--- Cloze uses [LDoc](https://github.com/stevedonovan/ldoc) for the -- source code documentation. The supported tags are described on in -- the [wiki](https://github.com/stevedonovan/LDoc/wiki). -- --

Naming conventions

-- -- * _Variable_ names for _nodes_ are suffixed with `_node`, for example -- `head_node`. -- * _Variable_ names for _lengths_ (dimensions) are suffixed with -- `_length`, for example `width_length`. -- -- @module cloze -- __cloze.lua}__ -- __Initialisation of the function tables__ -- It is good form to provide some background informations about this Lua -- module. if not modules then modules = { } end modules ['cloze'] = { version = '1.5', comment = 'cloze', author = 'Josef Friedrich, R.-M. Huber', copyright = 'Josef Friedrich, R.-M. Huber', license = 'The LaTeX Project Public License Version 1.3c 2008-05-04' } --- `nodex` is a abbreviation for __node eXtended__. local nodex = {} --- All values and functions, which are related to the option management, -- are stored in a table called `registry`. local registry = {} --- I didn't know what value I should take as `user_id`. Therefore I -- took my birthday and transformed it to a large number. registry.user_id = 3121978 registry.storage = {} registry.defaults = { ['align'] = 'l', ['boxheight'] = false, ['boxwidth'] = '\\linewidth', ['distance'] = '1.5pt', ['hide'] = false, ['linecolor'] = '0 0 0 rg 0 0 0 RG', -- black ['linecolor_name'] = 'black', ['margin'] = '3pt', ['resetcolor'] = '0 0 0 rg 0 0 0 RG', -- black ['resetcolor_name'] = 'black', ['show_text'] = true, ['show'] = true, ['spacing'] = '1.6', ['textcolor'] = '0 0 1 rg 0 0 1 RG', -- blue ['textcolor_name'] = 'blue', -- blue ['thickness'] = '0.4pt', ['width'] = '2cm', } registry.global_options = {} registry.local_options = {} -- All those functions are stored in the table `cloze` that are -- registered as callbacks to the pre and post linebreak filters. local cloze = {} -- In the status table are stored state information, which are necessary -- for the recursive cloze generation. cloze.status = {} -- The `base` table contains some basic functions. `base` is the only -- table of this Lua module that will be exported. local base = {} base.is_registered = {} --- Node precessing (nodex) -- @section nodex -- All functions in this section are stored in a table called `nodex`. -- `nodex` is a abbreviation for __node eXtended__. The `nodex` table -- bundles all functions, which extend the built-in `node` library. -- __Color handling (color)__ -- __create_colorstack__ -- Create a whatsit node of the subtype `pdf_colorstack`. `data` is a PDF -- colorstack string like `0 0 0 rg 0 0 0 RG`. function nodex.create_colorstack(data) if not data then data = '0 0 0 rg 0 0 0 RG' -- black end local whatsit = node.new('whatsit', 'pdf_colorstack') whatsit.stack = 0 whatsit.data = data return whatsit end --- -- `nodex.create_color()` is a wrapper for the function -- `nodex.create_colorstack()`. It queries the current values of the -- options `linecolor` and `textcolor`. The argument `option` accepts the -- strings `line`, `text` and `reset`. function nodex.create_color(option) local data if option == 'line' then data = registry.get_value('linecolor') elseif option == 'text' then data = registry.get_value('textcolor') elseif option == 'reset' then data = nil else data = nil end return nodex.create_colorstack(data) end -- __Line handling (line)__ --- Create a rule node, which is used as a line for the cloze texts. The -- `depth` and the `height` of the rule are calculated form the options -- `thickness` and `distance`. The argument `width` must have the length -- unit __scaled points__. function nodex.create_line(width) local rule = node.new(node.id('rule')) local thickness = tex.sp(registry.get_value('thickness')) local distance = tex.sp(registry.get_value('distance')) rule.depth = distance + thickness rule.height = - distance rule.width = width return rule end --- Insert a `list` of nodes after or before the `current`. The `head` -- argument is optional. In some edge cases it is unfortately necessary. -- if `head` is omitted the `current` node is used. The argument -- `position` can take the values `'after'` or `'before'`. function nodex.insert_list(position, current, list, head_node) if not head_node then head_node = current end for i, insert in ipairs(list) do if position == 'after' then head_node, current = node.insert_after(head_node, current, insert) elseif position == 'before' then head_node, current = node.insert_before(head_node, current, insert) end end return current end --- Enclose a rule node (cloze line) with two PDF colorstack whatsits. -- The first colorstack node dyes the line, the seccond resets the -- color. -- -- __Node list__ -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
`n.color_line``whatsit``pdf_colorstack`Line color
`n.line``rule``width`
`n.color_reset``whatsit``pdf_colorstack`Reset color
function nodex.insert_line(current, width) return nodex.insert_list( 'after', current, { nodex.create_color('line'), nodex.create_line(width), nodex.create_color('reset') } ) end --- This function enclozes a rule node with color nodes as it the function -- `nodex.insert_line` does. In contrast to `nodex.insert_line` the three -- nodes are appended to \TeX’s ‘current list’. They are not inserted in -- a node list, which is accessed by a Lua callback. -- -- __Node list__ -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
-`whatsit``pdf_colorstack`Line color
-`rule``width`
-`whatsit``pdf_colorstack`Reset color
function nodex.write_line() node.write(nodex.create_color('line')) node.write(nodex.create_line(tex.sp(registry.get_value('width')))) node.write(nodex.create_color('reset')) end -- __Handling of extendable lines (linefil)__ --- This function creates a line which stretchs indefinitely in the -- horizontal direction. function nodex.create_linefil() local glue = node.new('glue') glue.subtype = 100 glue.stretch = 65536 glue.stretch_order = 3 local rule = nodex.create_line(0) rule.dir = 'TLT' glue.leader = rule return glue end --- The function `nodex.write_linefil` surrounds a indefinitely strechable -- line with color whatsits and puts it to \TeX’s ‘current (node) list’. function nodex.write_linefil() node.write(nodex.create_color('line')) node.write(nodex.create_linefil()) node.write(nodex.create_color('reset')) end -- __Kern handling (kern)__ --- This function creates a kern node with a given width. The argument -- `width` had to be specified in scaled points. local function create_kern_node(width) local kern_node = node.new(node.id('kern')) kern_node.kern = width return kern_node end --- Add at the beginning of each `hlist` node list a strut (a invisible -- character). -- -- Now we can add line, color etc. nodes after the first node of a hlist -- not before - after is much more easier. -- -- @tparam node hlist_node -- -- @treturn node hlist_node -- @treturn node strut_node -- @treturn node head_node local function insert_strut_into_hlist(hlist_node) local head_node = hlist_node.head local kern_node = create_kern_node(0) local strut_node = node.insert_before(hlist_node.head, head_node, kern_node) hlist_node.head = head_node.prev return hlist_node, strut_node, head_node end --- Write kern nodes to the current node list. This kern nodes can be used -- to build a margin. function nodex.write_margin() local kern = create_kern_node(tex.sp(registry.get_value('margin'))) node.write(kern) end --- Search for a `hlist` (subtype `line`). -- -- Insert a strut node into the list if a hlist is found. -- -- @tparam node head_node The head of a node list. -- -- @treturn node|false Return false, if no `hlist` can -- be found. local function search_hlist(head_node) while head_node do if head_node.id == node.id('hlist') and head_node.subtype == 1 then return insert_strut_into_hlist(head_node) end head_node = head_node.next end return false end --- Option handling. -- -- The table `registry` bundels functions that deal with option handling. -- --

Marker processing (marker)

-- -- A marker is a whatsit node of the subtype `user_defined`. A marker has -- two purposes: -- -- * Mark the begin and the end of a gap. -- * Store a index number, that points to a Lua table, which holds -- some additional data like the local options. -- @section registry --- We create a user defined whatsit node that can store a number (type -- = 100). -- -- In order to distinguish this node from other user defined whatsit -- nodes we set the `user_id` to a large number. We call this whatsit -- node a marker. The argument `index` is a number, which is associated -- to values in the `registry.storage` table. function registry.create_marker(index) local marker = node.new('whatsit','user_defined') marker.type = 100 -- number marker.user_id = registry.user_id marker.value = index return marker end --- Write a marker node to \TeX's current node list. -- -- The argument `mode` accepts the string values `basic`, `fix` and -- `par`. The argument `position`. The argument `position` is either set -- to `start` or to `stop`. function registry.write_marker(mode, position) local index = registry.set_storage(mode, position) local marker = registry.create_marker(index) node.write(marker) end --- This functions checks if the given node `item` is a marker. function registry.is_marker(item) if item.id == node.id('whatsit') and item.subtype == node.subtype('user_defined') and item.user_id == registry.user_id then return true else return false end end --- This functions tests, whether the given node `item` is a marker. -- -- The argument `item` is a node. The argument `mode` accepts the string -- values `basic`, `fix` and `par`. The argument `position` is either -- set to `start` or to `stop`. function registry.check_marker(item, mode, position) local data = registry.get_marker_data(item) if data and data.mode == mode and data.position == position then return true else return false end end --- `registry.get_marker` returns the given marker. -- -- The argument `item` is a node. The argument `mode` accepts the string -- values `basic`, `fix` and `par`. The argument `position` is either -- set to `start` or to `stop`. function registry.get_marker(item, mode, position) local out if registry.check_marker(item, mode, position) then out = item else out = false end if out and position == 'start' then registry.get_marker_values(item) end return out end --- `registry.get_marker_data` tests whether the node `item` is a -- marker. -- -- The argument `item` is a node of unspecified type. function registry.get_marker_data(item) if item.id == node.id('whatsit') and item.subtype == node.subtype('user_defined') and item.user_id == registry.user_id then return registry.get_storage(item.value) else return false end end --- First this function saves the associatied values of a marker to the -- local options table. Second it returns this values. The argument -- `marker` is a whatsit node. function registry.get_marker_values(marker) local data = registry.get_marker_data(marker) registry.local_options = data.values return data.values end --- This function removes a given whatsit marker. -- -- It only deletes a node, if a marker is given. function registry.remove_marker(marker) if registry.is_marker(marker) then node.remove(marker, marker) end end -- __Storage functions (storage)__ --- `registry.index` is a counter. The functions `registry.get_index()` -- increases the counter by one and then returns it. function registry.get_index() if not registry.index then registry.index = 0 end registry.index = registry.index + 1 return registry.index end --- `registry.set_storage()` stores the local options in the Lua table -- `registry.storage`. -- -- It returns a numeric index number. This index number is the key, -- where the local options in the Lua table are stored. The argument -- `mode` accepts the string values `basic`, `fix` and `par`. function registry.set_storage(mode, position) local index = registry.get_index() local data = { ['mode'] = mode, ['position'] = position } data.values = registry.local_options registry.storage[index] = data return index end --- The function `registry.get_storage()` retrieves values which belong -- to a whatsit marker. -- -- The argument `index` is a numeric value. function registry.get_storage(index) return registry.storage[index] end -- __Option processing (option)__ --- This function stores a value `value` and his associated key `key` -- either to the global (`registry.global_options`) or to the local -- (`registry.local_options`) option table. -- -- The global boolean variable `registry.local_options` controls in -- which table the values are stored. function registry.set_option(key, value) if value == '' or value == '\\color@ ' then return false end if registry.is_global == true then registry.global_options[key] = value else registry.local_options[key] = value end end --- `registry.set_is_global()` sets the variable `registry.is_global` to -- the value `value`. It is intended, that the variable takes boolean -- values. function registry.set_is_global(value) registry.is_global = value end --- This function unsets the local options. function registry.unset_local_options() registry.local_options = {} end --- `registry.unset_global_options` empties the global options storage. function registry.unset_global_options() registry.global_options = {} end --- Retrieve a value from a given key. First search for the value in the -- local options, then in the global options. If both option storages are -- empty, the default value will be returned. function registry.get_value(key) if registry.has_value(registry.local_options[key]) then return registry.local_options[key] end if registry.has_value(registry.global_options[key]) then return registry.global_options[key] end return registry.defaults[key] end --- The function `registry.get_value_show()` returns the boolean value -- `true` if the option `show` is true. In contrast to the function -- `registry.get_value()` it converts the string value `true' to a -- boolean value. function registry.get_value_show() if registry.get_value('show') == true or registry.get_value('show') == 'true' then return true else return false end end --- This function tests whether the value `value` is not empty and has a -- value. function registry.has_value(value) if value == nil or value == '' or value == '\\color@ ' then return false else return true end end --- `registry.get_defaults(option)` returns a the default value of the -- given option. function registry.get_defaults(option) return registry.defaults[option] end --- Assembly to cloze texts. -- @section cloze_functions --- The function `cloze.basic_make()` makes one gap. The argument `start` -- is the node, where the gap begins. The argument `stop` is the node, -- where the gap ends. function cloze.basic_make(start_node, end_node) local node_head = start_node if not start_node or not end_node then return end local line_width = node.dimensions( cloze.status.hlist.glue_set, cloze.status.hlist.glue_sign, cloze.status.hlist.glue_order, start_node, end_node ) local line_node = nodex.insert_line(start_node, line_width) local color_text_node = nodex.insert_list('after', line_node, {nodex.create_color('text')}) if registry.get_value_show() then nodex.insert_list('after', color_text_node, {create_kern_node(-line_width)}) nodex.insert_list('before', end_node, {nodex.create_color('reset')}, node_head) else line_node.next = end_node.next end_node.prev = line_node -- not line_node.prev -> line color leaks out end -- In some edge cases the lua callbacks get fired up twice. After the -- cloze has been created, the start and stop whatsit markers can be -- deleted. registry.remove_marker(start_node) registry.remove_marker(end_node) end --- Search for a stop marker. -- -- @tparam node head_node The head of a node list. -- -- @treturn node The end node. function cloze.basic_search_stop(head_node) local end_node while head_node do cloze.status.continue = true end_node = head_node if registry.check_marker(end_node, 'basic', 'stop') then cloze.status.continue = false break end head_node = head_node.next end return end_node end --- Search for a start marker or begin a new cloze if the value -- `cloze.status.continue` is true. -- -- We have to find a hlist node and use its on the field `head` -- attached node list to search for a start marker. -- -- @tparam node head_node The head of a node list. function cloze.basic_search_start(head_node) local start_node, end_node, hlist_node if cloze.status.continue then hlist_node = search_hlist(head_node) if hlist_node then cloze.status.hlist = hlist_node start_node = hlist_node.head end elseif registry.check_marker(head_node, 'basic', 'start') then start_node = head_node end if start_node then end_node = cloze.basic_search_stop(start_node) cloze.basic_make(start_node, end_node) end end --- Parse the node tree recursivley. -- -- Start and end markers could be nested deeply in the node tree. -- -- @tparam node head_node The head of a node list. function cloze.basic_recursion(head_node) while head_node do if head_node.head then cloze.status.hlist = head_node cloze.basic_recursion(head_node.head) else cloze.basic_search_start(head_node) end head_node = head_node.next end end --- The corresponding LaTeX command to this lua function is `\cloze`. -- -- @tparam node head_node The head of a node list. -- -- @treturn node The head of the node list. function cloze.basic(head_node) cloze.status.continue = false cloze.basic_recursion(head_node) return head_node end --- Calculate the length of the whitespace before (`l.kern_start`) and -- after (`l.kern_stop`) the text. function cloze.fix_length(start, stop) local l = {} l.width = tex.sp(registry.get_value('width')) l.text_width = node.dimensions(start, stop) l.align = registry.get_value('align') if l.align == 'right' then l.kern_start = - l.text_width l.kern_stop = 0 elseif l.align == 'center' then l.half = (l.width - l.text_width) / 2 l.kern_start = - l.half - l.text_width l.kern_stop = l.half else l.kern_start = - l.width l.kern_stop = l.width - l.text_width end return l.width, l.kern_start, l.kern_stop end --- The function `cloze.fix_make` generates a gap of fixed width. -- -- __Node lists__ -- -- __Show text:__ -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
`n.start``whatsit``user_definded``index`
`n.line``rule``l.width`
`n.kern_start``kern`& Depends on `align`
`n.color_text``whatsit``pdf_colorstack`Text color
`glyphs`& Text to show
`n.color_reset``whatsit``pdf_colorstack`Reset color
`n.kern_stop``kern`& Depends on `align`
`n.stop``whatsit``user_definded``index`
-- -- __Hide text:__ -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
`n.start``whatsit``user_definded``index`
`n.line``rule``l.width`
`n.stop``whatsit``user_definded``index`
-- -- Make fixed size cloze. -- -- @param start The node, where the gap begins -- @param stop The node, where the gap ends function cloze.fix_make(start, stop) local l = {} -- length local n = {} -- node l.width, l.kern_start, l.kern_stop = cloze.fix_length(start, stop) n.line = nodex.insert_line(start, l.width) if registry.get_value_show() then nodex.insert_list( 'after', n.line, { create_kern_node(l.kern_start), nodex.create_color('text') } ) nodex.insert_list( 'before', stop, { nodex.create_color('reset'), create_kern_node(l.kern_stop) }, start ) else n.line.next = stop.next end registry.remove_marker(start) registry.remove_marker(stop) end --- Function to recurse the node list and search after marker. -- -- @tparam node head_node The head of a node list. function cloze.fix_recursion(head_node) local n = {} -- node n.start, n.stop = false while head_node do if head_node.head then cloze.fix_recursion(head_node.head) else if not n.start then n.start = registry.get_marker(head_node, 'fix', 'start') end if not n.stop then n.stop = registry.get_marker(head_node, 'fix', 'stop') end if n.start and n.stop then cloze.fix_make(n.start, n.stop) n.start, n.stop = false end end head_node = head_node.next end end --- The corresponding LaTeX command to this Lua function is `\clozefix`. -- -- @tparam node head_node The head of a node list. function cloze.fix(head_node) cloze.fix_recursion(head_node) return head_node end --- The corresponding LaTeX environment to this lua function is -- `clozepar`. -- -- __Node lists__ -- -- __Show text:__ -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
`n.strut``kern`width = 0
`n.line``rule``l.width` (Width from hlist)
`n.kern``kern``-l.width`
`n.color_text``whatsit``pdf_colorstack`Text color
`glyphs`Text to show
`n.tail``glyph`Last glyph in hlist
`n.color_reset``whatsit``pdf_colorstack`Reset color
-- -- __Hide text:__ -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
`n.strut``kern`width = 0
`n.line``rule``l.width` (Width from hlist)
-- -- @tparam node head_node The head of a node list. function cloze.par(head_node) local l = {} -- length local n = {} -- node for hlist in node.traverse_id(node.id('hlist'), head_node) do for whatsit in node.traverse_id(node.id('whatsit'), hlist.head) do registry.get_marker(whatsit, 'par', 'start') end l.width = hlist.width hlist, n.strut, n.head = insert_strut_into_hlist(hlist) n.line = nodex.insert_line(n.strut, l.width) if registry.get_value_show() then nodex.insert_list( 'after', n.line, { create_kern_node(-l.width), nodex.create_color('text') } ) nodex.insert_list( 'after', node.tail(head_node), {nodex.create_color('reset')} ) else n.line.next = nil end end return head_node end --- Basic module functions. -- The `base` table contains functions which are published to the -- `cloze.sty` file. -- @section base --- This function registers the functions `cloze.par`, `cloze.basic` and -- `cloze.fix` the Lua callbacks. -- -- `cloze.par` and `cloze.basic` are registered to the callback -- `post_linebreak_filter` and `cloze.fix` to the callback -- `pre_linebreak_filter`. The argument `mode` accepts the string values -- `basic`, `fix` and `par`. A special treatment is needed for clozes in -- display math mode. The `post_linebreak_filter` is not called on -- display math formulas. I’m not sure if the `pre_output_filter` is the -- right choice to capture the display math formulas. function base.register(mode) local basic if mode == 'par' then luatexbase.add_to_callback( 'post_linebreak_filter', cloze.par, mode ) return true end if not base.is_registered[mode] then if mode == 'basic' then luatexbase.add_to_callback( 'post_linebreak_filter', cloze.basic, mode ) luatexbase.add_to_callback( 'pre_output_filter', cloze.basic, mode ) elseif mode == 'fix' then luatexbase.add_to_callback( 'pre_linebreak_filter', cloze.fix, mode ) else return false end base.is_registered[mode] = true end end --- `base.unregister(mode)` deletes the registered functions from the -- Lua callbacks. -- -- @tparam string mode The argument `mode` accepts the string values -- `basic`, `fix` and `par`. function base.unregister(mode) if mode == 'basic' then luatexbase.remove_from_callback('post_linebreak_filter', mode) luatexbase.remove_from_callback('pre_output_filter', mode) elseif mode == 'fix' then luatexbase.remove_from_callback('pre_linebreak_filter', mode) else luatexbase.remove_from_callback('post_linebreak_filter', mode) end end -- Publish some functions to the `cloze.sty` file. base.linefil = nodex.write_linefil base.line = nodex.write_line base.margin = nodex.write_margin base.set_option = registry.set_option base.set_is_global = registry.set_is_global base.unset_local_options = registry.unset_local_options base.reset = registry.unset_global_options base.get_defaults = registry.get_defaults base.get_value = registry.get_value base.marker = registry.write_marker return base