NinjaManifest

A Ruby toolkit for parsing and evaluating Ninja build manifest files (build.ninja).

Features:

Parses Ninja build manifest files according to the official Ninja implementation
Evaluates variable expansions and rule bindings
Visitor pattern API for flexible processing
Compact and plain old pure Ruby implementation without external dependencies

Installation

Install the gem and add to the application's Gemfile by executing:

$ bundle add ninja_manifest

If bundler is not being used to manage dependencies, install the gem by executing:

$ gem install ninja_manifest

Basic Usage

require "ninja_manifest"

# Parse and evaluate a build.ninja content
manifest = NinjaManifest.load(<<~NINJA)
cxx = c++
builddir = build

rule cxx
  command = $cxx -c $in -o $out
  description = CXX $out

build $builddir/main.o: cxx src/main.cc
  cxx = clang
NINJA
# Or load from build.ninja file
manifest = NinjaManifest.load_file("build.ninja")

# Access parsed data

manifest.variables             # Variables hash
manifest.variables["cxx"]      # => "c++"

manifest.rules                 # Rules hash
rule = manifest.rules["cxx"]
rule["command"]                # => "$cxx -c $in -o $out"
rule["description"]            # => "CXX $out"

build = manifest.builds.first
build[:outputs][:explicit]     # => ["build/main.o"]
build[:inputs][:explicit]      # => ["src/main.cc"]
build[:vars]["command"]        # => "c++ -c src/main.cc -o build/main.o"
build[:vars]["description"]    # => "CXX build/main.o"

Custom Visitor Usage

require "ninja_manifest"

# Create a custom visitor to process parsed constructs
class MyVisitor < NinjaManifest::Visitor
  def visit_variable(name:, value:)
    puts "Variable: #{name} = #{value}"
  end

  def visit_rule(name:, vars:)
    puts "Rule: #{name} with #{vars.keys.size} attributes"
  end

  def visit_build(rule:, outs:, ins:, vars:, **kwargs)
    puts "Build: #{rule} -> #{outs[:explicit].join(', ')}"
  end
end

visitor = MyVisitor.new
File.open("build.ninja", "r") do |f|
  NinjaManifest::parse(f.read, visitor)
end

Contributing

Bug reports and pull requests are welcome on GitHub at https://github.com/kateinoigakukun/ninja_manifest.

License

The gem is available as open source under the terms of the MIT License.