JasonWoof Got questions, comments, patches, etc.? Contact Jason Woofenden
remove unused method
[peach-html5-editor.git] / editor.coffee
index ec9f9f9..91f5c1c 100644 (file)
@@ -16,7 +16,7 @@
 
 # SETTINGS
 overlay_padding = 10
-breathing_room = 30 # minimum pixels above/below cursor
+breathing_room = 30 # minimum pixels above/below cursor (scrolling)
 
 timeout = (ms, cb) -> return setTimeout cb, ms
 next_frame = (cb) ->
@@ -73,12 +73,8 @@ js_attr_regex = new RegExp '^[oO][nN].'
 # html5 spec says that only these characters are collapsable
 multi_sp_regex = new RegExp '[\u0020\u0009\u000a\u000c\u000d][\u0020\u0009\u000a\u000c\u000d]'
 
-debug_dot_at = (doc, x, y) ->
-       return # disabled
-       el = doc.createElement 'div'
-       el.setAttribute 'style', "position: absolute; left: #{x}px; top: #{y}px; width: 1px; height: 3px; background-color: red"
-       doc.body.appendChild el
-       #console.log(new Error().stack)
+str_has_ws_run = (str) ->
+       return multi_sp_regex.test str
 
 # text nodes don't have getBoundingClientRect(), so use selection api to find
 # it.
@@ -521,163 +517,6 @@ tree_remove_empty_text_nodes = (tree) ->
                                n.parent.children.splice i, 1
                                break
 
-# pass a array of nodes (from parser library, ie it should have .el and .text)
-tree_dedup_space = (tree) ->
-       prev = cur = next = null
-       prev_i = cur_i = next_i = 0
-       prev_pos = pos = next_pos = null
-       prev_px = cur_px = next_px = null
-       first = true
-       removed_char = null
-
-       tree_remove_empty_text_nodes(tree)
-
-       iterate = (tree, cb) ->
-               for n in tree
-                       if n.type is 'text'
-                               i = 0
-                               while i < n.text.length # don't foreach, cb might remove chars
-                                       advance = cb n, i
-                                       if advance
-                                               i += 1
-                       if n.type is 'tag'
-                               block = is_display_block n.el
-                               if block
-                                       cb null
-                               if n.children.length > 0
-                                       iterate n.children, cb
-                               if block
-                                       cb null
-       # remove cur char
-       remove = (undo) ->
-               if undo
-                       cur.el.textContent = cur.text = (cur.text.substr 0, cur_i) + removed_char + (cur.text.substr cur_i)
-                       if next is cur # in same text node
-                               next_i += 1
-                       return -1
-               else
-                       removed_char = cur.text.charAt(cur_i)
-                       cur.el.textContent = cur.text = (cur.text.substr 0, cur_i) + (cur.text.substr cur_i + 1)
-                       if next is cur # in same text node
-                               if next_i is 0
-                                       throw "how is this possible?"
-                               next_i -= 1
-                       return 1
-       replace_with_space = (undo) ->
-               if undo
-                       cur.text = (cur.text.substr 0, cur_i) + removed_char + (cur.text.substr cur_i + 1)
-                       cur.el.textContent = cur.text
-               else
-                       removed_char = cur.text.charAt(cur_i)
-                       if removed_char isnt ' '
-                               cur.text = (cur.text.substr 0, cur_i) + ' ' + (cur.text.substr cur_i + 1)
-                               cur.el.textContent = cur.text
-               return 0
-       # return true if cur was removed from the dom (ie re-use same prev)
-       operate = ->
-               # cur definitately set
-               # prev and/or next might be null, indicating the start/end of a display:block
-               return false unless is_space_code cur.text.charCodeAt cur_i
-               fixers = [remove, replace_with_space]
-               # check for common case: single whitespace surrounded by non-whitespace chars
-               if prev? and next?
-                       unless (is_space_code prev.text.charCodeAt prev_i) or (is_space_code next.text.charCodeAt next_i)
-                               dbg = cur.text.charCodeAt cur_i
-                               if cur.text.charAt(cur_i) is ' ' # perens required
-                                       # single space can't collapse, doesn't need fixin'
-                                       return false
-                               else
-                                       # tab, newline, etc, can't collapse, but maybe should be replaced
-                                       fixers = [replace_with_space]
-               bounds = text_range_bounds cur.el, cur_i, cur_i + 1
-               # consistent cases:
-               # 1. zero rects returned by getClientRects() means collapsed space
-               if bounds is null
-                       return remove()
-               # 2. width greater than zero means visible space
-               if bounds.w > 0
-                       # has bounds, don't try removing
-                       fixers = [replace_with_space]
-               # now the weird edge cases...
-               #
-               # firefox and chromium both report zero width for characters at the end
-               # of a line where the text wraps (automatically, due to word-wrap) to
-               # the next line. These do not appear to be distinguishable from
-               # collapsed spaces via the range/bounds api, so...
-               #
-               # remove it from the dom, and if prev or next moves, put it back.
-               #
-               # this block (try changing it, put it back if something moves) is also
-               # used on collapsable whitespace characters besides space. In this case
-               # the character is replaced with a normal space character instead of
-               # removed
-               if prev? and not prev_px?
-                       prev_px = new_cursor_position n: prev, i: prev_i
-               if next? and not next_px?
-                       next_px = new_cursor_position n: next, i: next_i
-               #if prev is null and next is null
-               #       parent_px = cur.parent.el.getBoundingClientRect()
-               undo_arg = true # just for readabality
-               removed = 0
-               for fixer in fixers
-                       break if removed > 0
-                       removed += fixer()
-                       need_undo = false
-                       if prev?
-                               if prev_px?
-                                       new_prev_px = new_cursor_position n: prev, i: prev_i
-                                       if new_prev_px?
-                                               if new_prev_px.x isnt prev_px.x or new_prev_px.y isnt prev_px.y
-                                                       need_undo = true
-                                       else
-                                               need_undo = true
-                               else
-                                       console.log "this shouldn't happen, we remove spaces that don't locate"
-                       if next? and not need_undo
-                               if next_px?
-                                       new_next_px = new_cursor_position n: next, i: next_i
-                                       if new_next_px?
-                                               if new_next_px.x isnt next_px.x or new_next_px.y isnt next_px.y
-                                                       need_undo = true
-                                       else
-                                               need_undo = true
-                               #else
-                               #       console.log "removing space becase space after it is collapsed"
-                       if need_undo
-                               removed += fixer undo_arg
-               if removed > 0
-                       return true
-               else
-                       return false
-       # pass null at start/end of display:block
-       queue = (n, i) ->
-               next = n
-               next_i = i
-               next_px = null
-               advance = true
-               if cur?
-                       removed = operate()
-                       # don't advance (to the next character next time) if we removed a
-                       # character from the same text node as ``next``, because doing so
-                       # renumbers the indexes in that string
-                       if removed and cur is next
-                               advance = false
-               else
-                       removed = false
-               unless removed
-                       prev = cur
-                       prev_i = cur_i
-                       prev_px = cur_px
-               cur = next
-               cur_i = next_i
-               cur_px = next_px
-               return advance
-       queue null
-       iterate tree, queue
-       queue null
-
-       tree_remove_empty_text_nodes(tree)
-
 class PeachHTML5Editor
        # Options: (all optional)
        #   editor_id: "id" attribute for outer-most element created by/for editor
@@ -949,15 +788,22 @@ class PeachHTML5Editor
                                return false
                        when KEY_DELETE
                                return false unless @cursor?
-                               return false unless @cursor.i < @cursor.n.text.length
-                               @remove_character @cursor.n, @cursor.i
-                               @text_cleanup @cursor.n
-                               @changed()
-                               new_cursor = new_cursor_position n: @cursor.n, i: @cursor.i
+                               new_cursor = find_next_cursor_position @tree, n: @cursor.n, i: @cursor.i
+                               # try moving cursor right and then running backspace code
+                               # TODO replace this hack with a real implementation
                                if new_cursor?
-                                       @move_cursor new_cursor
-                               else
-                                       @kill_cursor()
+                                       # try to detect common case where cursor goes inside an block,
+                                       # but doesn't pass a character (and advance one more in that case)
+                                       if new_cursor.n isnt @cursor.n and new_cursor.i is 0
+                                               if new_cursor.n.type is 'text' and new_cursor.n.text.length > 0
+                                                       if new_cursor.n.parent?
+                                                               unless @is_display_block new_cursor.n.parent
+                                                                       # FIXME should test run sibling
+                                                                       new_cursor = new_cursor_position n: new_cursor.n, i: new_cursor.i + 1
+                               if new_cursor?
+                                       if new_cursor.n isnt @cursor.n or new_cursor.i isnt @cursor.i
+                                               @move_cursor new_cursor
+                                               @on_key_backspace e
                                return false
                        when KEY_ENTER
                                @on_key_enter e
@@ -1050,13 +896,13 @@ class PeachHTML5Editor
        # that are flowing/wrapping together. n can be the containing block, or any
        # element inside it.
        get_text_run: (n) ->
+               ret = []
                if @is_display_block n
                        block = n
                else
                        block = @find_block_parent n
-                       return unless block?
-               ret = []
-               traverse_tree n.children, (n) =>
+                       return ret unless block?
+               traverse_tree block.children, (n) =>
                        if n.type is 'text'
                                ret.push n
                        else if n.type is 'tag'
@@ -1068,135 +914,179 @@ class PeachHTML5Editor
                                                ret.push n
                        return false # not done traversing
                return ret
+       node_is_decendant: (young, old) ->
+               while young? and young != @tree_parent
+                       return true if young is old
+                       young = young.parent
+               return false
+       # helper for on_key_backspace
+       _merge_left: (state) ->
+               # the node prev to n was not prev to it a moment ago, merge with it if reasonable
+               pi = state.n.parent.children.indexOf(state.n)
+               if pi > 0
+                       prev = state.n.parent.children[pi - 1]
+                       if prev.type is 'text'
+                               state.i = prev.text.length
+                               prev.text = prev.el.textContent = prev.text + state.n.text
+                               @remove_node state.n
+                               state.n = prev
+                               state.changed = true
+                               state.moved_cursor = true
+               # else # TODO merge possible consecutive matching inline tags at @cursor
+               return state
+       # helper for on_key_backspace
+       # remove n from the dom, also remove its inline parents that are emptied by removing n
+       _backspace_node_helper: (n, run = @get_text_run(n), run_i = run.indexOf(n)) ->
+               block = @find_block_parent n
+               # delete text node
+               @remove_node n
+               # delete any inline parents
+               n = n.parent
+               while n? and n isnt block
+                       # bail if the previous node in this run is also inside the same parent
+                       if run_i > 0
+                               break if @node_is_decendant run[run_i - 1], n
+                       # bail if the next node in this run is also inside the same parent
+                       if run_i + 1 < run.length
+                               break if @node_is_decendant run[run_i + 1], n
+                       # move any sibling nodes to parent. These nodes are not in the text run
+                       while n.children.length > 0
+                               @move_node n.children[0], n.parent, n
+                       # remove (now completely empty) inline parent
+                       @remove_node n
+                       # proceed to outer parent
+                       n = n.parent
+               return
        on_key_backspace: (e) ->
-               return false unless @cursor?
-               if @is_lone_space @cursor.n # false if it's not in a tag
-                       if @cursor.i is 1
-                               # don't delete the space, because then it would collapse
-                               # instead leave a space after the cursor
-                               new_cursor = new_cursor_position n: @cursor.n, i: 0
-                               if new_cursor?
-                                       @move_cursor new_cursor
-                               else
-                                       @kill_cursor()
-                       else
-                               # cursor at the begining of an element that contains only a space
-                               parent = @cursor.n.parent
-                               new_cursor = find_prev_cursor_position @tree, @cursor
-                               if new_cursor?
-                                       if new_cursor.n is @cursor.n or new_cursor.n is parent
-                                               new_cursor = null
-                               tag = @cursor.n.parent
-                               if tag is @tree_parent
-                                       console.log "top-level text not supported" # FIXME
-                                       return false
-                               for n, i in tag.parent.children
-                                       if n is tag
-                                               tag.parent.el.removeChild tag.el
-                                               tag.parent.children.splice i, 1
-                                               break
-                               @changed()
-                               if new_cursor?
-                                       # re-check, in case it moved or is invalid now
-                                       new_cursor = new_cursor_position n: new_cursor.n, i: new_cursor.i
+               return unless @cursor?
+               new_cursor = null
+               run = null
+               changed = true
+               if @cursor.i is 0 # cursor is at start of text node
+                       run ?= @get_text_run @cursor.n
+                       run_i = run.indexOf(@cursor.n)
+                       if run_i is 0 # if at start of text run
+                               block = @find_block_parent @cursor.n
+                               prev_cursor = find_prev_cursor_position @tree, n: @cursor.n, i: 0
+                               if prev_cursor is null # if in first text run of document
+                                       # do nothing (there's nothing text-like to the left of the cursor)
+                                       return
+                               # else merge with prev/outer text run
+                               pcb = @find_block_parent prev_cursor.n
+                               while block.children.length > 0
+                                       @move_node block.children[0], pcb
+                               @remove_node block
+                               # merge possible consecutive text nodes at @cursor
+                               merge_state = n: @cursor.n
+                               @_merge_left merge_state
+                               @text_cleanup merge_state.n
+                               new_cursor = new_cursor_position n: merge_state.n, i: merge_state.i
+                       else # at start of text node, but not start of text run
+                               prev = run[run_i - 1]
+                               if prev.type is 'text' # if previous in text run is text
+                                       if prev.text.length is 1 # if emptying prev (in text run)
+                                               @_backspace_node_helper prev, run, run_i
+                                               merge_state = n: @cursor.n, i: @cursor.i
+                                               @_merge_left merge_state
+                                               @text_cleanup merge_state.n
+                                               new_cursor = new_cursor_position n: merge_state.n, i: merge_state.i
+                                       else # prev in run is text with muliple chars
+                                               # delete last character in prev
+                                               prev.text = prev.text.substr(0, prev.text.length - 1)
+                                               prev.el.textContent = prev.text
+                                               @text_cleanup @cursor.n
+                                               new_cursor = new_cursor_position n: @cursor.n, i: @cursor.i
+                               else if prev.name is 'br' or prev.name is 'hr'
+                                       @_backspace_node_helper prev, run, run_i
+                                       merge_state = n: @cursor.n, i: @cursor.i
+                                       @_merge_left merge_state
+                                       @text_cleanup merge_state.n
+                                       new_cursor = new_cursor_position n: merge_state.n, i: merge_state.i
+                               # FIXME implement this:
+                               # else # if prev (in run) is inline-block
+                                       # if that inline-block has text in it
+                                               # delete last char in prev inlineblock
+                                               # if that empties it
+                                                       # delete it
+                                                       # merge left
+                                               # else
+                                                       # move cursor inside
+                                       # else
+                                               # delete prev (inline) block
+                                               # merge left
+                                       # auto-delete this @cursor.parent(s) if this empties them
+               else # cursor is not at start of text node
+                       run ?= @get_text_run @cursor.n
+                       if @cursor.n.text.length is 1 # if emptying text node
+                               if run.length is 1 # if emptying text run (of text/br/hr/inline-block)
+                                       # remove inline-parents of @cursor.n
+                                       block = @find_block_parent @cursor.n
+                                       changed = false
+                                       n = @cursor.n.parent
+                                       # note: this doesn't use _backspace_node_helper because:
+                                       # 1. we don't want to delete the target node (we're replacing it's contents)
+                                       # 2. we want to track whether anything was removed
+                                       # 3. we know already know there's no other text from this run anywhere
+                                       while n and n isnt block
+                                               changed = true
+                                               while n.children.length > 0
+                                                       @move_node n.children[0], n.parent, n
+                                               @remove_node n
+                                               n = n.parent
+                                       # replace @cursor.n with a single (preserved) space
+                                       if @cursor.n.text != ' '
+                                               changed = true
+                                               @cursor.n.text = @cursor.n.el.textContent = ' '
+                                       if changed
+                                               @text_cleanup @cursor.n
+                                       # place the cursor to the left of that space
+                                       new_cursor = new_cursor_position n: @cursor.n, i: 0
+                               else # emptying a text node (but not a whole text run)
+                                       # figure out where cursor should land
+                                       block = @find_block_parent @cursor.n
+                                       new_cursor = find_prev_cursor_position @tree, n: @cursor.n, i: 0
+                                       ncb = @find_block_parent new_cursor.n
+                                       if ncb isnt block
+                                               new_cursor = find_next_cursor_position @tree, n: @cursor.n, i: 1
+                                       # delete text node and cleanup emptied parents
+                                       run_i = run.indexOf @cursor.n
+                                       @_backspace_node_helper @cursor.n, run, run_i
+                                       # see if new adjacent siblings should merge
+                                       # TODO make smarter
+                                       if run_i > 0 and run_i + 1 < run.length
+                                               if run[run_i - 1].type is 'text' and run[run_i + 1].type is 'text'
+                                                       merge_state = n: run[run_i + 1]
+                                                       @_merge_left merge_state
+                                                       if merge_state.moved_cursor
+                                                               new_cursor = merge_state
+                                       # update whitespace preservation
+                                       @text_cleanup(block)
+                                       # update cursor x/y in case things moved around
                                        if new_cursor?
-                                               @move_cursor new_cursor
-                                               return
-                               new_cursor = first_cursor_position @tree
-                               if new_cursor?
-                                       @move_cursor new_cursor
-                               else
-                                       @kill_cursor
-                               return
-               else if @cursor.i is 0 # start of text chunk
-                       # FIXME clean this up: use new code for text runs
-                       # FIXME handle backspacing a <br> even if it's near a inline tag boundary
-                       # determine if cursor is at start of text run (text formatted inline)
-                       block = @find_block_parent @cursor.n
-                       return unless block
-                       at_block_start = true
-                       prev_pos = find_prev_cursor_position @tree, @cursor
-                       unless prev_pos?
-                               # if the cursor can't go back, then there's probably nowhere we can merge into
-                               # TODO consider case of nested blocks. should backspace remove one?
-                               return
-                       prev_pos_block = @find_block_parent prev_pos.n
-                       if prev_pos_block is block
-                               # context: there is text before the cursor within the same block.
-                               # FIXME clean up this hack for looking for <br> (see above)
-                               cursor_text_pi = @cursor.n.parent.children.indexOf @cursor.n
-                               if cursor_text_pi > 0
-                                       prev_node = @cursor.n.parent.children[cursor_text_pi - 1]
-                                       if prev_node.type is 'tag' and prev_node.name is 'br'
-                                               @remove_node prev_node
-                                               @text_cleanup @cursor.n.parent
-                                               @changed()
-                                               new_cursor = new_cursor_position n: prev_pos.n, i: prev_pos.i
-                                               if new_cursor?
-                                                       @move_cursor new_cursor
+                                               if new_cursor.n.el.parentNode # still in dom after cleanup
+                                                       new_cursor = new_cursor_position n: new_cursor.n, i: new_cursor.i
                                                else
-                                                       @kill_cursor
-                                               return
-                               # note: find_prev_cursor_position just crossed a boundary, not a character
-                               # prev_pos is within the same block, try deleting there
-                               @move_cursor prev_pos
-                               # FIXME cleanup: don't call @move_cursor twice if the next line succeeds
-                               return @on_key_backspace()
-                       # context: backspace pressed at start of a display:block
-                       return if block is @tree_parent # top level text
-                       parent = block.parent
-                       parent_i = parent.children.indexOf block
-                       if parent_i is -1
-                               throw "BUG #98270918347"
-                               return
-                       if parent_i is 0
-                               # no previous sibling to merge into, so instead move contents into parent
-                               dest = parent
-                               before = block
-                       else
-                               # FIXME prev_sib should be the previous in-flow element
-                               # ie it should skip comments, hidden things, floating things, etc.
-                               prev_sib = parent.children[parent_i - 1]
-                               if @is_display_block prev_sib
-                                       dest = prev_sib
-                                       before = null # null means append
-                               else
-                                       dest = parent
-                                       before = block
-                       if dest is @tree_parent
-                               # don't remove outer-most blocks
-                               return
-                       while block.children.length > 0
-                               n = block.children[block.children.length - 1]
-                               @move_node n, dest, before
-                               before = n
-                       @remove_node block
-                       @text_cleanup dest
+                                                       new_cursor = null
+                       else # there's a char left of cursor that we can delete without emptying anything
+                               # delete character
+                               need_text_cleanup = true
+                               if @cursor.i > 1 and @cursor.i < @cursor.n.text.length
+                                       pre = @cursor.n.text.substr(@cursor.i - 2, 3)
+                                       post = pre.charAt(0) + pre.charAt(2)
+                                       if str_has_ws_run(pre) is str_has_ws_run(post)
+                                               need_text_cleanup = false
+                               @remove_character(@cursor.n, @cursor.i - 1)
+                               # call text_cleanup if whe created/removed a whitespace run
+                               if need_text_cleanup
+                                       @text_cleanup @cursor.n
+                               new_cursor = new_cursor_position n: @cursor.n, i: @cursor.i - 1
+               # mark document changed and move the cursor
+               if changed?
                        @changed()
-                       new_cursor = new_cursor_position n: prev_pos.n, i: prev_pos.i
-                       if new_cursor?
-                               @move_cursor new_cursor
-                       else
-                               @kill_cursor
-                       return
+               if new_cursor?
+                       @move_cursor new_cursor
                else
-                       # TODO handle case of removing last char
-                       # CONTINUE
-                       if @is_only_char_in_tag @cursor.n
-                               if @is_display_block @cursor.n.parent
-                                       @cursor.n.el.textContent = @cursor.n.text = ' '
-                               else
-                                       console.log "unimplemented: delete last char in inline" # FIXME
-                                       return
-                       else
-                               @remove_character @cursor.n, @cursor.i - 1
-                       @text_cleanup @cursor.n
-                       @changed()
-                       new_cursor = new_cursor_position n: @cursor.n, i: @cursor.i - 1
-                       if new_cursor?
-                               @move_cursor new_cursor
-                       else
-                               @kill_cursor()
+                       @kill_cursor()
                return
        on_page_up_key: (e) ->
                if @wrap2.scrollTop is 0
@@ -1294,7 +1184,7 @@ class PeachHTML5Editor
                @tree_parent.el = @idoc.body
                @clear_dom()
                instantiate_tree @tree, @tree_parent.el
-               tree_dedup_space @tree
+               @collapse_whitespace @tree
                @changed()
        changed: ->
                @in_el.onchange = null
@@ -1311,28 +1201,6 @@ class PeachHTML5Editor
                h = parseInt(@idoc.body.scrollHeight, 10)
                @iframe.style.height = "#{h}px"
                @wrap2.scrollTop = s
-       # does this node have whitespace that would be collapsed by white-space: normal?
-       # note: this checks direct text children, and does _not_ recurse into child tags
-       # tag is a node with type:"tag"
-       # FIXME use new textrun api
-       has_collapsable_space: (tag) ->
-               for n in tag.children
-                       if n.type is 'text'
-                               for i in [0...n.text.length]
-                                       code = n.text.charCodeAt i
-                                       if code isnt 32 and is_space_code code
-                                               # tab, return
-                                               return true
-                                       # check for double spaces that don't surround insert location
-                                       continue if i is 0
-                                       if n.text.substr(i - 1, 2) is '  '
-                                               return true
-                               if n.text.length > 0
-                                       if is_space_code n.text.charCodeAt 0
-                                               return true
-                                       if is_space_code n.text.charCodeAt n.text.length - 1
-                                               return true
-               return false
        # true if n is text node with only one caracter, and the only child of a tag
        is_only_char_in_tag: (n, i) ->
                return false unless n.type is 'text'
@@ -1407,10 +1275,172 @@ class PeachHTML5Editor
                else
                        if n.attrs.style?
                                delete n.attrs.style
+       # remove whitespace that would be trimmed
+       # replace whitespace that would collapse with a single space
+       # FIXME remove whitespace from after <br> (but not before)
+       collapse_whitespace: (tree = @tree) ->
+               prev = cur = next = null
+               prev_i = cur_i = next_i = 0
+               prev_pos = pos = next_pos = null
+               prev_px = cur_px = next_px = null
+               first = true
+               removed_char = null
+
+               tree_remove_empty_text_nodes(tree)
+
+               iterate = (tree, cb) ->
+                       for n in tree
+                               if n.type is 'text'
+                                       i = 0
+                                       while i < n.text.length # don't foreach, cb might remove chars
+                                               advance = cb n, i
+                                               if advance
+                                                       i += 1
+                               if n.type is 'tag'
+                                       block = is_display_block n.el
+                                       if block
+                                               cb null
+                                       if n.children.length > 0
+                                               iterate n.children, cb
+                                       if block
+                                               cb null
+               # remove cur char
+               remove = (undo) ->
+                       if undo
+                               cur.el.textContent = cur.text = (cur.text.substr 0, cur_i) + removed_char + (cur.text.substr cur_i)
+                               if next is cur # in same text node
+                                       next_i += 1
+                               return -1
+                       else
+                               removed_char = cur.text.charAt(cur_i)
+                               cur.el.textContent = cur.text = (cur.text.substr 0, cur_i) + (cur.text.substr cur_i + 1)
+                               if next is cur # in same text node
+                                       if next_i is 0
+                                               throw "how is this possible?"
+                                       next_i -= 1
+                               return 1
+               replace_with_space = (undo) ->
+                       if undo
+                               cur.text = (cur.text.substr 0, cur_i) + removed_char + (cur.text.substr cur_i + 1)
+                               cur.el.textContent = cur.text
+                       else
+                               removed_char = cur.text.charAt(cur_i)
+                               if removed_char isnt ' '
+                                       cur.text = (cur.text.substr 0, cur_i) + ' ' + (cur.text.substr cur_i + 1)
+                                       cur.el.textContent = cur.text
+                       return 0
+               # return true if cur was removed from the dom (ie re-use same prev)
+               operate = ->
+                       # cur definitately set
+                       # prev and/or next might be null, indicating the start/end of a display:block
+                       return false unless is_space_code cur.text.charCodeAt cur_i
+                       fixers = [remove, replace_with_space]
+                       # check for common case: single whitespace surrounded by non-whitespace chars
+                       if prev? and next?
+                               unless (is_space_code prev.text.charCodeAt prev_i) or (is_space_code next.text.charCodeAt next_i)
+                                       dbg = cur.text.charCodeAt cur_i
+                                       if cur.text.charAt(cur_i) is ' ' # perens required
+                                               # single space can't collapse, doesn't need fixin'
+                                               return false
+                                       else
+                                               # tab, newline, etc, can't collapse, but maybe should be replaced
+                                               fixers = [replace_with_space]
+                       bounds = text_range_bounds cur.el, cur_i, cur_i + 1
+                       # consistent cases:
+                       # 1. zero rects returned by getClientRects() means collapsed space
+                       if bounds is null
+                               return remove()
+                       # 2. width greater than zero means visible space
+                       if bounds.w > 0
+                               # has bounds, don't try removing
+                               fixers = [replace_with_space]
+                       # now the weird edge cases...
+                       #
+                       # firefox and chromium both report zero width for characters at the end
+                       # of a line where the text wraps (automatically, due to word-wrap) to
+                       # the next line. These do not appear to be distinguishable from
+                       # collapsed spaces via the range/bounds api, so...
+                       #
+                       # remove it from the dom, and if prev or next moves, put it back.
+                       #
+                       # this block (try changing it, put it back if something moves) is also
+                       # used on collapsable whitespace characters besides space. In this case
+                       # the character is replaced with a normal space character instead of
+                       # removed
+                       if prev? and not prev_px?
+                               prev_px = new_cursor_position n: prev, i: prev_i
+                       if next? and not next_px?
+                               next_px = new_cursor_position n: next, i: next_i
+                       #if prev is null and next is null
+                       #       parent_px = cur.parent.el.getBoundingClientRect()
+                       undo_arg = true # just for readabality
+                       removed = 0
+                       for fixer in fixers
+                               break if removed > 0
+                               removed += fixer()
+                               need_undo = false
+                               if prev?
+                                       if prev_px?
+                                               new_prev_px = new_cursor_position n: prev, i: prev_i
+                                               if new_prev_px?
+                                                       if new_prev_px.x isnt prev_px.x or new_prev_px.y isnt prev_px.y
+                                                               need_undo = true
+                                               else
+                                                       need_undo = true
+                                       else
+                                               console.log "this shouldn't happen, we remove spaces that don't locate"
+                               if next? and not need_undo
+                                       if next_px?
+                                               new_next_px = new_cursor_position n: next, i: next_i
+                                               if new_next_px?
+                                                       if new_next_px.x isnt next_px.x or new_next_px.y isnt next_px.y
+                                                               need_undo = true
+                                               else
+                                                       need_undo = true
+                                       #else
+                                       #       console.log "removing space becase space after it is collapsed"
+                               if need_undo
+                                       removed += fixer undo_arg
+                       if removed > 0
+                               return true
+                       else
+                               return false
+               # pass null at start/end of display:block
+               queue = (n, i) ->
+                       next = n
+                       next_i = i
+                       next_px = null
+                       advance = true
+                       if cur?
+                               removed = operate()
+                               # don't advance (to the next character next time) if we removed a
+                               # character from the same text node as ``next``, because doing so
+                               # renumbers the indexes in that string
+                               if removed and cur is next
+                                       advance = false
+                       else
+                               removed = false
+                       unless removed
+                               prev = cur
+                               prev_i = cur_i
+                               prev_px = cur_px
+                       cur = next
+                       cur_i = next_i
+                       cur_px = next_px
+                       return advance
+               queue null
+               iterate tree, queue
+               queue null
+
+               tree_remove_empty_text_nodes(tree)
+               return
        # call this after you insert or remove inline nodes. It will:
        #    merge consecutive text nodes
        #    remove empty text nodes
        #    adjust white-space property
+       # note: this assumes that all whitespace in text nodes should be displayed
+       # (ie not collapse or be trimmed) and will change the white-space property
+       # as needed to achieve this.
        text_cleanup: (n) ->
                if @is_display_block n
                        block = n