How reasonable is it to dive any to this and treat the Pascal as pseudocode so as to implement it in another language? Or would one be better off just using something like freepascal.org?
For the excellent introductory book "Compiler Construction" by Niklaus Wirth, you could find compilers for the implementation language at http://oberon07.com/compilers.xhtml.
If you have a JVM installed, you could use oberonc[0]. I have a local branch where I test that each release of the compiler can compile and run the examples in that book.
I guess what I'm asking is if Oberon-0 is a subset of Oberon-7, which oberonc seems to implement. Do you think it is possible to implement Oberon-0 in itself ?
Oberon-0 is too limited to easily bootstrap itself. I wrote oberonc first in Java and then I rewrote it in Oberon-07 for the final bootstrap step.
Oberon-0 is a toy subset of the full Oberon-07 language.
Yes, you can write small Oberon-0 programs and compile them with an Oberon-07 compiler, but it is simpler to just use the Oberon-0 compiler from the repo above.
I was taught compiler construction by the books like that. In my opinion they do more damage than good.
A proposed adhoc parser without an intermediate representation is a sure way to create an unnecessary mess in reader's head. Somewhat understandable given the technical limitations of those days, but still the authors could do a better job there.
Dragon Book (Compilers: Principles, Techniques, and Tools) and "Compiler Construction" by Niklaus Wirth are much more sensible choices.