,
+}
+
+abstract class CNodeBase {
+  public abstract readonly kind: CNodeKind;
+}
+
+export class CBuiltinType extends CNodeBase {
+
+  public readonly kind = CNodeKind.BuiltinType;
+
+  public constructor(
+    public typeKind: CBuiltinTypeKind,
+  ) {
+    super();
+  }
+
+}
+
+export type CType
+  = CBuiltinType
+
+export class CRefExpr extends CNodeBase {
+
+  public readonly kind = CNodeKind.RefExpr;
+
+  public constructor(
+    public name: string
+  ) {
+    super();
+  }
+
+}
+
+export class CCallExpr extends CNodeBase {
+
+  public readonly kind = CNodeKind.CallExpr;
+
+  public constructor(
+    public operator: CExpr,
+    public args: CExpr[],
+  ) {
+    super();
+  }
+
+}
+
+export class CConstExpr extends CNodeBase {
+
+  public readonly kind = CNodeKind.ConstExpr;
+
+  public constructor(
+    public value: bigint | string | boolean,
+  ) {
+    super();
+  }
+
+}
+
+export type CExpr
+  = CRefExpr
+  | CCallExpr
+  | CConstExpr
+  ;
+
+export class CRetStmt extends CNodeBase {
+
+  public readonly kind = CNodeKind.RetStmt;
+
+  public constructor(
+    public value: CExpr | null,
+  ) {
+    super();
+  }
+
+}
+
+export class CExprStmt extends CNodeBase {
+
+  public readonly kind = CNodeKind.ExprStmt;
+
+  public constructor(
+    public expr: CExpr,
+  ) {
+    super();
+  }
+
+}
+
+export type CStmt
+  = CExprStmt
+  | CRetStmt;
+
+export class CTypeDecl extends CNodeBase {
+
+  public readonly kind = CNodeKind.TypeDecl;
+
+  public constructor(
+    public name: string,
+    public type: CType,
+  ) {
+    super();
+  }
+
+}
+
+export class CFuncDecl extends CNodeBase {
+
+  public readonly kind = CNodeKind.FuncDecl;
+
+  public constructor(
+    public returnType: CType,
+    public name: string,
+    public params: Array<[CType, string]>,
+    public body: CStmt[] | null,
+  ) {
+    super();
+  }
+
+}
+
+export class CVarDecl extends CNodeBase {
+
+  public readonly kind = CNodeKind.VarDecl;
+
+  public constructor(
+    public isExtern: boolean,
+    public type: CType,
+    public name: string,
+  ) {
+    super();
+  }
+
+}
+
+export type CDecl
+  = CTypeDecl
+  | CVarDecl
+  | CFuncDecl
+
+export class CIncDir extends CNodeBase {
+
+  public readonly kind = CNodeKind.IncDir;
+
+  public constructor(
+    public filePath: string,
+    public isSystem = false,
+  ) {
+    super();
+  }
+
+}
+
+export type CDir
+  = CIncDir;
+
+export class CProgram extends CNodeBase {
+
+  public readonly kind = CNodeKind.Program;
+
+  public constructor(
+    public elements: (CDecl | CDir)[],
+  ) {
+    super();
+  }
+}
+
+export type CNode
+  = CDecl
+  | CDir
+  | CStmt
+  | CExpr
+  | CType
+  | CProgram
+
+export class CEmitter {
+
+  private writer: IndentWriter;
+
+  public constructor(
+    public stream: stream.Writable,
+  ) {
+    this.writer = new IndentWriter(stream);
+  }
+
+  public emit(node: CNode): void {
+
+    switch (node.kind) {
+
+      case CNodeKind.Program:
+      {
+        for (const element of node.elements) {
+          this.emit(element);
+        }
+        break;
+      }
+
+      case CNodeKind.IncDir:
+      {
+        this.writer.write('#include ');
+        this.writer.write(node.isSystem ? '<' : '"');
+        this.writer.write(node.filePath);
+        this.writer.write(node.isSystem ? '>' : '"');
+        this.writer.write('\n\n');
+        break;
+      }
+
+      case CNodeKind.BuiltinType:
+      {
+        switch (node.typeKind) {
+          case CBuiltinTypeKind.Char:
+            this.writer.write('char');
+            break;
+          case CBuiltinTypeKind.Short:
+            this.writer.write('short');
+            break;
+          case CBuiltinTypeKind.Int:
+            this.writer.write('int');
+            break;
+          case CBuiltinTypeKind.Long:
+            this.writer.write('long');
+            break;
+          case CBuiltinTypeKind.LongLong:
+            this.writer.write('long long');
+            break;
+          case CBuiltinTypeKind.UnsignedChar:
+            this.writer.write('unsigned char');
+            break;
+          case CBuiltinTypeKind.UnsignedShort:
+            this.writer.write('unsigned short');
+            break;
+          case CBuiltinTypeKind.UnsignedInt:
+            this.writer.write('unsigned int');
+            break;
+          case CBuiltinTypeKind.UnsignedLong:
+            this.writer.write('unsigned long');
+            break;
+          case CBuiltinTypeKind.UnsignedLongLong:
+            this.writer.write('unsigned long long');
+            break;
+        }
+        break;
+      }
+
+      case CNodeKind.FuncDecl:
+      {
+        this.emit(node.returnType);
+        this.writer.write(' ' + node.name + '(');
+        let count = 0;
+        for (const [type, name] of node.params) {
+          this.emit(type);
+          this.writer.write(' ' + name);
+          if (count++ > 0) {
+            this.writer.write(', ');
+          }
+        }
+        this.writer.write(') {\n');
+        this.writer.indent();
+        if (node.body !== null) {
+          for (const element of node.body) {
+            this.emit(element);
+          }
+        }
+        this.writer.dedent();
+        this.writer.write('}\n\n');
+        break;
+      }
+
+      case CNodeKind.ExprStmt:
+        this.emit(node.expr);
+        this.writer.write(';\n');
+        break;
+
+      case CNodeKind.RetStmt:
+      {
+        this.writer.write('return');
+        if (node.value !== null) {
+          this.writer.write(' ');
+          this.emit(node.value);
+        }
+        this.writer.write(';\n');
+        break;
+      }
+
+      case CNodeKind.RefExpr:
+        this.writer.write(node.name);
+        break;
+
+      case CNodeKind.CallExpr:
+      {
+        this.emit(node.operator);
+        this.writer.write('(');
+        let count = 0;
+        for (const arg of node.args) {
+          this.emit(arg);
+          if (count++ > 0) {
+            this.writer.write(', ');
+          }
+        }
+        this.writer.write(')');
+        break;
+      }
+
+      case CNodeKind.ConstExpr:
+      {
+        if (typeof(node.value) === 'string') {
+          this.writer.write('"');
+          for (const ch of node.value) {
+            switch (ch) {
+              case '\b': this.writer.write('\\b'); break;
+              case '\f': this.writer.write('\\f'); break;
+              case '\n': this.writer.write('\\n'); break;
+              case '\r': this.writer.write('\\r'); break;
+              case '\t': this.writer.write('\\t'); break;
+              case '\v': this.writer.write('\\v'); break;
+              case '\0': this.writer.write('\\0'); break;
+              case '\'': this.writer.write('\\\''); break;
+              case '"': this.writer.write('\\"'); break;
+              default: this.writer.write(ch); break;
+            }
+          }
+          this.writer.write('"');
+        } else if (typeof(node.value) === 'bigint') {
+          this.writer.write(node.value.toString());
+        } else {
+          throw new Error(`Unexpected type of value in CConstExpr`);
+        }
+        break;
+      }
+
+      default:
+        throw new Error(`Unexpected ${node.constructor.name}`);
+
+    }
+
+  }
+
+}

src/codegen.ts

@@ -0,0 +1,82 @@
+
+import { CBuiltinType, CBuiltinTypeKind, CCallExpr, CConstExpr, CDecl, CDir, CExpr, CExprStmt, CFuncDecl, CIncDir, CProgram, CRefExpr, CStmt } from "./cast";
+import { Expression, SourceFile, Syntax, SyntaxKind } from "./cst";
+import { assert } from "./util";
+
+interface Context {
+  body: CStmt[];
+}
+
+export function generateCode(sourceFile: SourceFile): CProgram {
+
+  const intType = new CBuiltinType(CBuiltinTypeKind.Int);
+
+  const decls: (CDecl | CDir)[] = [];
+
+  decls.push(new CIncDir("runtime.h"));
+
+  const mainBody: CStmt[] = [];
+
+  decls.push(
+    new CFuncDecl(
+      intType,
+      'main',
+      [],
+      mainBody
+    )
+  );
+
+  visit(sourceFile, { body: mainBody });
+
+  return new CProgram(decls);
+
+  function visit(node: Syntax, context: Context): void {
+
+    switch (node.kind) {
+
+      case SyntaxKind.SourceFile:
+      {
+        for (const element of node.elements) {
+          visit(element, context);
+        }
+        break;
+      }
+
+      case SyntaxKind.ExpressionStatement:
+      {
+        context.body.push(
+          new CExprStmt(
+            visitExpression(node.expression, context)
+          )
+        );
+        break;
+      }
+
+      case SyntaxKind.LetDeclaration:
+      {
+        // TODO
+        break;
+      }
+
+    }
+
+  }
+
+  function visitExpression(node: Expression, context: Context): CExpr {
+    switch (node.kind) {
+      case SyntaxKind.ReferenceExpression:
+        assert(node.modulePath.length === 0);
+        return new CRefExpr(node.name.text);
+      case SyntaxKind.CallExpression:
+        const operator = visitExpression(node.func, context);
+        const args = node.args.map(arg => visitExpression(arg, context));
+        return new CCallExpr(operator, args);
+      case SyntaxKind.ConstantExpression:
+        return new CConstExpr(node.token.getValue());
+      default:
+        throw new Error(`Unexpected ${node}`);
+    }
+  }
+
+}
+

src/cst.ts

@@ -3,6 +3,10 @@ import type { InferContext, Kind, Scheme, Type, TypeEnv } from "./checker"
 
 export type TextSpan = [number, number];
 
+export type Value
+  = bigint
+  | string
+
 export class TextPosition {
 
   public constructor(
@@ -574,6 +578,10 @@ export class Integer extends TokenBase {
     super(startPos);
   }
 
+  public getValue(): Value {
+    return this.value;
+  }
+
   public get text(): string {
     switch (this.radix) {
       case 16:
@@ -602,6 +610,10 @@ export class StringLiteral extends TokenBase {
     super(startPos);
   }
 
+  public getValue(): Value {
+    return this.contents;
+  }
+
   public get text(): string {
     let out = '"';
     for (const ch of this.contents) {

src/diagnostics.ts

@@ -359,6 +359,8 @@ export type Diagnostic
   | KindMismatchDiagnostic
 
 export interface Diagnostics {
+  readonly hasError: boolean;
+  readonly hasFatal: boolean;
   add(diagnostic: Diagnostic): void;
 }
 
@@ -386,10 +388,20 @@ export class DiagnosticStore {
 }
 
 export class ConsoleDiagnostics {
+  
+  private writer = new IndentWriter(process.stderr);
+
+  public hasError = false;
+  public hasFatal = false;
 
   public add(diagnostic: Diagnostic): void {
-    const writer = new IndentWriter(process.stderr);
-    diagnostic.format(writer);
+    diagnostic.format(this.writer);
+    if (diagnostic.level >= Level.Error) {
+      this.hasError = true;
+    }
+    if (diagnostic.level >= Level.Fatal) {
+      this.hasFatal = true;
+    }
   }
 
 }

src/program.ts

@@ -0,0 +1,61 @@
+import path from "path";
+import fs from "fs"
+import { parseSourceFile } from ".";
+import { SourceFile, TextFile } from "./cst";
+import { ConsoleDiagnostics, Diagnostics } from "./diagnostics";
+import { Checker } from "./checker";
+import { Analyser } from "./analysis";
+import { generateCode } from "./codegen";
+import { CEmitter } from "./cast";
+
+export class Program {
+
+  private sourceFilesByPath = new Map<string, SourceFile>();
+
+  private analyser = new Analyser();
+
+  public constructor(
+    public fileNames: string[],
+    public diagnostics: Diagnostics = new ConsoleDiagnostics(),
+  ) {
+    for (const fileName of fileNames) {
+      const realPath = path.resolve(fileName);
+      const text = fs.readFileSync(realPath, 'utf-8');
+      const file = new TextFile(fileName, text);
+      const sourceFile = parseSourceFile(file, diagnostics);
+      if (sourceFile !== null) {
+        this.sourceFilesByPath.set(realPath, sourceFile);
+        this.analyser.addSourceFile(sourceFile);
+      }
+    }
+  }
+
+  public getSourceFiles(): Iterable<SourceFile> {
+    return this.sourceFilesByPath.values();
+  }
+
+  public check(): void {
+    const checker = new Checker(this.analyser, this.diagnostics);
+    for (const sourceFile of this.getSourceFiles()) {
+      checker.check(sourceFile);
+    }
+  }
+
+  public emit(): void {
+    for (const [filePath, sourceFile] of this.sourceFilesByPath) {
+      const file = fs.createWriteStream(stripExtension(filePath) + '.c', 'utf-8'); 
+      const emitter = new CEmitter(file);
+      emitter.emit(generateCode(sourceFile));
+    }
+  }
+
+}
+
+function stripExtension(filepath: string): string {
+  const basename = path.basename(filepath);
+  const i = basename.lastIndexOf('.');
+  if (i === -1) {
+    return filepath;
+  }
+  return path.join(path.dirname(filepath), basename.substring(0, i));
+}