Re: Command Languages Versus Programming Languages

On 05.04.2024 01:29, Lawrence D'Oliveiro wrote:

On 4 Apr 2024 11:20:48 GMT, Stefan Ram wrote:
 

And let me tell you, when you start getting into that kind of nested
stuff with not parentheses in view, even the "?:" notation can start
looking pretty darn mysterious to some folks.

 
This is where indentation helps. E.g.
 
    a =
        b ?
            c ? d : e
        : f ?
            g ? h : i
        : j;
 

Indentation generally helps. In above code (in my book) it's not
that clear [from the indentation], e.g. where the last ':' 'else'
belongs to. So I'd have lined the colons up with the respective
'?'. (YMMV.)

Not all languages differentiate (per syntax) a conditional command
from a conditional expression. Here are the two forms supported by
Algol for both, statements and expressions (here the examples are
both depicted for expressions only)

    a :=
        ( b | ( c | d | e )
            | ( f | ( g | h | i )
                  | j ) );

The parenthesis are not used for grouping, but are the alternative
form for IF/THEN/ELSE/FI

    a := IF b
            THEN
                IF c THEN d ELSE e FI
            ELSE
                IF f THEN
                        IF g THEN h ELSE i FI
                     ELSE j FI
            FI

Pick your choice depending on the case (or taste).

Janis