[bitc-dev] Macro removal rationale

[Michael Weber]

* "Jonathan S. Shapiro" <shap at eros-os.org> [2006-07-20T12:04-0400]:
> In the end, there were three factors:
> 
> 1. My conclusion that building a "clean" macro system (one that does not
> capture the wrong identifiers) is extremely tricky and the result tends
> to be hard to use.

This is a little surprising.  The Scheme community spent quite some on
this, and one would have thought that there is a suitable compromise.

> 2. My observation that there were few good motivating cases for macros
> in a language that supports inlining properly.

Macros for inlining is abuse, I would say.  Proper use of macros
includes creating new syntactic abstractions, basically to make a
language extensible.

Canonical example: how long did Java have to wait for support for
simplified iterators? (Schemers/Lispers would just write a macro for
that, no vendor intervention needed)

> 3. Mark Miller's observation that macros obscure readability by making
> it harder to understand what the code in front of you actually does.

Macros also ensure that, e.g., resources are properly freed, leaving
no room there for errors.  Examples: WITH-OPEN-FILE and friends.


Cheers,
Michael