Schematique

Graphviz preprocessor for simpler flowcharting

Aims

In order of importance/general interest:

automate word-wrap
simplify syntax (for some definitions of "simplify"), especially for tables.
enable a powerful "format presets" system. (e.g. tag a node with {objection} for a red border, tag it with {support} for a green border, etc.)

Requirements

Schematique requires:

GraphViz (for all the real work)
Inkscape (for SVG to PDF conversion)

Word-wrapping

This is controlled through the variable LINE_LENGTH, which is currently set at 40 characters. The parser adds a <BR/> after every 40 (or whatever you want) characters. You can put in your own breaks manually and it works to complement them nicely (i.e. it starts counting again if it encounters a break already in the text).

Word-wrapping is also performed on lines in tables. A basic variable (TABLE_LINE_BASE) is used, but multiplied according to the number of columns the cell spans.

The Syntax

Customisable presets

for nodes: node_name [label = "Lots of nice text." {default}]
- becomes: node_name [label = "Lots of nice text.", color = blue, shape = rectangle, style = rounded, penwidth = 3, style = solid]
for edges: node1 -> node2 {{default}}
- becomes: node1 -> node2 [color = blue, style = solid]

These presets can be customised in the flowchart_keywords_list.rb file.

Tables in Nodes

It is hard to have a syntax for tables that is both powerful (allowing for both colspan and rowspan) and markdown-like in its user-friendliness. This is an attempt to strike a balance between the two.

Tables open with a line containing the node_name, followed in the next line by <TABLE. Formatting like borders is handled using presets, except for color.
The table is closed with </TABLE> (nothing more is needed --- it is handled through presets).
Think in terms of rows rather than columns.
- each row is opened with +== and closed with ==+
- for convenience and readability, every row boundary except for the top and bottom of the table is indicated by ==++==.

The syntax permits colspan:

cells are opened by + followed either by hyphens - or pipe symbols (|).
- +- opens a cell spanning one column
- +||| opens a cell spanning three columns
- cells are closed with the mirror-image of their opening: e.g. -+ or |||+

Here is a fairly simple table. The syntax is not fully intuitive, but better than trying to write HTML tables.

Three_things 
<TABLE COLOR="BLUE">
+==
  +||| BORDER="0">A List of Three Things|||+
==++==
  +->First Thing-+
  +->Second Thing-+
  +->Third Thing-+
==+
</TABLE>

We can also create tables with row-span:

Here, we indicate the number of rows the cell spans with the number of - after the +
- +--- spans three rows.
Again, we close the cell with the mirror-image of the opening: ---+

Once again, the table is not immediately intuitive, but doesn't get in the way too much.

Four_Things
<TABLE COLOR="FORESTGREEN">
+==
  +|| BORDER="0">Four Things||+
==++==
  +---->Here are four things----+
  +->The first thing-+
==++==
  +->The second thing-+
==++==
  +->The third thing-+
==++==
  +->The fourth thing-+
==+
</TABLE>