Notepad3/CLAUDE.md

CLAUDE.md

This file provides guidance to Claude Code (claude.ai/code) when working with code in this repository.

Project Overview

Notepad3 is a Windows-only Win32 desktop text editor (C/C++) built on Scintilla (editing component) and Lexilla (syntax highlighting). It ships with companion tools MiniPath (file browser, Ctrl+M) and grepWinNP3 (file search/grep, Ctrl+Shift+F). Licensed under BSD 3-Clause.

Build Commands

# NuGet restore (required before first build)
nuget restore Notepad3.sln

# Single platform builds
Build\Build_x64.cmd [Release|Debug]
Build\Build_Win32.cmd [Release|Debug]
Build\Build_ARM64.cmd [Release|Debug]
Build\Build_x64_AVX2.cmd [Release|Debug]

# All platforms at once
Build\BuildAll.cmd [Release|Debug]

# MSBuild directly (used by CI)
msbuild Notepad3.sln /m /p:Configuration=Release /p:Platform=x64

# Clean all outputs
Build\Clean.cmd

Default configuration is Release. Build scripts delegate to PowerShell in Build\scripts\.

Versioning

Run Version.ps1 before building to generate src\VersionEx.h from templates in Versions\. Format: Major.YY.Mdd.Build (build number persisted in Versions\build.txt).

Tests

cd test
TestFileVersion.cmd       # Verifies built binary version info
TestAhkNotepad3.cmd       # AutoHotkey-based GUI tests (requires AutoHotkey)

CI

GitHub Actions (.github/workflows/build.yml) builds all four platforms (Win32, x64, x64_AVX2, ARM64) in Release on windows-2022 runners, triggered on push/PR to master.

Architecture

Core Modules (src\)

File	Purpose
Notepad3.c/h	Entry point (wWinMain), window procedure (MainWndProc), global state structs (Globals, Settings, Settings2, Flags, Paths)
Edit.c/h	Text manipulation: find/replace (Oniguruma regex), encoding conversion, clipboard, indentation, sorting, bookmarks, folding, auto-complete
Styles.c/h	Scintilla styling, lexer selection, theme management, margin configuration
Dialogs.c/h	All dialog boxes, DPI-aware UI interactions, window placement
Config/Config.cpp/h	INI file management, settings loading/saving, MRU list
Encoding.c/h	Encoding detection and conversion (integrates uchardet)
SciCall.h	Type-safe inline wrappers for Scintilla direct function calls (avoids SendMessage overhead)
DynStrg.c/h	Custom dynamic wide-string type (HSTRINGW) with automatic buffer management
PathLib.c/h	Path manipulation via opaque HPATHL handle
TypeDefs.h	Core type definitions (DocPos, DocLn, cpi_enc_t), Windows version targeting, compiler macros
MuiLanguage.c/h	Multi-language UI support, language DLL loading

Window Hierarchy

MainWndProc (Notepad3.c)
  +-- Scintilla Edit Control (hwndEdit / IDC_EDIT)
  +-- Toolbar (via Rebar control)
  +-- Status Bar (16 configurable fields)

Vendored Dependencies

Directory	Library	Purpose
scintilla\	Scintilla 5.5.8	Editor component (NP3 patches in np3_patches\, docs in doc\)
lexilla\	Lexilla 5.4.6	Syntax highlighting (NP3 patches in np3_patches\, docs in doc\)
scintilla\oniguruma\	Oniguruma	Regex engine for find/replace
src\uchardet\	uchardet	Mozilla encoding detection
src\tinyexpr\ / src\tinyexprcpp\	TinyExpr	Expression evaluator (statusbar)
src\uthash\	uthash	Hash table / dynamic array macros
src\crypto\	Rijndael/SHA-256	AES-256 encryption
Boost (via vcpkg.json)	Boost Regex & IOStreams	Used by grepWinNP3

Syntax Lexers (src\StyleLexers\)

50+ languages, each in a styleLexXXX.c file. All follow the EDITLEXER struct pattern from EditLexer.h:

EDITLEXER lexXXX = {
    SCLEX_XXX,          // Scintilla lexer ID
    "lexerName",        // Lexilla lexer name (case-sensitive)
    IDS_LEX_XXX_STR,    // Resource string ID
    L"Config Name",     // INI section name
    L"ext1; ext2",      // Default file extensions
    L"",                // Extension buffer (runtime)
    &KeyWords_XXX,      // Keyword lists
    { /* EDITSTYLE array */ }
};

To add a new lexer: create styleLexNEW.c, define the EDITLEXER struct, register in Styles.c lexer array, add localization string IDs to resource files.

Localization (language\)

Resource-based MUI system with 27+ locales. Each locale has a np3_LANG_COUNTRY\ directory with .rc files. Language packs are built as separate DLLs (separate projects in the solution).

Configuration / Portable Design

• INI file alongside executable (Notepad3.ini), no registry usage
• No auto-creation: runs with defaults if no INI exists; user explicitly creates via "Save Settings Now"
• Admin redirect: Notepad3.ini=<path> in [Notepad3] section redirects to per-user path (up to 2 levels)
• Key paths: Paths.IniFile (active writable INI), Paths.IniFileDefault (fallback for recovery)
• INI init flow: FindIniFile() -> TestIniFile() -> CreateIniFile() -> LoadSettings()
• MiniPath follows the same portable INI and admin-redirect pattern (minipath\src\Config.cpp). Redirect targets are auto-created via CreateIniFileEx().

DarkMode (src\DarkMode\)

Windows 10/11 dark mode via IAT (Import Address Table) hooks. Includes stub DLLs for uxtheme and user32.

Code Conventions

Formatting

• LLVM-based .clang-format in src\ — 4-space indentation, Stroustrup brace style, left-aligned pointers, no column limit, no include sorting
• .editorconfig enforces UTF-8/CRLF for source, 4-space indent for C/C++; Lexilla code uses tabs (preserved from upstream)
• String safety via strsafe.h throughout; deprecated string functions are disabled

Type Conventions

• DocPos / DocPosU / DocLn for Scintilla document positions and line numbers (not raw int)
• cpi_enc_t for encoding identifiers
• HSTRINGW and HPATHL (opaque handle types) instead of raw WCHAR* buffers
• NOMINMAX is defined globally — use min()/max() macros or typed equivalents

Scintilla Interaction

Always use SciCall.h wrappers (e.g. SciCall_GetTextLength()) instead of raw SendMessage(hwnd, SCI_XXX, ...). Add missing wrappers to SciCall.h if needed.

Wrapper macros follow the naming DeclareSciCall{V|R}{0|01|1|2}:

• V = void return, R = has return value
• 0 = no params, 1 = one param (wParam), 2 = two params, 01 = lParam only (wParam=0)
• The msg argument is the suffix after SCI_ (e.g. UNDO for SCI_UNDO)

DeclareSciCallV0(Undo, UNDO);                                            // SciCall_Undo()
DeclareSciCallR0(GetTextLength, GETTEXTLENGTH, DocPos);                  // DocPos SciCall_GetTextLength()
DeclareSciCallV1(SetTechnology, SETTECHNOLOGY, int, technology);         // SciCall_SetTechnology(int)
DeclareSciCallR1(SupportsFeature, SUPPORTSFEATURE, bool, int, feature);  // bool SciCall_SupportsFeature(int)

Global State

Application state is centralized in global structs (Globals, Settings, Settings2, Flags, Paths) defined in Notepad3.c. Access these through their defined interfaces rather than adding new globals.

Undo/Redo Transactions

Use _BEGIN_UNDO_ACTION_ / _END_UNDO_ACTION_ macros (defined in Notepad3.h) to group Scintilla operations into single undo steps. These also handle notification limiting during bulk edits.