initial import

8 files changed, 705 insertions, 0 deletions

diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..e69de29
--- /dev/null
+++ b/.gitignore
diff --git a/LICENSE b/LICENSE
new file mode 100644
index 0000000..d402fb6
--- /dev/null
+++ b/LICENSE
@@ -0,0 +1,201 @@
+                                 Apache License
+                           Version 2.0, January 2004
+                        http://www.apache.org/licenses/
+
+   TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION
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+   1. Definitions.
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+      the terms of any separate license agreement you may have executed
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+   6. Trademarks. This License does not grant permission to use the trade
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+   7. Disclaimer of Warranty. Unless required by applicable law or
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+      Contributor provides its Contributions) on an "AS IS" BASIS,
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+
+   END OF TERMS AND CONDITIONS
+
+   APPENDIX: How to apply the Apache License to your work.
+
+      To apply the Apache License to your work, attach the following
+      boilerplate notice, with the fields enclosed by brackets "[]"
+      replaced with your own identifying information. (Don't include
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+   Copyright 2019 Bryan Frimin
+
+   Licensed under the Apache License, Version 2.0 (the "License");
+   you may not use this file except in compliance with the License.
+   You may obtain a copy of the License at
+
+       http://www.apache.org/licenses/LICENSE-2.0
+
+   Unless required by applicable law or agreed to in writing, software
+   distributed under the License is distributed on an "AS IS" BASIS,
+   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+   See the License for the specific language governing permissions and
+   limitations under the License.
diff --git a/README.md b/README.md
new file mode 100644
index 0000000..87ce8f8
--- /dev/null
+++ b/README.md
@@ -0,0 +1 @@
+# rb-cmdline
diff --git a/examples/arguments b/examples/arguments
new file mode 100755
index 0000000..a3f1220
--- /dev/null
+++ b/examples/arguments
@@ -0,0 +1,14 @@
+#!/usr/bin/env ruby
+
+require("rb-cmdline")
+
+cmd = Cmdline.new
+cmd.add_argument("foo", "the first argument")
+cmd.add_argument("bar", "the second argument")
+cmd.add_trailing_arguments("name", "a trailing argument")
+
+cmd.parse(Cmdline.argv)
+
+printf("foo: %s\n", cmd.argument_value("foo"))
+printf("bar: %s\n", cmd.argument_value("bar"))
+printf("names: %s\n", cmd.trailing_arguments_values("name"))
diff --git a/examples/commands b/examples/commands
new file mode 100755
index 0000000..ca643bf
--- /dev/null
+++ b/examples/commands
@@ -0,0 +1,29 @@
+#!/usr/bin/env ruby
+
+require("rb-cmdline")
+
+cmd = Cmdline.new
+
+cmd.add_command("foo", "subcommand 1")
+cmd.add_command("bar", "subcommand 2")
+
+cmd.parse(Cmdline.argv)
+
+commands = {
+  "foo" => -> (args) {
+    printf("running command \"foo\" with arguments %s\n", args[1..])
+  },
+  "bar" => -> (args) {
+    cmd = CLI.new
+    cmd.add_option("n", "", "value", "an example value")
+    cmd.parse(args)
+
+    printf("running command \"bar\" with arguments %s\n", args[1..])
+
+    if cmd.is_option_set("n")
+      printf("n: %s\n", cmd.option_value("n"))
+    end
+  }
+}
+
+commands[cmd.command_name].call(cmd.command_name_and_arguments)
diff --git a/examples/minimal b/examples/minimal
new file mode 100755
index 0000000..7ec826c
--- /dev/null
+++ b/examples/minimal
@@ -0,0 +1,4 @@
+#!/usr/bin/env ruby
+
+cmd = Cmdline.new
+cmd.parse(Cmdline.argv)
diff --git a/examples/options b/examples/options
new file mode 100755
index 0000000..87878db
--- /dev/null
+++ b/examples/options
@@ -0,0 +1,23 @@
+#!/usr/bin/env ruby
+
+require("rb-cmdline")
+
+cmd = Cmdline.new
+cmd.add_option("a", "option-a", "value", "a simple option")
+cmd.set_option_default("a", "42")
+cmd.add_option("b", "", "value", "an short option")
+cmd.add_option("", "option-c", "value", "a long option")
+cmd.add_flag("d", "flag-d", "a simple flag")
+cmd.parse(Cmdline.argv)
+
+printf("a: %s\n", cmd.option_value("a"))
+
+if cmd.is_option_set("b")
+  printf("b: %s\n", cmd.option_value("b"))
+end
+
+if cmd.is_option_set("option-c")
+  printf("option-c: %s\n", cmd.option_value("option-c"))
+end
+
+printf("d: %s\n", cmd.is_option_set("d"))
diff --git a/lib/cmdline.rb b/lib/cmdline.rb
new file mode 100644
index 0000000..780630b
--- /dev/null
+++ b/lib/cmdline.rb
@@ -0,0 +1,433 @@
+# Copyright 2019 Bryan Frimin
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#   http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+module Cmdline
+  Option = Struct.new(
+    :short_name,
+    :long_name,
+    :value_string,
+    :description,
+    :default,
+    :set,
+    :value,
+    keyword_init: true
+  )
+
+  class Option
+    def initialize(*)
+      super
+      self.short_name ||= ""
+      self.long_name ||= ""
+      self.value_string ||= ""
+      self.description ||= ""
+      self.default ||= ""
+      self.set ||= false
+      self.value ||= ""
+    end
+
+    def sort_key
+      return short_name unless short_name.empty?
+      return long_name unless long_name.empty?
+      ""
+    end
+  end
+
+  Argument = Struct.new(
+    :name,
+    :description,
+    :trailing,
+    :value,
+    :trailing_values,
+    keyword_init: true
+  )
+
+  class Argument
+    def initialize(*)
+      super
+      self.name ||= ""
+      self.description ||= ""
+      self.trailing ||= false
+      self.value ||= ""
+      self.trailing_values ||= []
+    end
+  end
+
+  Command = Struct.new(
+    :name,
+    :description,
+    keyword_init: true
+  )
+
+  class Command
+    def initialize(*)
+      super
+      self.name ||= ""
+      self.description ||= ""
+    end
+  end
+
+  CmdLine = Struct.new(
+    :options,
+    :arguments,
+    :commands,
+    :command,
+    :command_arguments,
+    :program_name,
+    keyword_init: true
+  )
+
+  class CmdLine
+    def initialize(*)
+      super
+      self.options ||= {}
+      self.commands ||= {}
+      self.command ||= ""
+      self.arguments ||= []
+      self.command_arguments ||= []
+      self.program_name ||= ""
+    end
+
+    def add_flag(short, long, description)
+      option = Option.new(
+        short_name: short.to_s,
+        long_name: long.to_s,
+        value_string: "",
+        description: description.to_s
+      )
+
+      addopt(option)
+    end
+
+    def add_option(short, long, value, description)
+      option = Option.new(
+        short_name: short.to_s,
+        long_name: long.to_s,
+        value_string: value.to_s,
+        description: description.to_s
+      )
+
+      addopt(option)
+    end
+
+    def set_option_default(name, value)
+      option = self.options[name]
+      raise(ArgumentError, "unknown option") if option.nil?
+      raise(ArgumentError, "flags cannot have a default value") if option.value_string.empty?
+
+      option.default = value
+    end
+
+    def add_argument(name, description)
+      argument = Argument.new(
+        name: name.to_s,
+        description: description.to_s
+      )
+
+      addarg(argument)
+    end
+
+    def add_trailing_arguments(name, description)
+      argument = Argument.new(
+        name: name.to_s,
+        description: description.to_s,
+        trailing: true
+      )
+
+      addarg(argument)
+    end
+
+    def add_command(name, description)
+      if self.arguments.size.zero?
+        add_argument("command", "the command to execute")
+      elsif self.arguments.first.name != "command"
+        raise(ArgumentError, "cannot have both arguments and commands")
+      end
+
+      cmd = Command.new(
+        name: name.to_s,
+        description: description.to_s
+      )
+
+      self.commands[cmd.name] = cmd
+    end
+
+    def die(format, *args)
+      msg = sprintf(format, *args)
+      STDERR.puts("error: #{msg}")
+      exit(1)
+    end
+
+    def parse(args)
+      die("empty argument array") if args.size == 0
+
+      self.program_name = args.shift
+
+      while args.size > 0
+        arg = args.first
+
+        if arg == "--"
+          args.shift
+          break
+        end
+
+        is_short = arg.size == 2 && arg[0] == "-" && arg[1] != "-"
+        is_long = arg.size > 2 && arg[0,2] == "--"
+
+        if is_short || is_long
+          key = if is_short
+                  arg[1,2]
+                else
+                  arg[2..]
+                end
+
+          opt = self.options[key]
+          die("unknown option \"%s\"", key) if opt.nil?
+
+          opt.set = true
+
+          if opt.value_string.empty?
+            args = args[1..]
+          else
+            die("missing value for option \"%s\"", key) if args.size < 2
+            opt.value = args[1]
+            args = args[2..]
+          end
+        else
+          break
+        end
+      end
+
+      if self.arguments.size > 0 && !is_option_set("help")
+        last = self.arguments.last
+
+        min = self.arguments.size
+        min -= 1 if last.trailing
+
+        die("missing argument(s)") if args.size < min
+
+        min.times do |i|
+          self.arguments[i].value = args[i]
+        end
+        args = args[min..]
+
+        if last.trailing
+          last.trailing_values = args
+          args = args[args.size..]
+        end
+      end
+
+      if self.commands.size > 0
+        self.command = self.arguments.first.value
+        self.command_arguments = args
+      end
+
+      if !is_option_set("help")
+        if self.commands.size > 0
+          cmd = self.commands[self.command]
+          if cmd.nil?
+            die("unknown command \"%s\"", self.command)
+          end
+        elsif args.size > 0
+          die("invalid extra argument(s)")
+        end
+      end
+
+      if is_option_set("help")
+        print_usage
+        exit(0)
+      end
+    end
+
+    def print_usage
+      usage = sprintf("Usage: %s OPTIONS", self.program_name)
+      if self.arguments.size > 0
+        self.arguments.each do |arg|
+          if arg.trailing
+            usage << sprintf(" [<%s> ...]", arg.name)
+          else
+            usage << sprintf(" <%s>", arg.name)
+          end
+        end
+      end
+
+      usage << "\n\n"
+
+      opt_strs = {}
+      max_width = 0
+
+      self.options.each do |_, opt|
+        next if opt_strs[opt]
+
+        buf = ""
+
+        if opt.short_name != ""
+          buf << sprintf("-%s", opt.short_name)
+        end
+
+        if opt.long_name != ""
+          if opt.short_name != ""
+            buf << ", "
+          end
+
+          buf << sprintf("--%s", opt.long_name)
+        end
+
+        if opt.value_string != ""
+          buf << sprintf(" <%s>", opt.value_string)
+        end
+
+        opt_strs[opt] = buf
+
+        if buf.size > max_width
+          max_width = buf.size
+        end
+      end
+
+      if self.commands.size > 0
+        self.commands.each do |name, _|
+          max_width = name.size if name.size > max_width
+        end
+      elsif self.arguments.size > 0
+        self.arguments.each do |arg|
+          max_width = arg.name.size if arg.name.size > max_width
+        end
+      end
+
+      # Print options
+      usage << "OPTIONS\n\n"
+
+      opts = []
+      opt_strs.each do |opt, _|
+        opts << opt
+      end
+
+      # TODO: sort options
+
+      opts.each do |opt|
+        usage << sprintf("%-*s  %s", max_width, opt_strs[opt], opt.description)
+        usage << sprintf(" (default: %s)", opt.default) unless opt.default.empty?
+        usage << "\n"
+      end
+
+      if self.commands.size > 0
+        usage << "\nCOMMANDS\n\n"
+        names = []
+        self.commands.each do |name, _|
+          names << name
+        end
+        names.sort!
+
+        names.each do |name|
+          cmd = self.commands[name]
+          usage << sprintf("%-*s  %s\n", max_width, cmd.name, cmd.description)
+        end
+      elsif self.arguments.size > 0
+        usage << "\nARGUMENTS\n\n"
+
+        self.arguments.each do |arg|
+          usage << sprintf("%-*s  %s\n", max_width, arg.name, arg.description)
+        end
+      end
+
+      printf(usage)
+    end
+
+    def is_option_set(name)
+      opt = self.options[name]
+      raise(ArgumentError, "unknown option") if opt.nil?
+      opt.set
+    end
+
+    def option_value(name)
+      opt = self.options[name]
+      raise(ArgumentError, "unknown option") if opt.nil?
+
+      return opt.value if opt.set
+      opt.default
+    end
+
+    def argument_value(name)
+      self.arguments.each do |arg|
+        if arg.name == name
+          return arg.name
+        end
+      end
+      raise(ArgumentError, "unknown argument")
+    end
+
+    def trailing_arguments_values(name)
+      raise(ArgumentError, "empty argument array") if self.arguments.empty?
+      last = self.arguments.last
+      raise(ArgumentError, "no trailing arguments") unless last.trailing
+      last.trailing_values
+    end
+
+    def command_name
+      raise(RuntimeError, "no command defined") if self.commands.empty?
+      self.command
+    end
+
+    def command_arguments_values
+      raise(RuntimeError, "no command defined") if self.commands.empty?
+      self.command_arguments
+    end
+
+    def command_name_and_arguments
+      raise(RuntimeError, "no command defined") if self.commands.empty?
+      [self.command, *self.command_arguments]
+    end
+
+    private
+
+    def addopt(opt)
+      if !opt.short_name.empty?
+        if opt.short_name.size != 1
+          raise(ArgumentError, "option short names must be one character long")
+        end
+
+        self.options[opt.short_name] = opt
+      end
+
+      if !opt.long_name.empty?
+        if opt.long_name.size < 2
+          raise(ArgumentError, "option long names must be at least two characters long")
+        end
+
+        self.options[opt.long_name] = opt
+      end
+    end
+
+    def addarg(arg)
+      raise(ArgumentError, "cannot have both arguments and commands") if self.commands.size > 0
+      if self.arguments.size > 0
+        last = self.arguments.last
+        if last.trailing
+          raise(ArgumentError, "cannot add argument after trailing argument")
+        end
+      end
+
+      self.arguments << arg
+    end
+  end
+
+  def self.new
+    cmd = CmdLine.new
+    cmd.add_flag("h", "help", "print help and exit")
+    cmd
+  end
+
+  def self.argv
+    ARGV.dup.unshift($0)
+  end
+end