Macroforge MCP Server

# PositionMapper macroforge v0.1.43 Bidirectional position mapper for translating between original and expanded source positions. This mapper enables IDE features like error reporting, go-to-definition, and hover to work correctly with macro-expanded code by translating positions between the original source (what the user wrote) and the expanded source (what the compiler sees). ## Getting a Mapper TypeScript ``` import { NativePlugin, PositionMapper } from "macroforge"; const plugin = new NativePlugin(); const result = plugin.processFile("user.ts", code, { version: "1" }); // Get the mapper for this file const mapper = plugin.getMapper("user.ts"); if (mapper) {   // Use the mapper... } ``` ## Methods ### isEmpty() Check if the mapper has any mappings: TypeScript ``` isEmpty(): boolean ``` ### originalToExpanded() Map a position from original to expanded code: TypeScript ``` originalToExpanded(pos: number): number ``` ### expandedToOriginal() Map a position from expanded to original code: TypeScript ``` expandedToOriginal(pos: number): number | null ``` Returns `null` if the position is in generated code. ### isInGenerated() Check if a position is in macro-generated code: TypeScript ``` isInGenerated(pos: number): boolean ``` ### generatedBy() Get the name of the macro that generated code at a position: TypeScript ``` generatedBy(pos: number): string | null ``` ### mapSpanToOriginal() Map a span (range) from expanded to original code: TypeScript ``` mapSpanToOriginal(start: number, length: number): SpanResult | null interface SpanResult {   start: number;   length: number; } ``` ### mapSpanToExpanded() Map a span from original to expanded code: TypeScript ``` mapSpanToExpanded(start: number, length: number): SpanResult ``` ## Example: Error Position Mapping TypeScript ``` import { NativePlugin } from "macroforge"; const plugin = new NativePlugin(); function mapError(filepath: string, expandedPos: number, message: string) { const mapper = plugin.getMapper(filepath); if (!mapper) return null; // Check if the error is in generated code if (mapper.isInGenerated(expandedPos)) { const macroName = mapper.generatedBy(expandedPos); return { message: `Error in code generated by @derive(${macroName}): ${message}`, // Find the @derive decorator position position: findDecoratorPosition(filepath) }; } // Map to original position const originalPos = mapper.expandedToOriginal(expandedPos); if (originalPos !== null) { return { message, position: originalPos }; } return null; } ``` ## Performance Position mapping uses binary search with O(log n) complexity: * Fast lookups even for large files * Minimal memory overhead * Thread-safe access