Improve preprocessor error reporting

packages/compiler/src/compiler/codegen.ts

@@ -6,7 +6,7 @@ import {
     laxRead, itemText,
 
     Items, Pattern, Templates, Substitution, TokenType,
-    SourceMap, CodeWriter, TemplateFunction, Token, SpanIndex,
+    SourceMap, CodeWriter, TemplateFunction, Token, SpanIndex, match, TokenBase, getRange, Pos,
 } from '../syntax/index.js';
 import {
     SyndicateParser, SyndicateTypedParser,
@@ -29,7 +29,7 @@ export function stripShebang(items: Items): Items {
 
 export type ModuleType ='es6' | 'require' | 'global';
 
-export type ErrorSink = (message: string) => void;
+export type ErrorSink = (message: string, start: Pos | undefined, end: Pos | undefined) => void;
 
 export interface CompileOptions {
     source: string,
@@ -52,17 +52,17 @@ export class ExpansionContext {
     readonly parser: SyndicateParser;
     readonly moduleType: ModuleType;
     readonly typescript: boolean;
-    readonly emitError: (message: string) => void;
+    readonly errorEmitter: ErrorSink;
     nextIdNumber = 0;
 
     constructor(moduleType: ModuleType,
                 typescript: boolean,
-                emitError: ErrorSink)
+                errorEmitter: ErrorSink)
     {
         this.parser = typescript ? new SyndicateTypedParser : new SyndicateParser();
         this.moduleType = moduleType;
         this.typescript = typescript;
-        this.emitError = emitError;
+        this.errorEmitter = errorEmitter;
     }
 
     quasiRandomId(): string {
@@ -72,6 +72,10 @@ export class ExpansionContext {
     argDecl(t: TemplateFunction, name: Substitution, type: Substitution): Items {
         return (this.typescript) ? t`${name}: ${type}` : t`${name}`;
     }
+
+    emitError(m: string, loc: TokenBase) {
+        this.errorEmitter(m, loc.start, loc.end);
+    }
 }
 
 function stringifyId(i: Identifier): Items {
@@ -99,7 +103,8 @@ function binderTypeGuard(ctx: ExpansionContext, t: TemplateFunction): (binder: B
                 case 'any':
                     return bind;
                 default:
-                    ctx.emitError(`Cannot emit guard for binding of type: ${JSON.stringify(typeText)}`);
+                    ctx.emitError(`Cannot emit guard for binding of type: ${JSON.stringify(typeText)}`,
+                                  getRange(binder.type));
                     return bind; /* act as if "any", for now */
             }
         }

packages/compiler/src/compiler/grammar.ts

@@ -2,13 +2,13 @@
 /// SPDX-FileCopyrightText: Copyright © 2016-2021 Tony Garnock-Jones <tonyg@leastfixedpoint.com>
 
 import {
-    Token, Item, Items,
+    Token, Items,
     Pattern,
     foldItems, match, anonymousTemplate as template, commaJoin,
 
     scope, bind, seq, alt, upTo, atom, atomString, group,
     repeat, option, withoutSpace, map, mapm, rest, discard,
-    value, succeed, fail, separatedOrTerminatedBy, anything, not
+    value, succeed, fail, separatedOrTerminatedBy, not, TokenBase
 } from '../syntax/index.js';
 import * as Matcher from '../syntax/matcher.js';
 

packages/compiler/src/syntax/position.ts

@@ -9,6 +9,10 @@ export interface Pos {
     fixed?: boolean;
 }
 
+export function formatPos(p?: Pos): string {
+    return p ? `${p.name ?? '?'}:${p.line}:${p.column}` : '?';
+}
+
 export function startPos(name: string | null): Pos {
     return { line: 1, column: 0, pos: 0, name };
 }

packages/compiler/src/syntax/tokens.ts

@@ -34,6 +34,14 @@ export type Items = Array<Item>;
 
 export type GroupInProgress = Omit<Group, 'end'>;
 
+export function getRange(t: Item | Items): TokenBase {
+    if (Array.isArray(t)) {
+        return { start: t[0].start, end: t[t.length - 1].end, synthetic: true };
+    } else {
+        return t;
+    }
+}
+
 export function finishGroup(g: GroupInProgress, end: Pos): Group {
     return { ... g, end };
 }

packages/syndicatec/src/cli.ts

@@ -7,7 +7,7 @@ import fs from 'fs';
 import path from 'path';
 import { glob } from 'glob';
 
-import { compile } from '@syndicate-lang/compiler';
+import { compile, Syntax } from '@syndicate-lang/compiler';
 import { dataURL, sourceMappingComment} from './util.js';
 
 export type ModuleChoice = 'es6' | 'require' | 'global';
@@ -117,7 +117,7 @@ export function main(argv: string[]) {
                  argv => argv)
         .argv);
 
-    const collectedErrors: Array<string> = [];
+    let errorCount = 0;
 
     const rename = makeRenamer(options.outputDirectory ?? '',
                                options.rootDirectory ?? '.',
@@ -146,9 +146,9 @@ export function main(argv: string[]) {
             runtime: options.runtime,
             module: options.module,
             typescript: options.typed,
-            emitError: m => {
+            emitError: (m, start, end) => {
-                console.error(m);
+                console.error(`${Syntax.formatPos(start)}-${Syntax.formatPos(end)}: ${m}`);
-                collectedErrors.push(m);
+                errorCount++;
             }
         });
         map.sourcesContent = [source];
@@ -168,7 +168,7 @@ export function main(argv: string[]) {
         }
     }
 
-    if (collectedErrors.length > 0) {
+    if (errorCount > 0) {
-        throw new Error(`Compilation failed with ${collectedErrors.length} error(s).`);
+        throw new Error(`Compilation failed with ${errorCount} error(s).`);
     }
 }

packages/ts-plugin/src/index.ts

@@ -11,6 +11,7 @@ const boot: tslib.server.PluginModuleFactory = ({ typescript: ts }) => {
     interface SyndicateInfo {
         sourceFile: ts.SourceFile;
         originalSource: string;
+        diagnostics: ts.DiagnosticWithLocation[];
         targetToSourceMap: Syntax.SpanIndex<Syntax.Token>;
         sourceToTargetMap: Syntax.SpanIndex<number>;
     }
@@ -159,20 +160,30 @@ const boot: tslib.server.PluginModuleFactory = ({ typescript: ts }) => {
                             onError?.(`Could not read input file ${fileName}`);
                             return undefined;
                         }
+                        const diagnostics:
+                            Array<{ message: string, start?: Syntax.Pos, end?: Syntax.Pos }> = [];
                         console.log('Syndicate compiling', fileName);
                         const { text: expandedText, targetToSourceMap, sourceToTargetMap } = compile({
                             source: inputText,
                             name: fileName,
                             typescript: true,
-                            emitError: m => {
+                            emitError: (message, start, end) => {
-                                console.error(m);
+                                console.error(`${Syntax.formatPos(start)}-${Syntax.formatPos(end)}: ${message}`);
-                                onError?.(m);
+                                diagnostics.push({ message, start, end });
                             },
                         });
                         const sf = ts.createSourceFile(fileName, expandedText, languageVersion, true);
                         syndicateInfo.set(fileName, {
                             sourceFile: sf,
                             originalSource: inputText,
+                            diagnostics: diagnostics.map(({ message, start, end }) => ({
+                                category: ts.DiagnosticCategory.Error,
+                                code: 99999,
+                                file: sf,
+                                start: start?.pos ?? 0,
+                                length: Math.max(0, (end?.pos ?? 0) - (start?.pos ?? 0)),
+                                messageText: message,
+                            })),
                             targetToSourceMap,
                             sourceToTargetMap,
                         });
@@ -243,7 +254,11 @@ const boot: tslib.server.PluginModuleFactory = ({ typescript: ts }) => {
 
         getSyntacticDiagnostics(fileName: string): ts.DiagnosticWithLocation[] {
             const ds = this.inner.getSyntacticDiagnostics(fileName);
-            return withFileName(fileName, () => ds, (fixup) => fixup.diagnostics(ds));
+            return withFileName(fileName, () => ds, (fixup) => {
+                const fixedUp = fixup.diagnostics(ds);
+                fixedUp.push(... fixup.info.diagnostics);
+                return fixedUp;
+            });
         }
 
         getSemanticDiagnostics(fileName: string): ts.Diagnostic[] {

packages/tsc/src/tsc.ts

@@ -8,7 +8,7 @@ import crypto from 'crypto';
 import fs from 'fs';
 import path from 'path';
 
-import { compile } from '@syndicate-lang/compiler';
+import { compile, Syntax } from '@syndicate-lang/compiler';
 import { SpanIndex, Token } from '@syndicate-lang/compiler/lib/syntax';
 
 export type CommandLineArguments = {
@@ -150,8 +150,8 @@ function runBuildOnce(options: CommandLineArguments, toWatch = new ToWatch()) {
                             source: inputText,
                             name: fileName,
                             typescript: true,
-                            emitError: m => {
+                            emitError: (m, start, end) => {
-                                console.error(m);
+                                console.error(`${Syntax.formatPos(start)}-${Syntax.formatPos(end)}: ${m}`);
                                 onError?.(m);
                             },
                         });