ini.rb

#!/usr/bin/env ruby
RubyVM::InstructionSequence.compile_option = {tailcall_optimization: true, trace_instruction: false}

def parse_line(line)
  case line.strip
  when /^\s*\[\s*(.+?)\s*\]\s*$/   then {section: $1}
  when /^\s*(.+?)\s*=\s*(.+?)\s*$/ then {key: $1, value: $2}
  when /^\s*$/                     then {}
                                   else {error: line}
  end
end

def read(content)
  content.gsub(/\\\s*\n\s*/, "").split("\n")
end

def parse_conf(lines, section="default", res={})
  return res if lines.empty?
  l = parse_line(lines.shift)
  if l[:section]
    parse_conf(lines, l[:section], res)
  elsif (k = l[:key] and v = l[:value])
    res[section] ||= {}
    res[section][k] = v
    parse_conf(lines, section, res)
  elsif l[:error]
    STDERR.puts "Bad line: #{l[:error]}"
    parse_conf(lines, section, res)
  else parse_conf(lines, section, res)
  end
end

require 'minitest/spec'
require 'minitest/autorun'

describe :read do
  it "should drop line wraps" do
    { "abc \\ \n def"  => ["abc def"],
      "abc\\\n def"    => ["abcdef"],
      "abc\\\ndef"     => ["abcdef"],
      "abc\\\n"        => ["abc"],
      "abc\\\n"        => ["abc"],
      "abc\\\ndef\\\n" => ["abcdef"]
    }.each do |k,v|
      read(k).must_equal v
    end
  end
  it "shouldn't drop last line wraps" do
    { "abc\\"        => ["abc\\"],
      "abc\\\ndef\\" => ["abcdef\\"]
    }.each do |k,v|
      read(k).must_equal v
    end
  end
end

describe :parse_line do
  it "should parse key-value pairs" do
    { "k=v"       => {key:"k", value:"v"},
      " k = v "   => {key:"k", value:"v"},
      "k=v=v1=v2" => {key:"k", value:"v=v1=v2"}
    }.each do |k,v|
      parse_line(k).must_equal v
    end
  end
  it "should parse sections" do
    { "[sec]"       => {section:"sec"},
      " [ s e c ] " => {section:"s e c"},
      " [ k = v ] " => {section:"k = v"}
    }.each do |k,v|
      parse_line(k).must_equal v
    end
  end
  it "should detect format errors" do
    { "[sec" => {error:"[sec"},
      "sec]" => {error:"sec]"},
      "k"    => {error:"k"},
      "k = " => {error:"k = "},
      " "    => {}
    }.each do |k,v|
      parse_line(k).must_equal v
    end
  end
end

describe :parse_conf do
  it "should parse complete configs" do
    { ["k=v"]         => {"default" => {"k" => "v"}},
      ["k=v", "x=y"]  => {"default" => {"k" => "v", "x" => "y"}},
      ["k=v", "k=v1"] => {"default" => {"k" => "v1"}},
      ["[s1]", "k=v", "[s2]", "x=y"] => {"s1" => {"k" => "v"}, "s2" => {"x" => "y"}},
      ["[s1]", "k=v", "", "[s2]", "k=w", "", "[s1]", "l=u"] => {"s1" => {"k" => "v", "l" => "u"}, "s2" => {"k" => "w"}},
      ["[s1]", "k=v", "[s2]", "k=w", "[s1]", "k=v1"] => {"s1" => {"k" => "v1"}, "s2" => {"k" => "w"}}
    }.each do |k,v|
      parse_conf(k).must_equal v
    end
  end
end