uMF: micro modelling framework (uMF)

uMF is a minimal, yet powerful modeling framework (aka DSL workbench) based on the Lua language. It permits defining and validating models by means of placing structural, composable contraints on Lua types.

Features

DSL defininition by defining constraints on Lua data structures
lightweight OO support to define typed tables
predefined constraints are extensible and configurable
easy definition of new constraints
constraints can be composed
localized error reporting during model checking

Simple Example

A constraint is model using a umf Spec. Multiple predefined specs are available.

Defining a 3D vector of the form { x=1, y=0, z=0 } can be achieved with the following Spec:

Vector3DSpec = umf.TableSpec{
   name = 'Vector3D',
   sealed = 'both',
   dict = {
	  x = umf.NumberSpec{},
	  y = umf.NumberSpec{},
	  z = umf.NumberSpec{},
   },
}

Defining Model Elements

Defining Constraints

Basic transformations

These functions provide additional model transformations that may be applied after successfull validation.

NOT implemented!

Resolving references

resolve(src-field, tgt-field, model, [src-filter-fun], [tgt-filter-fun])

Behavior:

For each table (or object) in the model, the function will search for tables (or objects) whos value of tgt-field matches that of src-field. If such a match is found, the value of src-field of this object is modified to directly reference the target object.

If the optional src-filter-fun and/or tgt-filter-fun predicate functions are provided, the resolving will only take place if these functions when applied to the respective table (or objects) return true.

matching rules:

absolute if starts with a /
relative without slash
relative parent references ../ (only if

Creating parent links

create_parent_ref()

Generic traversal

Code generation

Pitfalls

It's a common pitfall to assign a spec class instead of an instance when defining a constraint model.

Future work

json-schema import/export
ECore import/export

Known issues

Problem

Obscure error: "umf.lua:128: instance_of: second argument not an instance" if a spec is declared as a plain table instead of a Spec instance.

Solution

Extend instance_of to return an error msg instead of assert'ing. Better: it's caused by an invalid spec, hence the spec should be validated against against the metaspec.

Acknowledgement

The research leading to these results has received funding from the European Community's Seventh Framework Programme (FP7/2007-2013) under grant agreement no. FP7-ICT-231940-BRICS (Best Practice in Robotics)

haianos/uMF