Add Diagnostic Parser Agent Skill

// src/diagnostics/util.ts (simplified)
export abstract class RawDiagnosticParser {
    get diagnostics(): readonly RawDiagnostic[] { /* accumulated results */ }

    /** Called by the build consumer for every line of output. */
    handleLine(line: string): boolean {
        const result = this.doHandleLine(line);
        if (result === FeedLineResult.Ok) return true;        // line consumed, no new diagnostic
        if (result === FeedLineResult.NotMine) return false;   // line not recognized
        // Otherwise result is a RawDiagnostic — it gets stored automatically
        this._diagnostics.push(result);
        return true;
    }

    /** Implement this. Return a RawDiagnostic to emit, or a FeedLineResult. */
    protected abstract doHandleLine(line: string): RawDiagnostic | FeedLineResult;
}

/**
 * Module for parsing <ToolName> diagnostics
 */ /** */

import * as vscode from 'vscode';
import { oneLess, RawDiagnosticParser, FeedLineResult } from '@cmt/diagnostics/util';

// Regex that captures: file, line, severity, code (optional), message
export const REGEX = /^(.+):(\d+):\s+(error|warning|info)\s+(\w+):\s+(.*)$/;

export class Parser extends RawDiagnosticParser {
    doHandleLine(line: string) {
        const mat = REGEX.exec(line);
        if (!mat) {
            return FeedLineResult.NotMine;
        }
        const [full, file, lineStr, severity, code, message] = mat;
        const lineno = oneLess(lineStr);   // convert 1-based to 0-based
        return {
            full,
            file,
            location: new vscode.Range(lineno, 0, lineno, 999),
            severity,
            message,
            code,
            related: []
        };
    }
}

import { RawDiagnosticParser, RawDiagnostic, FeedLineResult, oneLess } from '@cmt/diagnostics/util';

enum ParserState { init, pending_message }

export class Parser extends RawDiagnosticParser {
    private state = ParserState.init;
    private pending: RawDiagnostic | null = null;

    doHandleLine(line: string): RawDiagnostic | FeedLineResult {
        switch (this.state) {
            case ParserState.init: {
                const mat = FIRST_LINE_REGEX.exec(line);
                if (!mat) return FeedLineResult.NotMine;
                this.pending = { /* ... build partial diagnostic ... */ };
                this.state = ParserState.pending_message;
                return FeedLineResult.Ok;  // consumed, but not complete yet
            }
            case ParserState.pending_message: {
                if (/* line completes the diagnostic */) {
                    const diag = this.pending!;
                    this.reset();
                    return diag;           // emits the diagnostic
                }
                return FeedLineResult.Ok;  // still accumulating
            }
        }
        return FeedLineResult.NotMine;
    }
}

// src/diagnostics/util.ts
interface RawDiagnostic {
    full: string;               // the full matched line(s)
    file: string;               // source file path
    location: vscode.Range;     // 0-based range (use oneLess() for 1-based input)
    severity: string;           // 'error' | 'warning' | 'note' | 'info' | 'fatal error' | 'remark'
    message: string;
    code?: string;              // optional diagnostic code (e.g. 'C4996', 'LNK2019')
    related: RawRelated[];      // related diagnostics (notes, template backtraces)
}

enum FeedLineResult {
    Ok,       // line was consumed (but no new diagnostic produced yet)
    NotMine,  // line not recognized by this parser
}

// At the top — add import
import * as myparser from '@cmt/diagnostics/myparser';

// Inside the Compilers class — add property
export class Compilers {
    [compiler: string]: RawDiagnosticParser;

    gcc = new gcc.Parser();
    gnuld = new gnu_ld.Parser();
    ghs = new ghs.Parser();
    diab = new diab.Parser();
    msvc = new mvsc.Parser();
    iar = new iar.Parser();
    iwyu = new iwyu.Parser();
    myparser = new myparser.Parser();   // ← new parser
}

// package.json → contributes.configuration → cmake.enabledOutputParsers
"cmake.enabledOutputParsers": {
    "type": "array",
    "items": {
        "type": "string",
        "enum": [
            "cmake",
            "gcc",
            "gnuld",
            "msvc",
            "ghs",
            "diab",
            "iar",
            "iwyu",
            "myparser"     // ← add to enum
        ]
    },
    "default": [
        "cmake",
        "gcc",
        "gnuld",
        "msvc",
        "ghs",
        "diab"
        // only add here if default-enabled
    ]
}

test('Parse <tool> error', () => {
    const build_consumer = new diags.CompileOutputConsumer(
        new ConfigurationReader({} as ExtensionConfigurationSettings)
    );
    // Feed real compiler output lines
    build_consumer.error('<tool-specific output line>');

    // Verify diagnostics
    const parser = build_consumer.compilers.myparser;
    expect(parser.diagnostics).to.have.length(1);
    expect(parser.diagnostics[0].severity).to.eq('error');
    expect(parser.diagnostics[0].file).to.eq('expected/file.cpp');
});

Features:
- Add `myparser` diagnostic parser for <ToolName> compiler output. [PR #XXXX](https://github.com/microsoft/vscode-cmake-tools/pull/XXXX)