[ash_gti]

They went with a subset of C, its enough to write a working executable. Generally for a introduction tutorial to something as complex as writing a compiler a subset like what they presented in the article is enough to show how all the pieces work together to produce a working compiler.

[mikepurvis]

Yup, for the purposes of a demo like this, a simplified top-to-bottom "vertical slice" is of far more value than total feature coverage.