refactorings

src/ast.ts

@@ -1,6 +1,6 @@
-import { DUMMY_SPAN, LoadedFile, Span } from "./error";
+import { LoadedFile, Span } from "./error";
 import { LitIntType } from "./lexer";
-import { ComplexMap, unwrap } from "./utils";
+import { ComplexMap } from "./utils";
 
 export type Phase = {
   res: unknown;
@@ -57,7 +57,7 @@ export type Crate<P extends Phase> = {
   rootItems: Item<P>[];
   itemsById: ComplexMap<ItemId, Item<P>>;
   packageName: string;
-  rootFile: LoadedFile,
+  rootFile: LoadedFile;
 } & P["typeckResults"];
 
 export type DepCrate = Crate<Final>;
@@ -85,6 +85,10 @@ export class ItemId {
     return new ItemId(999999, 999999);
   }
 
+  static crateRoot(crate: CrateId): ItemId {
+    return new ItemId(crate, 0);
+  }
+
   toString(): string {
     if (this.crateId === 0) {
       return `${this.itemIdx}`;
@@ -535,29 +539,6 @@ export type TypeckResults = {
   main: Resolution | undefined;
 };
 
-export function findCrateItem<P extends Phase>(
-  crate: Crate<P>,
-  id: ItemId
-): Item<P> {
-  if (id.crateId !== crate.id) {
-    throw new Error("trying to get item from the wrong crate");
-  }
-  if (id.itemIdx === 0) {
-    // Return a synthetic module representing the crate root.
-    return {
-      kind: "mod",
-      node: {
-        contents: crate.rootItems,
-        name: crate.packageName,
-      },
-      span: DUMMY_SPAN,
-      id,
-    };
-  }
-
-  return unwrap(crate.itemsById.get(id));
-}
-
 // folders
 
 export type FoldFn<From, To> = (value: From) => To;

src/context.ts

@@ -1,5 +1,5 @@
 import { Crate, DepCrate, Final, Item, ItemId, Phase } from "./ast";
-import { DUMMY_SPAN, Span } from "./error";
+import { Span } from "./error";
 import { Ids, unwrap } from "./utils";
 import fs from "fs";
 import path from "path";
@@ -20,17 +20,19 @@ export type CrateLoader = (
  * dependencies (which also use the same context) do not care about that.
  */
 export class GlobalContext {
-  public depCrates: Crate<Final>[] = [];
+  public finalizedCrates: Crate<Final>[] = [];
   public crateId: Ids = new Ids();
 
   constructor(public opts: Options, public crateLoader: CrateLoader) {}
 
   public findItem<P extends Phase>(
     id: ItemId,
-    localCrate: Crate<P>
+    localCrate?: Crate<P>
   ): Item<P | Final> {
     const crate = unwrap(
-      [localCrate, ...this.depCrates].find((crate) => crate.id === id.crateId)
+      [...(localCrate ? [localCrate] : []), ...this.finalizedCrates].find(
+        (crate) => crate.id === id.crateId
+      )
     );
 
     if (id.itemIdx === 0) {
@@ -41,7 +43,7 @@ export class GlobalContext {
           contents: crate.rootItems,
           name: crate.packageName,
         },
-        span: DUMMY_SPAN,
+        span: Span.startOfFile(crate.rootFile),
         id,
       };
     }

src/error.ts

@@ -3,30 +3,35 @@ export type LoadedFile = {
   content: string;
 };
 
-export type Span = {
+export class Span {
-  start: number;
+  constructor(
-  end: number;
+    public start: number,
-  file: LoadedFile;
+    public end: number,
-};
+    public file: LoadedFile
+  ) {}
 
-export function spanMerge(a: Span, b: Span): Span {
+  public merge(b: Span): Span {
-  if (a.file !== b.file) {
+    if (this.file !== b.file) {
-    throw new Error("cannot merge spans from different files");
+      throw new Error("cannot merge spans from different files");
+    }
+
+    return new Span(
+      Math.min(this.start, b.start),
+      Math.max(this.end, b.end),
+      this.file
+    );
   }
 
-  return {
+  public static eof(file: LoadedFile): Span {
-    start: Math.min(a.start, b.start),
+    return new Span(Number.MAX_SAFE_INTEGER, Number.MAX_SAFE_INTEGER, file);
-    end: Math.max(a.end, b.end),
+  }
-    file: a.file,
-  };
-}
 
-export const DUMMY_SPAN: Span = { start: 0, end: 0, file: { content: "" } };
+  public static startOfFile(file: LoadedFile): Span {
-export const eofSpan = (file: LoadedFile): Span => ({
+    return new Span(0, 1, file);
-  start: Number.MAX_SAFE_INTEGER,
+  }
-  end: Number.MAX_SAFE_INTEGER,
+
-  file,
+  public static DUMMY: Span = new Span(0, 0, { content: "" });
-});
+}
 
 export class CompilerError extends Error {
   msg: string;
@@ -98,11 +103,11 @@ function spanToSnippet(input: string, span: Span): string {
 }
 
 export function lines(file: LoadedFile): Span[] {
-  const lines: Span[] = [{ start: 0, end: 0, file }];
+  const lines: Span[] = [new Span(0, 0, file)];
 
   for (let i = 0; i < file.content.length; i++) {
     if (file.content[i] === "\n") {
-      lines.push({ start: i + 1, end: i + 1, file });
+      lines.push(new Span(i + 1, i + 1, file));
     } else {
       lines[lines.length - 1].end++;
     }

src/index.ts

@@ -1,4 +1,4 @@
-import { LoadedFile, withErrorPrinter } from "./error";
+import { LoadedFile, Span, withErrorPrinter } from "./error";
 import { isValidIdent, tokenize } from "./lexer";
 import { lower as lowerToWasm } from "./lower";
 import { ParseState, parse } from "./parser";
@@ -13,8 +13,6 @@ import { GlobalContext, parseArgs } from "./context";
 import { loadCrate } from "./loader";
 
 const INPUT = `
-extern mod std;
-
 type A = { a: Int };
 
 function main() = (
@@ -49,6 +47,8 @@ function main() {
   const gcx = new GlobalContext(opts, loadCrate);
   const mainCrate = gcx.crateId.next();
 
+  gcx.crateLoader(gcx, "std", Span.startOfFile(file));
+
   withErrorPrinter(
     () => {
       const start = Date.now();
@@ -93,7 +93,9 @@ function main() {
       if (debug.has("wat")) {
         console.log("-----wasm--------------");
       }
-      const wasmModule = lowerToWasm([typecked, ...gcx.depCrates]);
+
+      gcx.finalizedCrates.push(typecked);
+      const wasmModule = lowerToWasm(gcx);
       const moduleStringColor = writeModuleWatToString(wasmModule, true);
       const moduleString = writeModuleWatToString(wasmModule);
 

src/lexer.test.ts

@@ -3,7 +3,7 @@ import { tokenize } from "./lexer";
 it("should tokenize an emtpy function", () => {
   const input = `function hello() = ;`;
 
-  const tokens = tokenize(input);
+  const tokens = tokenize({ content: input });
 
   expect(tokens).toMatchSnapshot();
 });
@@ -11,7 +11,7 @@ it("should tokenize an emtpy function", () => {
 it("should tokenize hello world", () => {
   const input = `print("hello world")`;
 
-  const tokens = tokenize(input);
+  const tokens = tokenize({ content: input });
 
   expect(tokens).toMatchSnapshot();
 });

src/lexer.ts

@@ -92,7 +92,7 @@ export function tokenize(file: LoadedFile): Token[] {
 
   finish: while (i < input.length) {
     const next = input[i];
-    const span: Span = { start: i, end: i + 1, file };
+    const span: Span = new Span(i, i + 1, file);
 
     if (next === "/" && input[i + 1] === "/") {
       while (input[i] !== "\n") {
@@ -206,7 +206,7 @@ export function tokenize(file: LoadedFile): Token[] {
                 default:
                   throw new CompilerError(
                     `invalid escape character: ${input[i]}`,
-                    { start: span.end - 1, end: span.end, file }
+                    new Span(span.end - 1, span.end, file)
                   );
               }
               continue;

src/loader.ts

@@ -45,7 +45,7 @@ export const loadCrate: CrateLoader = (
   // We really, really want a good algorithm for finding crates.
   // But right now we just look for files in the CWD.
 
-  const existing = gcx.depCrates.find((crate) => crate.packageName === name);
+  const existing = gcx.finalizedCrates.find((crate) => crate.packageName === name);
   if (existing) {
     return existing;
   }
@@ -64,7 +64,7 @@ export const loadCrate: CrateLoader = (
 
       const typecked = typeck(gcx, resolved);
 
-      gcx.depCrates.push(typecked);
+      gcx.finalizedCrates.push(typecked);
       return typecked;
     },
     () => {

src/lower.ts

@@ -2,7 +2,6 @@ import {
   Crate,
   Expr,
   ExprBlock,
-  Final,
   Folder,
   FunctionDef,
   GlobalItem,
@@ -16,12 +15,12 @@ import {
   TyStruct,
   TyTuple,
   Typecked,
-  findCrateItem,
   mkDefaultFolder,
   superFoldExpr,
   superFoldItem,
   varUnreachable,
 } from "./ast";
+import { GlobalContext } from "./context";
 import { printTy } from "./printer";
 import { ComplexMap, encodeUtf8, unwrap } from "./utils";
 import * as wasm from "./wasm/defs";
@@ -61,7 +60,7 @@ export type Context = {
   reservedHeapMemoryStart: number;
   funcIndices: ComplexMap<Resolution, FuncOrImport>;
   globalIndices: ComplexMap<Resolution, wasm.GlobalIdx>;
-  crates: Crate<Final>[];
+  gcx: GlobalContext;
   relocations: Relocation[];
   knownDefPaths: ComplexMap<string[], ItemId>;
 };
@@ -112,13 +111,6 @@ function appendData(cx: Context, newData: Uint8Array): number {
   }
 }
 
-function findItem(cx: Context, id: ItemId): Item<Typecked> {
-  return findCrateItem(
-    unwrap(cx.crates.find((crate) => crate.id === id.crateId)),
-    id
-  );
-}
-
 const KNOWN_DEF_PATHS = [ALLOCATE_ITEM];
 
 function getKnownDefPaths(
@@ -155,8 +147,8 @@ function getKnownDefPaths(
   return knows;
 }
 
-export function lower(crates: Crate<Final>[]): wasm.Module {
+export function lower(gcx: GlobalContext): wasm.Module {
-  const knownDefPaths = getKnownDefPaths(crates);
+  const knownDefPaths = getKnownDefPaths(gcx.finalizedCrates);
 
   const mod: wasm.Module = {
     types: [],
@@ -183,12 +175,12 @@ export function lower(crates: Crate<Final>[]): wasm.Module {
   });
 
   const cx: Context = {
+    gcx,
     mod,
     funcTypes: new ComplexMap(),
     funcIndices: new ComplexMap(),
     globalIndices: new ComplexMap(),
     reservedHeapMemoryStart: 0,
-    crates,
     relocations: [],
     knownDefPaths,
   };
@@ -221,7 +213,7 @@ export function lower(crates: Crate<Final>[]): wasm.Module {
       }
     });
   }
-  crates.forEach((ast) => lowerMod(ast.rootItems));
+  gcx.finalizedCrates.forEach((ast) => lowerMod(ast.rootItems));
 
   const HEAP_ALIGN = 0x08;
   cx.reservedHeapMemoryStart =
@@ -229,7 +221,7 @@ export function lower(crates: Crate<Final>[]): wasm.Module {
       ? (mod.datas[0].init.length + (HEAP_ALIGN - 1)) & ~(HEAP_ALIGN - 1)
       : 0;
 
-  addRt(cx, crates);
+  addRt(cx, gcx.finalizedCrates);
 
   // THE LINKER
   const offset = cx.mod.imports.length;
@@ -447,7 +439,7 @@ function lowerExpr(
               break;
             }
             case "item": {
-              const item = findItem(fcx.cx, res.id);
+              const item = fcx.cx.gcx.findItem(res.id);
               if (item.kind !== "global") {
                 throw new Error("cannot store to non-global item");
               }
@@ -529,7 +521,7 @@ function lowerExpr(
           break;
         }
         case "item": {
-          const item = findItem(fcx.cx, res.id);
+          const item = fcx.cx.gcx.findItem(res.id);
           switch (item.kind) {
             case "global": {
               const instr: wasm.Instr = { kind: "global.get", imm: DUMMY_IDX };

src/parser.ts

@@ -32,7 +32,7 @@ import {
   GlobalItem,
   StructLiteralField,
 } from "./ast";
-import { CompilerError, eofSpan, LoadedFile, Span, spanMerge } from "./error";
+import { CompilerError, LoadedFile, Span } from "./error";
 import { BaseToken, Token, TokenIdent, TokenLitString } from "./lexer";
 import { ComplexMap, ComplexSet, Ids } from "./utils";
 
@@ -297,7 +297,7 @@ function mkParserExprBinary(
       [t, tok] = next(t);
       let rhs;
       [t, rhs] = parser(t);
-      const span = spanMerge(lhs.span, rhs.span);
+      const span = lhs.span.merge(rhs.span);
 
       return [t, mkExpr(lhs, rhs, span, tok.kind)];
     }
@@ -380,7 +380,7 @@ function parseExprCall(t: State): [State, Expr<Parsed>] {
         kind: "fieldAccess",
         lhs,
         field: { span: access.span, value },
-        span: spanMerge(lhs.span, access.span),
+        span: lhs.span.merge(access.span),
       };
     }
   }
@@ -676,7 +676,7 @@ function expectNext<T extends BaseToken>(
   if (!tok) {
     throw new CompilerError(
       `expected \`${kind}\`, found end of file`,
-      eofSpan(t.file)
+      Span.eof(t.file)
     );
   }
   if (tok.kind !== kind) {
@@ -691,7 +691,7 @@ function expectNext<T extends BaseToken>(
 function next(t: State): [State, Token] {
   const [rest, next] = maybeNextT(t);
   if (!next) {
-    throw new CompilerError("unexpected end of file", eofSpan(t.file));
+    throw new CompilerError("unexpected end of file", Span.eof(t.file));
   }
   return [rest, next];
 }

src/resolve.ts

@@ -19,7 +19,7 @@ import {
   ExternItem,
 } from "./ast";
 import { GlobalContext } from "./context";
-import { CompilerError, spanMerge } from "./error";
+import { CompilerError } from "./error";
 import { ComplexMap } from "./utils";
 
 const BUILTIN_SET = new Set<string>(BUILTINS);
@@ -128,11 +128,14 @@ function resolveModule(
       };
     }
 
-    if (ident.name === cx.ast.packageName) {
+    // All loaded crates are in scope.
-      return {
+    for (const crate of [cx.ast, ...cx.gcx.finalizedCrates]) {
-        kind: "item",
+      if (ident.name === crate.packageName) {
-        id: new ItemId(cx.ast.id, 0),
+        return {
-      };
+          kind: "item",
+          id: ItemId.crateRoot(crate.id),
+        };
+      }
     }
 
     if (BUILTIN_SET.has(ident.name)) {
@@ -278,7 +281,7 @@ function resolveModule(
                   kind: "path",
                   segments: [...segments, expr.field.value],
                   res: pathRes,
-                  span: spanMerge(lhs.span, expr.field.span),
+                  span: lhs.span.merge(expr.field.span),
                 };
               }
             }

src/typeck.test.ts

@@ -1,7 +1,9 @@
 import { TY_INT, TY_STRING, TY_UNIT } from "./ast";
-import { DUMMY_SPAN as SPAN } from "./error";
+import { Span } from "./error";
 import { InferContext } from "./typeck";
 
+const SPAN: Span = Span.startOfFile({content: ""});
+
 it("should infer types across assignments", () => {
   const infcx = new InferContext();
 

src/typeck.ts

@@ -28,7 +28,6 @@ import {
   Typecked,
   TyStruct,
   Item,
-  findCrateItem,
   StructLiteralField,
 } from "./ast";
 import { GlobalContext } from "./context";
@@ -154,7 +153,7 @@ export function typeck(
       }
     }
 
-    const item = findCrateItem(ast, itemId);
+    const item = gcx.findItem(itemId, ast);
     const ty = itemTys.get(itemId);
     if (ty) {
       return ty;
@@ -420,11 +419,10 @@ export function typeck(
   if (ast.id === 0) {
     // Only the final id=0 crate needs and cares about main.
     if (!main) {
-      throw new CompilerError(`\`main\` function not found`, {
+      throw new CompilerError(
-        start: 0,
+        `\`main\` function not found`,
-        end: 1,
+        Span.startOfFile(ast.rootFile)
-        file: ast.rootFile,
+      );
-      });
     }
 
     typecked.typeckResults = {