added maven prompt

[mzellho]

this PR adds a prompt for maven projects

[mzellho]

for the records: slightly improved method using xmllint:

local function get_pom_xml_dir(path)

  -- return parent path for specified entry (either file or directory)
  local function pathname(path)
          local prefix = ""
          local postfix = ""
          local i = path:find("[\\/:][^\\/:]*$")
          if i then
                  prefix = path:sub(1, i-1)

          end
          return prefix
  end

  if not path or path == '.' then path = clink.get_cwd() end

  local parent_path = pathname(path)
  return io.open(path..'\\pom.xml') or (parent_path ~= path and get_pom_xml_dir(parent_path) or nil)
end

-- * Segment object with these properties:
---- * isNeeded: sepcifies whether a segment should be added or not. For example: no Git segment is needed in a non-git folder
---- * text
---- * textColor: Use one of the color constants. Ex: colorWhite
---- * fillColor: Use one of the color constants. Ex: colorBlue
local segment = {
  isNeeded = false,
  text = "",
  textColor = colorWhite,
  fillColor = colorCyan
}

---
-- Sets the properties of the Segment object, and prepares for a segment to be added
---
local function init()
  segment.isNeeded = get_pom_xml_dir()
  if segment.isNeeded then
    local handle = io.popen('xmllint --xpath "//*[local-name()=\'project\']/*[local-name()=\'groupId\']/text()" pom.xml 2>NUL')
	local package_group = handle:read("*a")
	handle:close()
    if package_group == nil or package_group == '' then
		local parent_handle = io.popen('xmllint --xpath "//*[local-name()=\'project\']/*[local-name()=\'parent\']/*[local-name()=\'groupId\']/text()" pom.xml 2>NUL')
		package_group = parent_handle:read("*a")
		parent_handle:close()

		if package_group == nil or package_group == '' then
			package_group = ''
		end
    end

	handle = io.popen('xmllint --xpath "//*[local-name()=\'project\']/*[local-name()=\'artifactId\']/text()" pom.xml 2>NUL')
	local package_artifact = handle:read("*a")
	handle:close()
    if package_artifact == nil or package_artifact == '' then
            package_artifact = ''
    end

	handle = io.popen('xmllint --xpath "//*[local-name()=\'project\']/*[local-name()=\'version\']/text()" pom.xml 2>NUL')
	local package_version = handle:read("*a")
	handle:close()
    if package_version == nil or package_version == '' then
		local parent_handle = io.popen('xmllint --xpath "//*[local-name()=\'project\']/*[local-name()=\'parent\']/*[local-name()=\'version\']/text()" pom.xml 2>NUL')
		package_version = parent_handle:read("*a")
		parent_handle:close()

		if package_version == nil or package_version == '' then
			package_version = ''
		end
    end

    if plc_mvn_mvnSymbol then
      segment.text = " "..mvnSymbol.." "..package_group..":"..package_artifact..":"..package_version.." "
    else
      segment.text = " mvn: "..package_group..":"..package_artifact..":"..package_version.." "
    end 
  end
end 

---
-- Uses the segment properties to add a new segment to the prompt
---
local function addAddonSegment()
  init()
  if segment.isNeeded then 
      addSegment(segment.text, segment.textColor, segment.fillColor)
  end 
end 

-- Register this addon with Clink
clink.prompt.register_filter(addAddonSegment, 60)

[TobiTenno]

this is really cool, but one small inconsistency: plc_mvn_mvnSymbol is your configured symbol name in your code, but plc_npm_npmSymbol is what you added to the config. just might want to fix that.

*edit: one more small thing. it looks like, in sorted poms, that if there's a "parent", that version is being used instead of the actual version