Some thoughts on the 'reveal' operator

[Ka-Ping Yee]

On Mon, 27 Sep 1999, Mark S. Miller wrote:
> 
> As long as we're talking syntax design, I'll go ahead and revive an old 
> question: Ping especially has long advocated that E adopt Python's use of 
> indentation rather than curly brackets for block structure.

That's a bit stronger than i would have described my position.  I do
indeed like the visual simplicity of Python which is due to the lack
of curly braces, but the argument that E needs braces to be a decent
command-line language seems quite sound.  Although Python programs
are beautiful to read, they're troublesome to enter interactively.

> My counter-argument has been we tried that in Joule, but got killed by tab 
> ambiguity.  Most everyone agrees that text files should be considered to 
> have a tab stop every N positions, but many passionately insist (as I do) 
> that N is 8, while others insist with equal passion that N is 4.

I passionately insist that tab characters be eradicated from all
source files, precisely to avoid this ambiguity.  If i use spaces
everywhere i can be sure that my code will be readable independent
of where it appears.

> (Note that I also believe and advocate that one should indent one's code to 
> 4-space indentation boundaries, and that editors should interpret the tab 
> key on the keyboard to position the cursor to the next indentation 
> boundaries.  These issues are not coupled.)

I agree with both of the above.  For vim users:

    :set ai et sw=4 ts=8

> Except that Python works.  What does it do?

Python interprets tabs in the "normal" Unix way, i.e. move to the next
tab stop where tab stops are in columns { 1 + 8k, k in Z }.  Most
Python programmers indent four spaces and either avoid tabs or use
8-column tabs.

> Alternatively, how about if tab was simply not considered as valid 
> character to be present in E source code?

Interesting!  You know, you might get lynched for doing this, but
i kind of like it.


-- ?!ng

"Don't worry about people stealing an idea.  If it's original, you'll
have to jam it down their throats."
    -- Howard Aiken