Fix some bugs and add minimal support for imports

src/ast.ts

@@ -70,7 +70,7 @@ export enum SyntaxKind {
 
   VarDecl,
   FuncDecl,
-  ForeignDecl,
+  ImportDecl,
 
 }
 
@@ -920,6 +920,7 @@ export class VarDecl extends SyntaxBase {
   kind: SyntaxKind.VarDecl = SyntaxKind.VarDecl;
 
   constructor(
+    public isMutable: boolean,
     public bindings: Patt, 
     public typeDecl: TypeDecl | null,
     public value: Expr | null,
@@ -952,11 +953,32 @@ export class VarDecl extends SyntaxBase {
 
 }
 
+export class ImportDecl {
+
+  kind: SyntaxKind.ImportDecl = SyntaxKind.ImportDecl;
+
+  constructor(
+    public file: string,
+    public span: TextSpan | null = null,
+    public origNode: [Syntax, Syntax] | Syntax | null = null,
+    public parentNode: Syntax | null = null
+  ) {
+
+  }
+
+  *getChildren(): IterableIterator<Syntax> {
+
+  }
+
+}
+
 export type Decl
   = Sentence 
   | FuncDecl
+  | ImportDecl
   | VarDecl
 
+
 export type Syntax
   = Decl
   | Expr

src/bin/bolt.ts

@@ -183,14 +183,15 @@ yargs
       const compiler = new Compiler(checker, { target: "JS" })
       const bundle = compiler.compile(sourceFiles)
       const emitter = new Emitter()
-      for (const file of bundle) {
+      const outfiles = bundle.map(file => {
         const text = emitter.emit(file);
         fs.mkdirpSync('.bolt-work')
-        const filepath = path.join('.bolt-work', path.relative(process.cwd(), stripExtension(path.resolve(file.loc.source)) + '.js'))
+        const filepath = path.join('.bolt-work', path.relative(process.cwd(), stripExtension(path.resolve(file.loc.source)) + '.mjs'))
         fs.writeFileSync(filepath, text, 'utf8')
-        spawnSync('node', [filepath], { stdio: 'inherit' })
-      }
+        return filepath
+      })
 
+      spawnSync('node', [outfiles[0]], { stdio: 'inherit' })
     }
 
   )

src/checker.ts

@@ -1,7 +1,8 @@
 
 import {
   Syntax,
-  SyntaxKind
+  SyntaxKind,
+  ImportDecl,
 } from "./ast"
 
 class Type {
@@ -27,7 +28,7 @@ export class TypeChecker {
 
   protected scopes = new Map<Syntax, Scope>();
 
-  createType(node: Syntax) {
+  protected createType(node: Syntax) {
     switch (node.kind) {
       case SyntaxKind.ConstExpr:
         if (typeof node.value === 'bigint') {
@@ -38,6 +39,10 @@ export class TypeChecker {
     }
   }
 
+  getImportedSymbols(node: ImportDecl) {
+    return [{ name: 'fac' }]
+  }
+
   getScope(node: Syntax): Scope {
     while (node.kind !== SyntaxKind.FuncDecl && node.kind !== SyntaxKind.SourceFile) {
       node = node.parentNode!;

src/compiler.ts

@@ -96,6 +96,31 @@ export class Compiler {
 
     switch (node.kind) {
 
+      case SyntaxKind.ImportDecl:
+        preamble.push({
+          type: 'ImportDeclaration',
+          source: { type: 'Literal', value: node.file },
+          specifiers: this.checker.getImportedSymbols(node).map(s => ({
+            type: 'ImportSpecifier',
+            imported: { type: 'Identifier', name: s.name },
+            local: { type: 'Identifier', name: s.name },
+          })),
+        });
+        break;
+
+      case SyntaxKind.VarDecl:
+        const compiledValue = node.value !== null ? this.compileExpr(node.value, preamble) : null;
+        preamble.push({
+          type: 'VariableDeclaration',
+          kind: 'let',
+          declarations: [{
+            type: 'VariableDeclarator',
+            id: { type: 'Identifier', name: node.bindings.name.text },
+            init: compiledValue
+          }]
+        });
+        break;
+
       case SyntaxKind.FuncDecl:
         const params = [];
         if (node.target === this.target) {

src/expander.ts

@@ -18,6 +18,7 @@ export class Expander {
 
   constructor(public parser: Parser) {
     this.transformers.set('fn', parser.parseFuncDecl.bind(parser))
+    this.transformers.set('import', parser.parseImportDecl.bind(parser))
     this.transformers.set('foreign', parser.parseFuncDecl.bind(parser))
     this.transformers.set('let', parser.parseVarDecl.bind(parser))
     this.transformers.set('return', parser.parseRetStmt.bind(parser))

src/parser.ts

@@ -20,8 +20,8 @@ import {
   TypeDecl,
   ConstExpr,
   QualName,
-  ForeignDecl,
   CallExpr,
+  ImportDecl,
 } from "./ast"
 
 function describeKind(kind: SyntaxKind): string {
@@ -116,6 +116,20 @@ export class Parser {
     }
   }
 
+  parseImportDecl(tokens: TokenStream) {
+
+    // Assuming first keyword is 'import'
+    tokens.get();
+
+    const t0 = tokens.get();
+    if (t0.kind !== SyntaxKind.StringLiteral) {
+      throw new ParseError(t0, [SyntaxKind.StringLiteral])
+    }
+
+    return new ImportDecl(t0.value, null, t0);
+
+  }
+
   parseTypeDecl(tokens: TokenStream): TypeDecl {
     const t0 = tokens.peek();
     if (t0.kind === SyntaxKind.Identifier) {
@@ -170,9 +184,35 @@ export class Parser {
 
   parseVarDecl(tokens: TokenStream): VarDecl {
 
+    let isMutable = false;
+    let typeDecl = null;
+    let value = null;
+
     // Assuming first token is 'let'
     tokens.get();
 
+    const t0 = tokens.peek();
+    if (t0.kind === SyntaxKind.Identifier && t0.text === 'mut') {
+      tokens.get();
+      isMutable = true;
+    }
+
+    const bindings = this.parsePattern(tokens)
+
+    const t1 = tokens.peek();
+    if (t1.kind === SyntaxKind.Colon) {
+      tokens.get();
+      typeDecl = this.parseTypeDecl(tokens);
+    }
+
+    const t2 = tokens.peek();
+    if (t2.kind === SyntaxKind.EqSign) {
+      tokens.get();
+      value = this.parseExpr(tokens);
+    }
+
+    return new VarDecl(isMutable, bindings, typeDecl, value, null)
+
   }
 
   parseRetStmt(tokens: TokenStream): RetStmt {
@@ -206,7 +246,7 @@ export class Parser {
 
     let target = "Bolt";
 
-    const k0 = tokens.get();
+    const k0 = tokens.peek();
     if (k0.kind !== SyntaxKind.Identifier) {
       throw new ParseError(k0, [SyntaxKind.ForeignKeyword, SyntaxKind.FunctionKeyword])
     }
@@ -218,7 +258,7 @@ export class Parser {
       target = l1.value;
     }
     const k1 = tokens.get();
-    if (k1.text !== 'fn') {
+    if (k1.kind !== SyntaxKind.Identifier || k1.text !== 'fn') {
       throw new ParseError(k1, [SyntaxKind.FunctionKeyword])
     }
 

src/scanner.ts

@@ -23,6 +23,7 @@ import {
   IntegerLiteral,
   Colon,
   EOS,
+  EqSign,
 } from "./ast"
 
 function escapeChar(ch: string) {
@@ -200,6 +201,9 @@ export class Scanner {
       }
 
       switch (c0) {
+        case '=':
+          this.getChar();
+          return new EqSign(new TextSpan(this.file, startPos, this.currPos.clone()));
         case ';':
           this.getChar();
           return new Semi(new TextSpan(this.file, startPos, this.currPos.clone()));