railroad_dsl

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A small DSL to generate syntax diagrams using this library.

Some examples

• {...} is a horizontal stack of connected elements
• [...] is a vertical sequence of connected elements
• <...> is a choice of multiple options, exactly one of which has to be picked
• "foobar" is a terminal
• 'foobar' is a non-terminal
• `foobar` is a comment
• ...? is an optional element
• ...*... is a repeated element
• ! is the empty element

Quotes (and backslashes) can be escaped using backslashes.

For example:

{["CONSTRAINT" "name"]?,
 <["PRIMARY" "KEY" <!, "ASC", "DESC"> 'conflict-clause' <!, "AUTOINCREMENT">],
  ["NOT" "NULL" 'conflict-clause'],
  ["UNIQUE" 'conflict-clause'],
  ["CHECK" "(" 'expr' ")"],
  ["DEFAULT" <'signed-number', 'literal-value', ["(" 'expr' ")"]>],
  ["COLLATE" "collation-name"],
  'foreign-key-clause'>}