The slides for the first presentation at the InterSystems Developer Community Meetup in the UK on 17th October 2017. The associated video and audio is at https://www.youtube.com/watch?v=yOxpuzXmCms

1. Dependencies and Complexity
John Murray, Senior Product Engineer

2. Agenda
 Treating Code As Data
 Structure101
 The Architecture of Code
 Tangled Code and the LSM
 Complex Code
 Yuzinji In Operation
 Questions and Comments

3. Mining the Codebase – Treating Code as Data
 From its earliest days George James Software has
developed tools to extract information from code
 Core engine is a table-driven parser written in COS
 Over the years we have developed new parse tables
and ancillary processing to meet specific needs, e.g.
 Y2K conversion projects – finding date handling code
 Global references – locate and transform
 Coding standards – e.g. use of deprecated commands
 Effective communication of such results demands
increasing UI sophistication
 As a small company we seek to leverage other tools
rather than trying to build everything from scratch

4. Structure101
 In 2012 we identified an interesting set of tools
from an Irish software company
 The Structure101 tools were originally created for
Java developers, but later released as a
“generic” variant capable of being extended by
language-specific plug-ins called flavors
 Using our parser technology we created a flavor
for InterSystems class definitions and traditional
COS routines
 We bundle Structure101g Studio plus our flavor
as a tool called Yuzinji
 Structure101g Studio is described by its creators
as an Architecture Development Environment

5. Code Architecture
 Modularity and Connectedness
 Modularity
 Methods
 Classes
 Packages and Package Hierarchy
 Connectedness
 Definitional, e.g.
 extends
 is-of-type
 returns
 Executional, e.g.
 invokes-method
 queries
 calls-label
 jumps-to

6. Tangled Code
 Connectedness leads to dependencies
 Not inherently bad, but need to be understood
 Levelized Structure Map (LSM)
 A key innovation of Structure101
 Positions modules so dependencies point downward
 Modules not used by any other module float to top
 Modules not using any other module sink to bottom
 Other modules find their levels somewhere between
 Dependency cycles (“tangles”) cause upward-
pointing connections
 Can make codebases harder to understand, modify,
extend, test and deploy
 Appearance of new cycles may be evidence of
unwanted architectural degradation

7. Complex Code
 Most software systems can be called “complex”
 Challenge is to manage complexity
 Eliminate / control regions of excessive complexity
 Too much being done in a single module
 Hard to “keep it all in mind”
 Too many possible paths through the module
 Hard to understand / follow
 Hard to test thoroughly
 Metrics
 Lines of Code (LoC)
 McCabe Cyclomatic Complexity (CC) within a
method
 XS – excessive structural complexity

8. Yuzinji in Operation
 Launch from a Caché Studio add-in
 Analyze selected packages or entire Studio project
 Load the results into Structure101g Studio
 Optionally:
 Publish results to a local or remote S101 repository
 View repository using a free web application
 Compare repository snapshots, seeing changes over
time

9. Demo of Yuzinji

10. Yuzinji Beyond Complexity and Dependencies
 With Structure101g Studio you can do more, e.g.
 Define your application architecture
 Communicate this to developers via diagrams
 Detect violations of the defined architecture
 Model a set of refactoring steps, in order to
investigate their effect on complexity
 Provide todo lists to drive actual refactoring of code

11. Further Info
 http://georgejames.com
 http://structure101.com
 Visit George James Software at the Partner
Pavilion