[Cfp-interest] further revisions to syntax discussion

[David Hough CFP]

I incorporated some other bits to make it more self-contained
and self-explanatory, I hope.

http://www.validlab.com/cfp/

is updated.

Here are the diffs:

7,8d6
< BACKGROUND:
< 
47,52c45,46
< Although existing standard C has support for detecting exception flags
< and handling SIGFPE, that's like saying that Fortran-77 supports a heap.
< It is true that any competent Fortran-77 programmer could program blank 
< common to be used like a heap.    It is also true that the result is
< difficult to write correctly and even harder to read.    C provides malloc
< and free instead.    Fortran-90 eventually caught up to C in this respect.
---
> The general programming paradigm as it might be naturally
> expressed in many languages is
54,60d47
< SEMANTICS:
< 
< So from the higher point of view of an applications programmer, rather than
< the lower point of view of a system implementer,
< the common programming exception-handling paradigm is naturally
< expressed in many languages in this fashion:
< 
90,116d76
< IEEE 754 specifies default exception handling, but if the default were
< always satisfactory then it wouldn't be exceptional.   By definition,
< an exception can't be handled the same way in every situation in which it
< might arise.    So alternate exception handling must be specified from
< time to time, more often in code that is intended to be as fast as possible
< in the normal case, but as robust as possible when exceptions arise which
< are not normal, but are not so rare that they can be ignored.
< So some desirable attributes of exception handling include
< 
< 1) the normal case should be as fast as possible
< 2) the exceptional case should be detected as quickly as possible
< 3) the application programmer can understand the exception and its handling
<    in terms that do not depend on the specific hardware and operating system, 
<    so the syntax and semantics are portable
< 4) the compiler/operating system/hardware figure out the most efficient
<    way to implement the intended semantics on a particular platform,
<    rather than leaving that burden on the application programmer
< 
< SYNTAX:
< 
< There are many different ways to express the syntax.    They all have
< in common a need to specify
< 
< 1) the normal case code that the exception handling applies to
< 2) the exceptions to be handled specially
< 3) the exception case code to be executed when those exceptions arise
<