A simple diagram description language.

This was made to fulfill a pretty specific need I had, so it's probably not what you're looking for. However, DOT might be your friend!

yaddl can output DOT or JSON:

yaddl diagram.yaddl diagram.json
yaddl diagram.yaddl diagram.dot

The simplest node you can define looks like this:

= node name

A = followed by a space and the name of the node.

You can then use additional annotations to further describe the node:

• #: A list of comma-separated values, output is a comma-separated string in DOT and a list of strings in JSON.
• /: A pair of values, space-separated. This means the first value should not contain any space. Output is a [a, b] list in JSON and a | b in DOT.
• ': A string.

# is only allowed once per node. Multiple / will result in a list of pairs. Multiple ' will result in a multi-line string. Interleaving / or ' with other annotations is not permitted:

# quux, quuz
/ foo bar
/ baz qux
' Lorem ipsum
' dolor sit
' amet.

this is valid, but this isn't:

/ foo bar
# quux, quuz
/ baz qux
' Lorem ipsum
' dolor sit
' amet.

However, annotations ordering doesn't matter, and this is also valid:

' Lorem ipsum
' dolor sit
' amet.
# quux, quuz
/ foo bar
/ baz qux

A node with every annotation:

= Lorem
# quux, quuz
/ foo bar baz
/ bar foo
' Lorem ipsum
' dolor sit amet.

And the corresponding JSON and DOT outputs:

{
  "edges": [],
  "nodes": [{
    "name": "Lorem",
    "links": [
      ["foo", "bar baz"],
      ["bar", "foo"]
    ],
    "comment": "Lorem ipsum\ndolor sit amet.",
    "tags": ["quux", "quuz"]
  }]
}

digraph G {
  rankdir="LR";
  n0[shape="Mrecord",label="Lorem|quux, quuz|Lorem ipsum\ndolor sit amet.|{bar baz\nfoo\n|foo\nbar\n}"];
}

Output of dot -Tpng node.dot > node.png:

You can define undirected, bidirected and directed edges:

• -- a b: Undirected edge
• <> a b: Bidirected edge
• -> a b: Directed edge, left to right
• <- a b: Directed edge, right to left

Where a and b are node names. If a node name contains spaces, use [node name].

Edges supports comments with '. Usage is the same as ' in nodes.

All nodes must be defined before edges.

Nodes and edges can be separated by zero or more blank lines:

= Node a
' Lorem ipsum.
= Node b

= Node-c
-- [Node a] [Node b]

-> [Node a] Node-c
' foobar
<> Node-c [Node b]

Corresponding JSON and DOT outputs:

{
  "edges": [
      {"direction": "Undirected", "node_b": "Node b", "comment": null, "node_a": "Node a"},
      {"direction": "Directed", "node_b": "Node-c", "comment": "foobar", "node_a": "Node a"},
      {"direction": "Bidirected", "node_b": "Node b", "comment": null, "node_a": "Node-c"}
  ],
  "nodes": [
      {"name": "Node a", "links": [], "comment": "Lorem ipsum.", "tags": []},
      {"name": "Node b", "links": [], "comment": null, "tags": []},
      {"name": "Node-c", "links": [], "comment": null, "tags": []}
  ]
}

digraph G {
  rankdir="LR";
  n0[shape="Mrecord",label="Node a|Lorem ipsum."];
  n1[shape="Mrecord",label="Node b"];
  n2[shape="Mrecord",label="Node-c"];
  n0 -> n1[dir="none",style="dotted"];
  n0 -> n2[label="foobar",dir="forward"];
  n2 -> n1[dir="both",style="bold"];
}

And output of dot -Tpng example.dot > example.png:

Install stack, clone this repo and run stack install.