Modul:TemplatePar

--[=[ TemplatePar 2013-06-28 Template parameter utility

• assert
• check
• count
• countNotEmpty
• downcase
• valid
• verify
• TemplatePar()

]=]

-- Module globals local TemplatePar = { } local messagePrefix = "lua-module-TemplatePar-" local l10nDef = {} l10nDef[ "en" ] = {

   badPattern  = "#invoke:TemplatePar * pattern syntax error",
   dupOpt      = "#invoke:TemplatePar * repeated optional parameter",
   dupRule     = "#invoke:TemplatePar * parameter conflict key/pattern",
   empty       = "Error in template * undefined value for mandatory",
   invalid     = "Error in template * invalid parameter",
   invalidPar  = "#invoke:TemplatePar * invalid parameter",
   minmax      = "#invoke:TemplatePar * min > max",
   multiSpell  = "Error in template * multiple spelling of parameter",
   noErrorCat  = "#invoke:TemplatePar * noError and missing category",
   noname      = "#invoke:TemplatePar * missing parameter name",
   tooLong     = "Error in template * parameter too long",
   tooShort    = "Error in template * parameter too short",
   undefined   = "Error in template * mandatory parameter missing",
   unknown     = "Error in template * unknown parameter name",
   unknownRule = "#invoke:TemplatePar * unknown rule"

} l10nDef[ "de" ] = {

   badPattern  = "#invoke:TemplatePar * Syntaxfehler des pattern",
   dupOpt      = "#invoke:TemplatePar * Optionsparameter wiederholt",
   dupRule     = "#invoke:TemplatePar * Parameterkonflikt key/pattern",
   empty       = "Fehler bei Vorlage * Pflichtparameter ohne Wert",
   invalid     = "Fehler bei Vorlage * Parameter ungültig",
   invalidPar  = "#invoke:TemplatePar * Ungültiger Parameter",
   minmax      = "#invoke:TemplatePar * min > max",
   multiSpell  = "Fehler bei Vorlage * Mehrere Parameter-Schreibweisen",
   noErrorCat  = "#invoke:TemplatePar * noError und keine Kategorie",
   noname      = "#invoke:TemplatePar * Parametername nicht angegeben",
   tooLong     = "Fehler bei Vorlage * Parameter zu lang",
   tooShort    = "Fehler bei Vorlage * Parameter zu kurz",
   undefined   = "Fehler bei Vorlage * Pflichtparameter fehlt",
   unknown     = "Fehler bei Vorlage * Parametername unbekannt",
   unknownRule = "#invoke:TemplatePar * Unbekannte Regel"

} local Patterns = {

   [ "ASCII" ]   = "^[ -~]*$",
   [ "ASCII+" ]   = "^[ -~]+$",
   [ "ASCII+1" ]  = "^[!-~]+$",
   [ "n" ]        = "^%-?[0-9]*$",
   [ "n>0" ]      = "^[0-9]*[1-9][0-9]*$",
   [ "N+" ]       = "^%-?[1-9][0-9]*$",
   [ "N>0" ]      = "^[1-9][0-9]*$",
   [ "x" ]        = "^[0-9A-Fa-f]*$",
   [ "x+" ]       = "^[0-9A-Fa-f]+$",
   [ "X" ]        = "^[0-9A-F]*$",
   [ "X+" ]       = "^[0-9A-F]+$",
   [ "0,0" ]      = "^%-?[0-9]*,?[0-9]*$",
   [ "0,0+" ]     = "^%-?[0-9]+,[0-9]+$",
   [ "0,0+?" ]    = "^%-?[0-9]+,?[0-9]*$",
   [ "0.0" ]      = "^%-?[0-9]*%.?[0-9]*$",
   [ "0.0+" ]     = "^%-?[0-9]+%.[0-9]+$",
   [ "0.0+?" ]    = "^%-?[0-9]+%.?[0-9]*$",
   [ ".0+" ]      = "^%-?[0-9]*%.?[0-9]+$",
   [ "ID" ]       = "^[A-Za-z]?[A-Za-z_0-9]*$",
   [ "ID+" ]      = "^[A-Za-z][A-Za-z_0-9]*$",
   [ "ABC" ]      = "^[A-Z]*$",
   [ "ABC+" ]     = "^[A-Z]+$",
   [ "Abc" ]      = "^[A-Z]*[a-z]*$",
   [ "Abc+" ]     = "^[A-Z][a-z]+$",
   [ "abc" ]      = "^[a-z]*$",
   [ "abc+" ]     = "^[a-z]+$",
   [ "aBc+" ]     = "^[a-z]+[A-Z][A-Za-z]*$",
   [ "base64" ]   = "^[A-Za-z0-9%+/]*$",
   [ "base64+" ]  = "^[A-Za-z0-9%+/]+$",
   [ "aa" ]       = "[%a%a].*[%a%a]",
   [ "pagename" ] = string.format( "^[^#<>%%[%%]|{}%s%-s%s]+$",
                                   1, 31, 127 ),
   [ "+" ]        = "%S"

} local patternCJK = false

local function containsCJK( s )

   -- Is any CJK character present?
   -- Precondition:
   --     s  -- string
   -- Postcondition:
   --     Return false iff no CJK present
   -- Uses:
   --     >< patternCJK
   --     mw.ustring.char()
   --     mw.ustring.match()
   local r = false
   if not patternCJK then
       patternCJK = mw.ustring.char( 91,
                                      13312, 45,  40959,
                                     131072, 45, 178207,
                                     93 )
   end
   if mw.ustring.match( s, patternCJK ) then
       r = true
   end
   return r

end -- containsCJK()

local function factory( say )

   -- Retrieve localized message string in content language
   -- Precondition:
   --     say  -- string; message ID
   -- Postcondition:
   --     Return some message string
   -- Uses:
   --     >  messagePrefix
   --     >  l10nDef
   --     mw.language.getContentLanguage()
   --     mw.message.new()
   local c = mw.language.getContentLanguage():getCode()
   local m = mw.message.new( messagePrefix .. say )
   local r = false
   if m:isBlank() then
       local l10n = l10nDef[ c ]
       if not l10n then
           l10n = l10nDef[ "en" ]
       end
       r = l10n[ say ]
   else
       m:inLanguage( c )
       r = m:plain()
   end
   if not r then
       r = "(((".. say .. ")))"
   end
   return r

end -- factory()

local function failsafe( story, scan )

   -- Test for match (possibly user-defined with syntax error)
   -- Precondition:
   --     story  -- string; parameter value
   --     scan   -- string; pattern
   -- Postcondition:
   --     Return nil, if not matching, else non-nil
   -- Uses:
   --     mw.ustring.match()
   return  mw.ustring.match( story, scan )

end -- failsafe()

local function failure( spec, suspect, options )

   -- Submit localized error message
   -- Precondition:
   --     spec     -- string; message ID
   --     suspect  -- string or nil; additional information
   --     options  -- table or nil; optional details
   --                 options.template
   -- Postcondition:
   --     Return string
   -- Uses:
   --     factory()
   local r = factory( spec )
   if type( options ) == "table" then
       if type( options.template ) == "string" then
           if #options.template > 0 then
               r = r .. " (" .. options.template .. ")"
           end
       end
   end
   if suspect then
       r = r .. ": " .. suspect
   end
   return r

end -- failure()

local function fault( store, key )

   -- Add key to collection string and insert separator
   -- Precondition:
   --     store  -- string or nil or false; collection string
   --     key    -- string or number; to be appended
   -- Postcondition:
   --     Return string; extended
   local r
   local s
   if type( key ) == "number" then
       s = tostring( key )
   else
       s = key
   end
   if store then
       r = store .. "; " .. s
   else
       r = s
   end
   return r

end -- fault()

local function fed( haystack, needle )

   -- Find needle in haystack map
   -- Precondition:
   --     haystack  -- table; map of key values
   --     needle    -- any; identifier
   -- Postcondition:
   --     Return true iff found
   local k, v
   for k, v in pairs( haystack ) do
       if k == needle then
           return true
       end
   end -- for k, v
   return false

end -- fed()

local function fetch( light, options )

   -- Return regular table with all parameters
   -- Precondition:
   --     light    -- true: template transclusion;  false: #invoke
   --     options  -- table; optional details
   --                 options.low
   -- Postcondition:
   --     Return table; whitespace-only values as false
   -- Uses:
   --     TemplatePar.downcase()
   --     mw.getCurrentFrame()
   --     frame:getParent()
   local g, k, v
   local r = { }
   if options.low then
       g = TemplatePar.downcase( options )
   else
       g = mw.getCurrentFrame()
       if light then
           g = g:getParent()
       end
       g = g.args
   end
   if type( g ) == "table"  then
       r = { }
       for k, v in pairs( g ) do
           if type( v ) == "string" then
               if v:match( "^%s*$" ) then
                   v = false
               end
           else
               v = false
           end
           if type( k ) == "number" then
               k = tostring( k )
           end
           r[ k ] = v
       end -- for k, v
   else
       r = g
   end
   return r

end -- fetch()

local function fill( specified )

   -- Split requirement string separated by '='
   -- Precondition:
   --     specified  -- string or nil; requested parameter set
   -- Postcondition:
   --     Return sequence table
   -- Uses:
   --     mw.text.split()
   local r
   if specified then
       local i, s
       r = mw.text.split( specified, "%s*=%s*" )
       for i = #r, 1, -1 do
           s = r[ i ]
           if #s == 0 then
               table.remove( r, i )
           end
       end -- for i, -1
   else
       r = { }
   end
   return r

end -- fill()

local function finalize( submit, options )

   -- Finalize message
   -- Precondition:
   --     submit   -- string or false or nil; non-empty error message
   --     options  -- table or nil; optional details
   --                 options.noError
   --                 options.cat
   --                 options.template
   -- Postcondition:
   --     Return string or false
   -- Uses:
   --     factory()
   local r = false
   if submit then
       local opt, s
       if type( options ) == "table" then
           opt = options
       else
           opt = { }
       end
       if opt.noError then
           if not opt.cat then
               r = submit .. " " .. factory( "noErrorCat" )
           end
       else
           r = submit
       end
       if r then
           r = ""
       end
       s = opt.cat
       if type( s ) == "string" then
           if not r then
              r = ""
           end
           if s:find( "@@@" ) then
               if type( opt.template ) == "string" then
                   s = s:gsub( "@@@", opt.template )
               end
           end
           r = r .. ""
       end
   end
   return r

end -- finalize()

local function finder( haystack, needle )

   -- Find needle in haystack sequence
   -- Precondition:
   --     haystack  -- table; sequence of key names, downcased if low
   --     needle    -- any; key name
   -- Postcondition:
   --     Return true iff found
   local i
   for i = 1, #haystack do
       if haystack[ i ] == needle then
           return true
       end
   end -- for i
   return false

end -- finder()

local function fix( valid, duty, got, options )

   -- Perform parameter analysis
   -- Precondition:
   --     valid    -- table; unique sequence of known parameters
   --     duty     -- table; sequence of mandatory parameters
   --     got      -- table; sequence of current parameters
   --     options  -- table or nil; optional details
   -- Postcondition:
   --     Return string as configured; empty if valid
   -- Uses:
   --     finder()
   --     fault()
   --     failure()
   --     fed()
   local k, v
   local r = false
   for k, v in pairs( got ) do
       if not finder( valid, k ) then
           r = fault( r, k )
       end
   end -- for k, v
   if r then
       r = failure( "unknown", r, options )
   else -- all names valid
       local i, s
       for i = 1, #duty do
           s = duty[ i ]
           if not fed( got, s ) then
               r = fault( r, s )
           end
       end -- for i
       if r then
           r = failure( "undefined", r, options )
       else -- all mandatory present
           for i = 1, #duty do
               s = duty[ i ]
               if not got[ s ] then
                   r = fault( r, s )
               end
           end -- for i
           if r then
               r = failure( "empty", r, options )
           end
       end
   end
   return r

end -- fix()

local function flat( collection, options )

   -- Return all table elements with downcased string
   -- Precondition:
   --     collection  -- table; k=v pairs
   --     options     -- table or nil; optional messaging details
   -- Postcondition:
   --     Return table, may be empty; or string with error message.
   -- Uses:
   --     mw.ustring.lower()
   --     fault()
   --     failure()
   local k, v
   local r = { }
   local e = false
   for k, v in pairs( collection ) do
       if type ( k ) == "string" then
           k = mw.ustring.lower( k )
           if r[ k ] then
               e = fault( e, k )
           end
       end
       r[ k ] = v
   end -- for k, v
   if e then
       r = failure( "multiSpell", e, options )
   end
   return r

end -- flat()

local function fold( options )

   -- Merge two tables, create new sequence if both not empty
   -- Precondition:
   --     options  -- table; details
   --                 options.mandatory   sequence to keep unchanged
   --                 options.optional    sequence to be appended
   --                 options.low         downcased expected
   -- Postcondition:
   --     Return merged table, or message string if error
   -- Uses:
   --     finder()
   --     fault()
   --     failure()
   --     flat()
   local i, e, r, s
   local base   = options.mandatory
   local extend = options.optional
   if #base == 0 then
       if #extend == 0 then
           r = { }
       else
           r = extend
       end
   else
       if #extend == 0 then
           r = base
       else
           e = false
           for i = 1, #extend do
               s = extend[ i ]
               if finder( base, s ) then
                   e = fault( e, s )
               end
           end -- for i
           if e then
               r = failure( "dupOpt", e, options )
           else
               r = { }
               for i = 1, #base do
                   table.insert( r, base[ i ] )
               end -- for i
               for i = 1, #extend do
                   table.insert( r, extend[ i ] )
               end -- for i
           end
       end
   end
   if options.low  and  type( r ) == "table" then
       r = flat( r, options )
   end
   return r

end -- fold()

local function form( light, options )

   -- Run parameter analysis on current environment
   -- Precondition:
   --     light    -- true: template transclusion;  false: #invoke
   --     options  -- table or nil; optional details
   --                 options.mandatory
   --                 options.optional
   -- Postcondition:
   --     Return string with error message as configured;
   --            false if valid
   -- Uses:
   --     fold()
   --     failure()
   --     fetch()
   --     fix()
   --     finalize()
   local duty, r
   if type( options ) == "table" then
       if type( options.mandatory ) ~= "table" then
           options.mandatory = { }
       end
       duty = options.mandatory
       if type( options.optional ) ~= "table" then
           options.optional = { }
       end
       r = fold( options )
   else
       options = { }
       duty    = { }
       r       = { }
   end
   if type( r ) == "table" then
       local got = fetch( light, options )
       if type( got ) == "table" then
           r = fix( r, duty, got, options )
       else
           r = got
       end
   end
   return finalize( r, options )

end -- form()

local function format( analyze, options )

   -- Check validity of a value
   -- Precondition:
   --     analyze  -- string to be analyzed
   --     options  -- table or nil; optional details
   --                 options.pattern
   --                 options.key
   --                 options.say
   --                 options.min
   --                 options.max
   -- Postcondition:
   --     Return string with error message as configured;
   --            false if valid or no answer permitted
   -- Uses:
   --     >  Patterns
   --     failure()
   --     mw.text.trim()
   --     failsafe()
   --     containsCJK()
   local r    = false
   local s    = false
   local show = nil
   local scan = false
   if type( options.pattern ) == "string" then
       if options.key then
           r = failure( "dupRule", false, options )
       else
           scan = options.pattern
       end
   else
       if type( options.key ) == "string" then
           s = mw.text.trim( options.key )
       else
           s = "+"
       end
       scan = Patterns[ s ]
       if type( scan ) == "string" then
           if s == "n" or s == "0,0" or s == "0.0" then
               if not analyze:match( "[0-9]" ) then
                   scan = false
                   if options.say then
                       show = "'" .. options.say .. "'"
                   end
                   r = failure( "invalid", show, options )
               end
           end
       else
           r = failure( "unknownRule", s, options )
       end
   end
   if scan then
       local legal, got = pcall( failsafe, analyze, scan )
       if legal then
           if not got then
               if s == "aa" then
                   got = containsCJK( analyze )
               end
               if not got then
                   if options.say then
                       show = "'" .. options.say .. "'"
                   end
                   r = failure( "invalid", show, options )
               end
           end
       else
           r = failure( "badPattern",
                        scan .. " *** " .. got,
                        options )
       end
   end
   if options.min  and  not r then
       if type( options.min ) == "number" then
           if type( options.max ) == "number" then
               if options.max < options.min then
                   r = failure( "minmax",
                                tostring( options.min )
                                .. " > " ..
                                tostring( options.max ),
                                options )
               end
           end
           if #analyze < options.min  and  not r then
               show = " <" .. options.min
               if options.say then
                   show = show .. " '" .. options.say .. "'"
               end
               r = failure( "tooShort", show, options )
           end
       else
           r = failure( "invalidPar", "min", options )
       end
   end
   if options.max  and  not r then
       if type( options.max ) == "number" then
           if #analyze > options.max then
               show = " >" .. options.max
               if options.say then
                   show = show .. " '" .. options.say .. "'"
               end
               r = failure( "tooLong", show, options )
           end
       else
           r = failure( "invalidPar", "max", options )
       end
   end
   return r

end -- format()

local function formatted( assignment, access, options )

   -- Check validity of one particular parameter in a collection
   -- Precondition:
   --     assignment  -- collection
   --     access      -- id of parameter in collection
   --     options     -- table or nil; optional details
   -- Postcondition:
   --     Return string with error message as configured;
   --            false if valid or no answer permitted
   -- Uses:
   --     >  Patterns
   --     failure()
   --     mw.text.trim()
   --     format()
   --     failure()
   local r = false
   if type( assignment ) == "table" then
       local story = assignment.args[ access ]
       if type( story ) == "string" then
           if type( options ) ~= "table" then
               options = { }
           end
           options.say = access
           r = format( story, options )
       else
           r = failure( "invalid", access, options )
       end
   end
   return r

end -- formatted()

local function furnish( frame, action )

   -- Prepare #invoke evaluation of .assert() or .valid()
   -- Precondition:
   --     frame    -- object; #invoke environment
   --     action   -- "assert" or "valid"
   -- Postcondition:
   --     Return string with error message or ""
   -- Uses:
   --     form()
   --     mw.text.trim()
   --     TemplatePar.assert()
   --     TemplatePar.valid()
   local options = { mandatory = { "1" },
                     optional  = { "2",
                                   "cat",
                                   "low",
                                   "max",
                                   "min",
                                   "noError",
                                   "template" },
                     template  = "#invoke:TemplatePar|".. action .. "|"
                   }
   local r       = form( false, options )
   if not r then
       local s = mw.text.trim( frame.args[ 2 ] )
       options = { cat      = frame.args.cat,
                   low      = frame.args.low,
                   noError  = frame.args.noError,
                   template = frame.args.template
                 }
       if type( s ) == "string" then
           local sub = s:match( "^/(.*%S)/$" )
           if type( sub ) == "string" then
               sub = sub:gsub( "%%!", "|" )
               sub = sub:gsub( "%%%(%(", "{{" )
               sub = sub:gsub( "%%%)%)", "}}" )
               options.pattern = sub
           else
               options.key = s
           end
       end
       if type( frame.args.min ) == "string" then
           s = frame.args.min:match( "^%s*([0-9]+)%s*$" )
           if s then
               options.min = tonumber( s )
           else
               r = failure( "invalidPar",
                            "min=" .. frame.args.min,
                            options )
           end
       end
       if type( frame.args.max ) == "string" then
           s = frame.args.max:match( "^%s*([1-9][0-9]*)%s*$" )
           if s then
               options.max = tonumber( s )
           else
               r = failure( "invalidPar",
                            "max=" .. frame.args.max,
                            options )
           end
       end
       if r then
           r = finalize( r, options )
       else
           s = frame.args[ 1 ] or ""
           r = tonumber( s )
           if ( r ) then
               s = r
           end
           r = TemplatePar[ action ]( s, options )
       end
   end
   return r or ""

end -- furnish()

TemplatePar.assert = function ( analyze, append, options )

   -- Perform parameter analysis on a single string
   -- Precondition:
   --     analyze  -- string to be analyzed
   --     append   -- string: append error message, prepending 

   --                 false or nil: throw error with message
   --     options  -- table; optional details
   -- Postcondition:
   --     Return string with error message as configured;
   --            false if valid
   -- Uses:
   --     format()
   local r = format( analyze, options )
   if ( r ) then
       if ( type( append ) == "string" ) then
           if ( append ~= "" ) then
               r = append .. "
" .. r
           end
       else
           error( r, 0 )
       end
   end
   return r

end -- TemplatePar.assert()

TemplatePar.check = function ( options )

   -- Run parameter analysis on current template environment
   -- Precondition:
   --     options  -- table or nil; optional details
   --                 options.mandatory
   --                 options.optional
   -- Postcondition:
   --     Return string with error message as configured;
   --            false if valid
   -- Uses:
   --     form()
   return form( true, options )

end -- TemplatePar.check()

TemplatePar.count = function ()

   -- Return number of template parameters
   -- Postcondition:
   --     Return number, starting at 0
   -- Uses:
   --     mw.getCurrentFrame()
   --     frame:getParent()
   local k, v
   local r = 0
   local t = mw.getCurrentFrame():getParent()
   local o = t.args
   for k, v in pairs( o ) do
       r = r + 1
   end -- for k, v
   return r

end -- TemplatePar.count()

TemplatePar.countNotEmpty = function ()

   -- Return number of template parameters with more than whitespace
   -- Postcondition:
   --     Return number, starting at 0
   -- Uses:
   --     mw.getCurrentFrame()
   --     frame:getParent()
   local k, v
   local r = 0
   local t = mw.getCurrentFrame():getParent()
   local o = t.args
   for k, v in pairs( o ) do
       if not v:match( "^%s*$" ) then
           r = r + 1
       end
   end -- for k, v
   return r

end -- TemplatePar.countNotEmpty()

TemplatePar.downcase = function ( options )

   -- Return all template parameters with downcased name
   -- Precondition:
   --     options  -- table or nil; optional messaging details
   -- Postcondition:
   --     Return table, may be empty; or string with error message.
   -- Uses:
   --     mw.getCurrentFrame()
   --     frame:getParent()
   --     mw.ustring.lower()
   --     fault()
   --     failure()
   local t = mw.getCurrentFrame():getParent()
   return flat( t.args, options )

end -- TemplatePar.downcase()

TemplatePar.valid = function ( access, options )

   -- Check validity of one particular template parameter
   -- Precondition:
   --     access   -- id of parameter in template transclusion
   --     options  -- table or nil; optional details
   -- Postcondition:
   --     Return string with error message as configured;
   --            false if valid or no answer permitted
   -- Uses:
   --     mw.text.trim()
   --     TemplatePar.downcase()
   --     mw.getCurrentFrame()
   --     frame:getParent()
   --     formatted()
   --     failure()
   --     finalize()
   local r
   if type( access ) == "string" then
       r = mw.text.trim( access )
       if #r == 0 then
           r = false
       end
   end
   if r then
       local params
       if type( options ) ~= "table" then
           options = { }
       end
       if options.low then
           params = TemplatePar.downcase( options )
       else
           params = mw.getCurrentFrame():getParent()
       end
       r = formatted( params, access, options )
   else
       r = failure( "noname", false, options )
   end
   return finalize( r, options )

end -- TemplatePar.valid()

TemplatePar.verify = function ( options )

   -- Perform #invoke parameter analysis
   -- Precondition:
   --     options  -- table or nil; optional details
   -- Postcondition:
   --     Return string with error message as configured;
   --            false if valid
   -- Uses:
   --     form()
   return form( false, options )

end -- TemplatePar.verify()

-- Provide external access local p = {}

function p.assert( frame )

   -- Perform parameter analysis on some single string
   -- Precondition:
   --     frame  -- object; #invoke environment
   -- Postcondition:
   --     Return string with error message or ""
   -- Uses:
   --     furnish()
   return furnish( frame, "assert" )

end -- .assert()

function p.check( frame )

   -- Check validity of template parameters
   -- Precondition:
   --     frame  -- object; #invoke environment
   -- Postcondition:
   --     Return string with error message or ""
   -- Uses:
   --     form()
   --     fill()
   local options = { optional  = { "all",
                                   "opt",
                                   "cat",
                                   "low",
                                   "noError",
                                   "template" },
                     template  = "#invoke:TemplatePar|check|"
                   }
   local r = form( false, options )
   if not r then
       options = { mandatory = fill( frame.args.all ),
                   optional  = fill( frame.args.opt ),
                   cat       = frame.args.cat,
                   low       = frame.args.low,
                   noError   = frame.args.noError,
                   template  = frame.args.template
                 }
       r       = form( true, options )
   end
   return r or ""

end -- .check()

function p.count( frame )

   -- Count number of template parameters
   -- Postcondition:
   --     Return string with digits including "0"
   -- Uses:
   --     TemplatePar.count()
   return tostring( TemplatePar.count() )

end -- .count()

function p.countNotEmpty( frame )

   -- Count number of template parameters which are not empty
   -- Postcondition:
   --     Return string with digits including "0"
   -- Uses:
   --     TemplatePar.countNotEmpty()
   return tostring( TemplatePar.countNotEmpty() )

end -- .countNotEmpty()

function p.valid( frame )

   -- Check validity of one particular template parameter
   -- Precondition:
   --     frame  -- object; #invoke environment
   -- Postcondition:
   --     Return string with error message or ""
   -- Uses:
   --     furnish()
   return furnish( frame, "valid" )

end -- .valid()

function p.TemplatePar()

   -- Retrieve function access for modules
   -- Postcondition:
   --     Return table with functions
   return TemplatePar

end -- .TemplatePar()

return p