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Newsgroups: comp.lang.ada
Date: Wed, 20 Jun 2018 01:33:03 -0700 (PDT)
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Subject: Re: Why are Ada compilers difficult to write ?
From: gautier_niouzes@hotmail.com
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Xref: reader02.eternal-september.org comp.lang.ada:53192
Date: 2018-06-20T01:33:03-07:00
List-Id: <comp.lang.ada>

The challenges are roughly the features that make the programmer's life easier: the burden is moved to the compiler writers.
You can begin with unconstrained types whose sizes are not known at compile-time. Then variables of unconstrained types which are sized on initialization. Then add exceptions. Add packages. Then generics (not just macros).

For the fun of it, you find a full Pascal-in-Pascal here:
http://www.moorecad.com/standardpascal/pascals.pas

...and a remote descendant here (HAC, +/- a Pascal with Ada syntax):
https://sourceforge.net/projects/hacadacompiler/
- none of the mentioned goodies like unconstrained types are present in HAC so far...