Added a proof-of-concept implementation of \drawlist which draws linked lists

ch-tikz.tex

@@ -828,3 +828,241 @@
   \drawarray@NextArg
 }
 \makeatother
+
+%%%% draw list %%%%
+
+\makeatletter
+
+%% TODO: Implement directions and overflow handling
+
+\newcommand{\drawlist}[3][]{%
+  %% Draw an linked list inside a tikzpicture, highly customizable.
+  %%
+  %% Parameters:
+  %%
+  %%     #1 (optional): Options
+  %%     #2: List name
+  %%     #3: Index 0 content
+  %%     #N: index (N-3) content
+  %%
+  %% Options:
+  %%
+  %%     x = <x position>:
+  %%         sets the x position of the first element.
+  %%
+  %%     y = <y position>:
+  %%         sets the y position of the first element.
+  %%
+  %%     position = <coordinate or position>: This option
+  %%         overrides the x and y settings. Allows the user
+  %%         to specify a specific position which could be a
+  %%         named coordinate. For example:
+  %%
+  %%         \drawlist[anchor=north, position=node.south]{my list}{0}{1}{2}
+  %%
+  %%         will place an list directly underneath the named
+  %%         position 'node'.
+  %%
+  %%     anchor = <tikz anchor>:
+  %%         sets which anchor should be used when placing
+  %%         the first element node.
+  %%
+  %%     element = {<node styling>}:
+  %%         Passes the styling options to each element
+  %%         node.
+  %%
+  %%     element size = <size>:
+  %%         Set the minimum size of each element.
+  %%
+  %%     fill = <color>:
+  %%         Set a fill color for *all* the elements.
+  %%
+  %%     show index:
+  %%         Option that inserts a label for each index in
+  %%         the list as well, the position of the labels
+  %%         are set to 'south' by default. This is disabled
+  %%         by default.
+  %%
+  %%     index start = <start index>:
+  %%         Set what index the list should start at (0 by default).
+  %%
+  %%     index position = <left|right|up|down|west|east|north|south>:
+  %%         Specify which side of the nodes the index label
+  %%         should be placed. By default set to 'south'
+  %%
+  %%     index style = {<node styling>}:
+  %%         Passes the styling options to each index node.
+  %%
+  %% Example:
+  %%
+  %% \begin{tikzpicture}
+  %%   \drawlist[element size=1cm]{my list}{'a'}{'b'}{'c'}
+  %%   \drawlist[x=4cm, y=0cm]{other list}{1}{2}{34}
+  %% \end{tikzpicture}
+  %%
+  \pgfkeys{/drawlist, default, #1}%
+  \edef\list@Name{#2}%
+  \edef\list@Nodes{}%
+  \pgfmathtruncatemacro{\list@Index}{\list@StartIndex}%
+  %% Fix the coordinate either based on position or specific x and y coords
+  \ifx\list@Position\undefined%
+      \coordinate (list origin) at ($(\list@X, \list@Y) + (\list@xshift, \list@yshift)$);%
+  \else%
+      \coordinate (list origin) at ($(\list@Position) + (\list@xshift, \list@yshift)$);%
+  \fi%
+  % Once the initial position is set, undef it so that it is
+  % not defined for the next \drawlist
+  \undef\list@Position
+  \drawlist@Element[list origin]{#3}%
+
+  \pgfmathtruncatemacro{\list@Index}{\list@Index + 1}%
+  %% Goto next argument
+  \drawlist@NextArg%
+}
+
+\newcommand{\drawlistset}[1]{%
+  %% Allow the user to set specific keys and generate styles
+  %% etc. for the \drawlist command.
+  %%
+  %% Parameters:
+  %%
+  %%     #1: pgfkey statements, all occuring in the
+  %%         /drawlist family by default.
+  %%
+  %% Example:
+  %%
+  %% \drawlistset{my index/.style={show index, index style={font=\tiny\ttfamily}}}
+  %% \begin{tikzpicture}
+  %%   \drawlist[my index]{my list}{1}{2}{3}
+  %% \end{tikzpicture}
+  %%
+  \pgfkeys{/drawlist, #1}%
+}
+
+%% Options and settings for \drawlist
+\pgfkeys{
+  %% Create a family for \drawlist
+  /drawlist/.is family,
+  %% set /drawlist as the current family
+  /drawlist,
+  %% Assign the default values for each key
+  default/.style = {
+    x = 0,
+    y = 0,
+    offset=0.5cm,
+    xshift = 0,
+    yshift = 0,
+    anchor = center,
+    index style={},
+    index start=0,
+    index position=south,
+    element = {},
+    element size = 1.5em,
+    container = {},
+    fill=none,
+  },
+  %% x position of list
+  x/.estore in = \list@X,
+  %% y position of list
+  y/.estore in = \list@Y,
+  %% the offset between each node
+  offset/.estore in = \list@Offset,
+  position/.estore in = \list@Position,
+  %% shift operations
+  xshift/.estore in = \list@xshift,
+  yshift/.estore in = \list@yshift,
+  %% Which anchor of the first element should be used
+  anchor/.estore in = \list@Anchor,
+  %% Custom element settings
+  element/.code = {\tikzset{list element/.style={#1}}},
+  %% element size determines the size of the element
+  element size/.estore in = \list@ElementSize,
+  %% Custom styling for the container node
+  container/.code = {\tikzset{list container/.style={#1}}},
+  %% Show the index for each element
+  show index/.code = {\def\list@ShowIndex{1}},
+  index start/.estore in = \list@StartIndex,%
+  %% Position of the styling: takes the same options as 'direction'
+  index position/.style = {directions/#1/.get = \list@IndexPosition,%
+                           opposites/#1/.get = \list@IndexAnchor},
+  %% Customize index style
+  index style/.code = {\tikzset{list index/.style={#1}}},
+  %% Customized styling
+  fill/.estore in = \list@Fill,%
+  %% define each option for direction
+  /drawlist,
+  directions/.cd,
+  east/.initial  = east,
+  west/.initial  = west,
+  north/.initial = north,
+  south/.initial = south,
+  right/.initial = east,
+  left/.initial  = west,
+  up/.initial    = north,
+  down/.initial  = south,
+  %% define the different opposite directions
+  /drawlist,
+  opposites/.cd,
+  east/.initial  = west,
+  west/.initial  = east,
+  north/.initial = south,
+  south/.initial = north,
+  right/.initial = west,
+  left/.initial  = east,
+  up/.initial    = south,
+  down/.initial  = north
+}
+
+\newcommand{\drawlist@Element}[2][$(\ExpandWithSpaceBetween{\list@Name}{\list@PrevIndex}.east) + (\list@Offset, 0)$]{%
+  %% Save the nodes in a list so that we can pass to fit later
+  \xdef\list@Nodes{\list@Nodes(\ExpandWithSpaceBetween{\list@Name}{\list@Index})}%
+  \edef\list@CurrentValue{\ExpandWithSpaceBetween{\ExpandWithSpaceBetween{\list@Name}{value}}{\list@Index}}
+  \edef\list@CurrentNext{\ExpandWithSpaceBetween{\ExpandWithSpaceBetween{\list@Name}{next}}{\list@Index}}
+  \pgfmathtruncatemacro{\list@PrevIndex}{\list@Index - 1}%
+  \node[minimum width=\list@ElementSize,%
+        minimum height=\list@ElementSize,%
+        fill=\list@Fill,%
+        rectangle, draw=black, anchor=west,%
+        list element]%
+  (\list@CurrentValue)%
+  at (#1) {#2};%
+  \node[minimum width=\list@ElementSize,%
+        minimum height=\list@ElementSize,%
+        xshift=-\pgflinewidth,%
+        fill=\list@Fill,%
+        rectangle, draw=black, anchor=west,%
+        list element]%
+  (\list@CurrentNext)%
+  at (\list@CurrentValue.east) {};%  
+  \node[inner sep=0, outer sep=0, fit=(\list@CurrentValue)(\list@CurrentNext)]%
+  (\ExpandWithSpaceBetween{\list@Name}{\list@Index}) {};%
+  \ifx\list@ShowIndex\undefined%
+  % Do nothing
+  \else%
+      \node[list index, anchor=\list@IndexAnchor]%
+      (\ExpandWithSpaceBetween{\list@Name label}{\list@Index})%
+      at (\ExpandWithSpaceBetween{\list@Name}{\list@Index}.\list@IndexPosition) {\list@Index};%
+  \fi%
+}
+
+%% Check if next character after the macro is a opening
+%% curly brace, if it is expand \drawlist@GobbleArg to
+%% process the content of those braces, otherwise: generate
+%% the container node.
+\newcommand{\drawlist@NextArg}{%
+  \@ifnextchar\bgroup{%
+    \drawlist@GobbleArg%
+  }{%
+    \node[inner sep=0, outer sep=0,%
+          list container, fit=\list@Nodes] (\list@Name) {};%
+  }%
+}%
+
+\newcommand{\drawlist@GobbleArg}[1]{%
+  \drawlist@Element{#1}%
+  \draw[->] (\ExpandWithSpaceBetween{\ExpandWithSpaceBetween{\list@Name}{next}}{\list@PrevIndex}.center) -- (\ExpandWithSpaceBetween{\list@Name}{\list@Index});
+  \pgfmathtruncatemacro{\list@Index}{\list@Index + 1}%
+  \drawlist@NextArg
+}
+
+\makeatother