Saturday 23 June 2018, was a sunny day in Milan. The ideal day to close yourself in Milano Bicocca University with many equally nerdy fellow programmers to attend the Italian C++ conference.
I discovered this conference, now in its 3rd edition, by chance, skimming through my neverending queue of unread tweets. A friend of mine and C++ guru twitted about this, so I bookmarked the website and as soon as this year edition was announced I was one of the first to register.
Also it is worth noting that this conference is free (as in beer), lasts a full day and includes the lunch. Talks are interesting and the conference is organized in two tracks with a single starting keynote and a single closing speech.
Although free, there are famous guests – last year Bartosz Milewski – quite a famous functional programmer and category algebra expert – held a speech about C++ and functional programming; this year the keynote was by Peter Sommerlad — C++ expert and member of the C++ ISO committee.
As usual my good intentions are to write and publish about each single talk I attended to.
Comparison with other conferences I attended, such as Scala Days, Scala Italy and Lambda World, is natural, although not always fair – ++it is completely free, while others come to a price (not light in case of Scala Days). I couldn’t fail to notice that age on average was older here than in the functional world. I won’t try an interpretation, but there could be more than one.
But, enough with babbling, let’s start with the keynote (based on my notes taken during the talk, errors or misunderstandings are just mine). You can find Peter Somerlad’s slides here. My comments at the end.
A – B – C : Agile, BMW, C++
In this talk prof. Somerlad basically tells about his professional career, era by era, providing a short list of lessons learned for each period.
He started programming on a HP pocket calculator. This device had some 50 steps of program instruction and no graphics whatsoever. Also TI calculators were more widespread at time, so he had to translate programs from one programming language to another one. Although very similar (they were all stack based) each calculator had some peculiarities.
One program he developed for fun was a ballistic simulation – define a force and a direction to fire a bullet that has to avoid a wall and hit a target. As said, the pocket gizmo has no graphics, but years later, the very same idea was re-instantiated with some graphics and sounds to become… Angry Birds.
- Mentally execute code – there was no debugger;
- Using the stack;
- Reading foreign code (to translate from TI to HP);
- Porting code;
- Old simple ideas reamain useful.
The first home computer was a ZX Spectrum – an 8bits computer with rubbery keyboard that connected to a TV set and used a cassette recorder as mass storage. Each key was decorated with several keyword beside the standard letter and symbol you normally find on a key. When pressing a key, depending on the context, one of such a keyword appeared on the screen – automatically typed for you. Context was determined by pressing two shift keys. The correct combo produced the required effect.
At school he worked on a mainframe, that had a curious assembly language. Notable one instruction, by exploiting an indirection bit, could be used to create an infinite loop. He and another one student tried the instruction and the mainframe froze. After few seconds an angry System Administrator entered the room, asking them to quit what they were doing.
- Basic, Z80 assembly and machine code, Pascal;
- Keyboard shortcuts and meta layout;
- Patience (loading from tape takes forever);
- Dealing with errors from hardware.
In 1985 he landed his first job where he had to write a kind of customer management application on an Apple IIe. Now the software had to be professional and one requirement was that a cat could walk on the keyboard without causing a crash of the application. At times no commoditized databases were available and the few db engines available were very expensive. Since the Apple IIe had floppy discs, they may have to merge the two databases on two discs. The solution is to employ a merge sort, so he took the book from Niklaus Wirth “Data+Functions=Algorithms” and copied the merge sort implementation. Unfortunately the merge sort algorithm on the book was not stable, so Peter had to rewrite it from scratch.
Implementing the DB was quite a nightmare for many technical constraints – computer memory, mass storage size and computing power. The PC was an IBM with MS-DOS 1.x. This version had no directories. The Pascal language had no dynamic strings – they had to be statically sized.
As computer technology progressed he switched to a 386 compatible and turned to minix. During this period, Peter used PMate – an editor that sported macros, so that statement frames could be automatically generated.
- do not trust programming books and commercial libraries;
- before putting code in your book, always compile and test it;
- programming should be supported by fast and powerful editor;
- you should not need to type all of your code;
- generic data driven solution make code simpler
- automate tests.
1987 C and Unix courses
During this period Peter started teaching classes about C and Unix. In this classes shell, system programming and C were taught. Also he had to teach how to unlearn things to Cobol Programmers.
In 1988 he wrote some C guidelines – some are still actual today:
- a function is too long if it does not fit in a 80×24 terminal; functions with longer code tells a failure in teaching software engineering.
- a function should not take more than 3-5 parameters, if you need more, then you have to logically group them in struct. Windows API had function with 7 or more parameters, that why Peter swore never to program this OS.
- Everything is an int, unless it is a pointer or a double. (The reason why we need to use the typename keyword today is a legacy of this choice made by K&R).
- Program abstract data types using opaque structs and pointers.
- Do not use scanf() ever in production code, use sscanf() instead and check its result.
- K&R C, Unix, sh, awk, sed, vi, nroff, make, lex, yacc,…
- You learn the most by teaching.
- One can program in fortran/basic/cobol in any language.
- abstraction, layering, cohesion.
- the power of plain text, regexp, pipelines and scripting. Searching log files for what went wrong.
In 1989 Peter graduated. His master thesis was about a Modula-2 frontend for the Amsterdam Compiler Kit. In this year, also the first experiments with C++ using the Zortech C++ compiler. Writing code with this environment was quite intensive since any error in the code caused the whole machine to die. These were days before Protected Memory.
- Compilers and AST with polymorphic nodes (polymorphism via union);
- Virtual Machine Languages (p-code, em-code). Java bytecode is very close to em-code;
- more RAM and CPU power make compilation much faster;
- ADT works even within a compile;
- lex and yacc can be used in practice.
Conscript at Bundenswehr (the German Army). Peter worked in the Computer Center, on systems for Radar detection and analysis. This was quite a travel back in time. The computer was an 18 bits with core memory, switches to input bits into the main memory and tape for mass storage.
Also Peter found another computer history milestone – the VT100 terminal. This terminal defined what ANSI escape codes are today.
The language used for programming the system was Jovial a mix of pascal and algol that was later replaced by Ada.
- Computer and software history can be interesting;
- Even hardware can be used beyond its expected lifetime;
- source control is important (and copying floppy disc is not source control)
In 1990 he landed a job at Siemens and started working in OO programming environment. Here he worked with Erich Gamma and Andrè Weinard [NdM: I tried to look up this but haven’t found anything relevant, maybe I got the name wrong].
The system Peter was working at was a framework for C++ written in C++, named OOPU, intended to replace TOROS_OBER a C macro based OO system used for car diagnostic computer. Unfortunately OOPU was killed by internal politics. The reason was that a single programming environment had to be used across several business units, and other business units didn’t want to pay for it.
In this context Peter wrote an object inspector, named OBER, that showed the relations among objects (this was before DDD was invented). From architectural point of view this application sported an UI separated from the backend.
In 1991 Peter wrote the first C++ guidelines, although some are still applicable, many are obsolete because the language evolved and things can be done better.
1993 was the year of the PLoP (Pattern Languages of Programming), this was still before the Gang of Four Book. In this conferences many opportunities wer to learn and understand architecture by trying to explain patterns.
1995 is the year of GoF. The most important design pattern are:
Do not use the singleton since C++ has no fixed sequence of initialization. If you need singleton, think about design first. If you need globals, just use globals [NdM, I understand that singleton has some problems, but I don’t see what is the alternatives – globals lacks of encapsulation].
In PLoPs and EuroPLoP, patterns had a community, where knowledge was shared, and it offerd an environment to try out ides. Discussing how stuff has to be written and why.
With other participant of the PLoP/EuroPLoP, Peter wrote the book POSA – Pattern Oriented Software Architecture. This is less famous than Design Pattern by the Gang of Four, but tackled the same matter.
Layers vs. Tiers -Layers are different level of abstraction , you can swap a layer implementation with another; while in tiers, functionality spread on multiple tiers, all the the same level of abstraction employing different technologies.
Using layers the team can specialize, while using tiers the team needs to know everything.
Good abstraction is a skill. Too many layers are a problem if layers do nothing but pass values.
- A prophet has no honor in his own country – get out to be heard;
- good patterns require several rewrites;
- Sharing teaches you to become a better author;
- Get a good copy editor, when publishing;
- Network to learn – attend and speak at conferences;
- most important part of a conference are the breaks.
In 1997 he moved to Switzerland to take the job of Erich Gamma, more precisely to work on a small server framework www.coast-project.org. While in charge Peter extended and improved the library and developed C++ Unit Test and test automation in doing so. He delivered high-quality solutions using Agile Software development and Wiki wiki web.
In these years Peter came to some interesting conclusions about high quality software. First high quality leads to better developer and better retainment of those developer. Unfortunately high quality leads to canceled maintenance contracts. If nothing goes wrong, the customer doesn’t see the point in paying for something that is never used.
Also, counter intuitively, high quality leads to less business opportunities. Since the contacts between customer and developer are minimal and usually don’t escalate to top level management. So the developer has less chance to meet and know the decision makers of the customer company.
Also CUTE – the test environment – has been created to replace macro-ish test.
- to advance you need to take risks;
- do not be shy to use your network;
- if you can not change your organization change your organization;
- leading a team and evolving it is gratifying
- producing software with a superior quality might be bad for business
- working software lives longer than intended.
1998 and Agile Development. It became evident that following rituals is not adhering to values. You can do all the scrum rituals, but without committing to its values. When doing agile the most important things are:
- Unit Tests and TDD;
- Refactoring and Simple Design;
- Rhythm and feedback, i.e. thinking about what you do and what you achieve;
- Open and honest communication.
- be self sufficient, but accept and appreciate help;
- as a patient you are responsible for yourself.
Since 2004, Peter started teaching agile and continued teaching C++, concurrent and network programming. Also started working on IDE and tools, with the goal to eliminate bad software.
In 2005 many people thought that refactoring tool for C++ was impossible to write. Peter worked to prove them wrong, and Cevelop is the result.
[NdM: The talk ran out of time about now.]
Despite being sympathetic with Peter, since we shared so much in terms of computer history, programming and software engineering, I have to admit that his talk didn’t leave me with much. Also I fail to see the lack of some self-celebration. Maybe the most interesting thought was that quality software leads to less business. The rest of the talk was enjoyable, but I couldn’t see the connection with C++ or the future (or the history) of this language.