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Lana Documentation

This is the canonical source of project documentation. README.md, the CLI help text, and the project initializer templates all reference the content in this directory.

Overview
Installation
Project Structure
Commands
Configuration
Build Directives
Build Process
Dependency Management
Command Line Options
Configuration File Format
Troubleshooting
Development

Overview

Lana is a lightweight C++ build system designed for modern C++ development. It provides a simple, fast alternative to complex tools like CMake or Make, emphasizing speed, simplicity, and self-contained project management.

Key features:

Automatic source discovery in src/ directories
Build directives embedded directly in C++ source files for per-file configuration (dependencies, linking, output, flags)
Dependency tracking via #include analysis and timestamp checking
Incremental builds to recompile only changed files
Support for shared libraries, tools/executables, and asset hooks (e.g., GLSL shaders via dependencies)
Simple global configuration via config.ini
Cross-platform (Linux, macOS, Windows) with parallel compilation
No external scripts needed—everything is in your source files

Lana parses // build-directive: comments in your C++ files to handle project-specific details, while config.ini manages globals like compiler flags and paths.

Installation

Prerequisites

V compiler (version 0.3.0 or later)
GCC/G++ (version 7+ recommended)
Standard C++ library
For shader workflows: Vulkan SDK or shaderc (includes glslc)

Building Lana

Clone the repository:

git clone https://github.com/yourusername/lana.git  # Replace with actual repo
cd lana

Build the tool:
```
v . -o lana
```
Make executable (Linux/macOS):
```
chmod +x lana
```
(Optional) Add to PATH:
```
sudo mv lana /usr/local/bin/
```

Project Structure

Lana expects this layout (created by lana init):

project/
├── src/              # Source files (.cpp, .cc, .cxx) with build directives
│   ├── main.cpp      # Example main tool (directives at top)
│   ├── lib/          # Shared library sources
│   │   └── cli.cpp   # Example shared lib (directives at top)
│   ├── tools/        # Tool/executable sources
│   │   └── example_tool.cpp  # Example tool depending on lib/cli
├── include/          # Header files (.h, .hpp)
│   └── cli.h         # Example header
├── build/            # Generated: Object files (*.o), dependencies (*.d)
├── bin/              # Generated: Executables and libs
│   ├── lib/          # Shared libraries (.so/.dll)
│   ├── tools/        # Tool executables
├── config.ini        # Global build configuration
├── README.md         # Project docs (auto-generated with directive examples)
└── .gitignore        # Git ignore file

Build Directives: Add // build-directive: comments at the top of C++ files for per-file settings (see Build Directives).
Auto-Discovery: If no directives, Lana treats files as simple tools using global config.

Commands

Initialize Project

lana init <project_name>

Creates the structure above, including template C++ files with build directives by default (e.g., in src/main.cpp, src/lib/cli.cpp). Includes config.ini, README.md (with directive docs), and examples for shared libs/tools.

Example:

lana init myapp
cd myapp
# Files like src/main.cpp now have directives like:
# // build-directive: unit-name(tools/main)
# // build-directive: out(tools/main)

Build Project

lana build [options]

Compiles sources, processes directives, builds dependency graph, and links outputs. Incremental: only rebuilds changed files.

Example:

lana build -d -v  # Debug build with verbose output (shows directive parsing)

Run Project

lana run [options]

Builds (if needed) and runs the main executable (first tool or project_name from config/directives).

Clean Project

lana clean

Removes build/, bin/, and intermediates.

Help

lana --help

Shows commands, options, and config examples.

Setup (dependencies)

lana setup

Fetches and extracts external dependencies declared in config.ini under [dependencies] sections. Each dependency supports the following keys:

name - logical name for the dependency (required)
url - download URL or git repository (optional)
archive - optional filename to save the downloaded archive under dependencies/tmp
checksum - optional sha256 checksum to verify the archive
extract_to - directory under dependencies/ where files should be extracted or cloned
build_cmds - optional semicolon-separated shell commands to build/install the dependency

Notes:

Only name is required. If url is omitted Lana will skip any download/clone and extraction steps — useful for dependencies generated locally or that only require running project-local commands.
If url points to a git repository (ends with .git), lana setup performs a shallow clone into dependencies/<extract_to>.
For archive URLs lana setup tries curl then wget to download, verifies checksum if provided, and extracts common archive types (.tar.gz, .tar.xz, .zip).
When build_cmds are present they run either inside dependencies/<extract_to> (if available) or in the project root.

Configuration

config.ini handles global settings (overridden by directives for per-file needs). Edit it in your project root.

Basic Configuration

# Project identification
project_name = myapp

# Directory paths (relative to project root)
src_dir = src
build_dir = build
bin_dir = bin

# Build modes (CLI overrides)
debug = true
optimize = false

# Output verbosity
verbose = false

# Compiler settings (global defaults; directives can add/override)
include_dirs = include  # Comma/space-separated
libraries = pthread     # Comma/space-separated (global libs)
cflags = -Wall -Wextra -std=c++17
ldflags = 

# Advanced
parallel_compilation = true
dependencies_dir = dependencies

Configuration Precedence

Command-line options (highest: e.g., -d overrides debug=true)
config.ini
Defaults (e.g., debug=true, compiler=g++)

Directives (in source files) handle per-file overrides (e.g., custom cflags for one unit).

Build Directives

Lana's killer feature: Embed build instructions directly in C++ source files using // build-directive: comments. No separate scripts—keeps projects self-contained.

How It Works

Parsing: lana build scans sources for lines like // build-directive: <type>(<value>).
Processing: Builds a dependency graph; resolves build order, linking, and flags.
Placement: At file top (before code). Multiple per file (one per line).
Fallback: No directives? Auto-discover as simple tool using global config.
Output: Verbose mode (-v) shows parsed units/graph.

Syntax

// build-directive: <type>(<value>)

<type>: Directive name (e.g., unit-name).
<value>: Arguments (comma/space-separated for lists; true/false for bools).

Supported Directives

unit-name(<name>): Unique unit ID (e.g., "lib/cli", "tools/mytool"). Required for custom builds. Defaults to file path if omitted.
depends-units(<unit1>,<unit2>,...): Dependencies (other units). Builds them first.
link(<lib1>,<lib2>,...): Libraries to link (internal or external).
out(<path>): Output relative to bin/ (e.g., "tools/mytool", "lib/mylib"). Defaults to unit name.
cflags(<flag1> <flag2> ...): Per-file compiler flags. Appends to global cflags.
ldflags(<flag1> <flag2> ...): Per-file linker flags.
shared(<true|false>): Build as shared lib (.so/.dll, true) or executable (false).

Examples

Simple Executable (src/main.cpp):

// build-directive: unit-name(tools/main)
// build-directive: depends-units()
// build-directive: link()
// build-directive: out(tools/main)

#include <iostream>

int main() {
    std::cout << "Hello, World!" << std::endl;
    return 0;
}

Shared Library (src/lib/cli.cpp):

// build-directive: unit-name(lib/cli)
// build-directive: depends-units()
// build-directive: link()
// build-directive: out(lib/cli)
// build-directive: shared(true)
// build-directive: cflags(-fPIC)

#include <iostream>
#include "cli.h"

namespace lana {
    void print_help() { std::cout << "CLI help" << std::endl; }
}

Tool Depending on Shared Lib (src/tools/mytool.cpp):

// build-directive: unit-name(tools/mytool)
// build-directive: depends-units(lib/cli)
// build-directive: link(cli.so)
// build-directive: out(tools/mytool)
// build-directive: shared(false)
// build-directive: cflags(-std=c++17)
// build-directive: ldflags(-pthread)

#include <iostream>
#include "cli.h"

int main() {
    lana::print_help();
    return 0;
}

Build Process

Parse Directives: Scans sources for // build-directive:; collects into units/graph.
Source Discovery: Finds .cpp/.cc/.cxx in src_dir (recursive).
Dependency Analysis: Extracts #includes; builds graph from directives/timestamps.
Incremental Check: Recompiles if source/header newer than .o or .d missing.
Compilation: g++ -c each source to .o (uses global + per-file flags).
Linking: Builds shared libs/tools per directives (e.g., g++ -shared for libs).
Dependency Hooks: Executes [dependencies] build commands (use for assets like shaders).

Example Output (lana build -v):

Parsing build directives...
Found directive for unit: lib/cli in src/lib/cli.cpp
Found directive for unit: tools/mytool in src/tools/mytool.cpp
Building dependency graph...
Build order: lib/cli -> tools/mytool
Building unit: lib/cli
Compiling src/lib/cli.cpp -> build/lib/cli.o
Linking shared library: bin/lib/cli.so
Building unit: tools/mytool
Compiling src/tools/mytool.cpp -> build/tools/mytool.o
Linking executable: bin/tools/mytool
Build completed successfully!

Dependency Management

Include Extraction: Parses #include for rebuild triggers (local/system headers).
Directive-Based Deps: depends-units() defines unit graph; link() handles libs.
Timestamp Checks: Rebuild if source/header > .o timestamp.
Generated .d Files: Make-compatible deps (e.g., build/main.o: src/main.cpp include/utils.hpp).
Graph Resolution: Topological sort; warns on cycles.

Command Line Options

Option	Description	Example
`-d, --debug`	Debug mode (`-g -O0`)	`lana build -d`
`-O, --optimize`	Optimized mode (`-O3`)	`lana build -O`
`-v, --verbose`	Show commands/graph	`lana build -v`
`-p, --parallel`	Parallel jobs	`lana build -p`
`-o <name>`	Output name	`lana build -o app`
`-I <dir>`	Include dir	`lana build -I external/`
`-l <lib>`	Link lib	`lana build -l pthread`
`--config <file>`	Custom config	`lana build --config release.ini`
`--shared-lib <name> <source>`	Legacy shared lib	`lana build --shared-lib cli src/lib/cli.cpp`
`--tool <name> <source>`	Legacy tool	`lana build --tool mytool src/tools/mytool.cpp`

Examples:

lana build -d -v -p  # Debug, verbose, parallel
lana run -O           # Optimized run
lana build -I lib/include -l boost -l sqlite3

Configuration File Format

INI-style (config.ini):

# Comments with #
key = value
array_key = val1, val2  # Comma/space-separated

Full Example (config.ini):

[global]
project_name = myapp
src_dir = src
build_dir = build
bin_dir = bin
debug = true
optimize = false
verbose = false
parallel_compilation = true
include_dirs = include,external/include
libraries = pthread,boost_system
cflags = -Wall -Wextra -std=c++17
ldflags = -static

[shared_libs]
name = cli
sources = src/lib/cli.cpp
libraries = 

[tools]
name = main
sources = src/main.cpp
libraries = cli

Troubleshooting

"No source files found": Check src_dir in config; ensure .cpp files exist.
"Failed to parse directive": Verify syntax (e.g., unit-name(lib/cli)); use -v for details.
"Dependency not found": Add missing depends-units() or build order in directives.
Linking errors: Check link() for libs; install dev packages (e.g., sudo apt install libpthread-dev).
Asset build fails: Verify commands in [dependencies] hook scripts.
Permission denied: chmod +x bin/tools/mytool.

Debugging Tips

Verbose Build: lana build -v shows directive parsing, graph, and commands.
Check Graph: Look for "Build order:" in verbose output.
Dependency Files: Inspect build/*.d for include tracking.
Logs: lana build -v > build.log 2>&1.
Clean Rebuild: lana clean && lana build -v.

Development

See the source code structure in the repo. To extend:

Add directives: Update config.BuildDirective and builder.build_from_directives().
New features: Modify config.v for parsing, builder.v for logic.

For contributing, see Gitea (fork, branch, PR).

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