Design Requirements

Accepted Requirements

• Colocate option specification: names and aliases, doc string, type default values, size of array (repetition count)
• Error checking as early as possible
• Merging multiple configurations with conflict handling per option
• Positional arguments
• Arguments with multiple parameters, e.g. arrays on the command line
• Explicit refresh of data source
• User defined types, e.g. The Garland Date Time
• Dynamic/run-time configuration of options in the ParameterSpec. Compile time addition of new types.
• Custom data sources
• At least one command-line data source built in to library (should this be program options?)
• Data sources return tree-like data
• API will permit substitution rules

##Rejected Requirements

• Conflict resolution between options (out of library scope
• Static type checking (too difficult, usability issues, collides with dynamic changes, also Michal's library https://github.com/griwes/ReaverLib already provides this)
• Lazy data fetching from data source (conflict with "error checking as early as possible" requirement)
• Non-string keys (reserved for 2.0)