This document discusses first time right coding, which involves writing code that compiles without errors from the first attempt. It recommends setting up automatic compilation when files are saved or typed to catch errors early. This prevents wasting time fixing errors and avoids checking in broken code. Various IDE tools are mentioned that can help with incremental compilation and catching syntax, type, and other errors at compile time rather than later.

1. First time right coding
how to stop wasting time
fixing compiler errors
Dr. Ir. Philippe Faes

2. http://xkcd.com/303/

3. Overview
● First time right coding
○ what
○ why
● Protect yourself
● Don’t waste time / money
○ catching bugs early
● How to catch bugs early
○ Types of things that you can find at type-time
● [Demo]
● What to do next?

4. What is first time right coding?
● Each commit (in version control) can be
compiled and executed.
● Every project has
exactly zero syntax errors at all times.
● Never save files that will not compile

5. Why you need tools?
If you don’t make mistakes, you spend
too much time
proofreading your code.

6. Why?
The only purpose
of compilation and simulation is to
validate behavior.
Not to find syntax errors.

7. Protect yourself from
● evil colleagues who check in broken code
● looking bad in front of your colleagues
● wasting time fixing compilation errors

8. Protect yourself from
evil colleagues
My former colleague —let’s call him “John”—
used to break the build all the time.
He always insisted it was not his fault.

9. Do you know how silly you look
when your file is missing a semicolon?
;
Protect yourself
from public shame.

10. Don’t waste time / money

11. Catching defects earlier
is cheaper

12. Catching defects earlier
is much cheaper

13. How to fix this
options:
4. run build scripts before you commit
3. regularly run your (incremental) build scripts
2. automatically compile when you save
1. compile while you type

14. Your own (incremental) build
Custom scripts
● bash, Tcl, Python, ...
Incremental building:
● Makefile

15. Works in:
● standard Eclipse
● Sigasi Free Starter Edition
● (and maybe in other tools too)
Use custom builder,
with MarkerManager plugin
Save-time compilation

16. Type-time
Standard technology in many software IDEs
For VHDL:
Available in Sigasi Pro,
with better (linting) checks in Sigasi Premium

17. Types of errors
that can be caught
● Syntax errors (obviously)
● Datatype errors
● Style guide violations
● Even some kind of elaboration errors!
○ check bus widths, even using symbolic lengths
(live demo)

18. What to do next?
1. compile before you commit
2. compile each time you save
3. compile before you save