Re^8: Split tab-separated file into separate files, based on column name ( Operator overloading )

in reply to Re^7: Split tab-separated file into separate files, based on column name ( Operator overloading )
in thread Split tab-separated file into separate files, based on column name

A good example for overloading are set operations, because the logic is "compatible".

X * Y intersection
X + Y join
X - Y difference
- X complement

I don't see how the logic is compatible, unary - as complement means X - Y is different from X + (-Y). And there's just no relation between * and + anymore. At least with + for concatenation (which I already don't like much), you can have STRING * 3 to be equivalent to STRING + STRING + STRING.

And actually now that I think of it, the best operator to overload to append to a file is .=. With the dot you have both the append and string semantic, and the = makes it ok for the operation to have an effect on the left operand. And it makes chaining more consistent:
file("path") .= "First string" . "Second string";

Comment on Re^8: Split tab-separated file into separate files, based on column name ( Operator overloading ) Select or Download Code

Replies are listed 'Best First'.
Re^9: Split tab-separated file into separate files, based on column name ( Operator overloading ) by LanX (Saint) on Aug 27, 2020 at 12:50 UTC
> I don't see how the logic is compatible Set operations have a natural analogy to Boolean operations. And in mathematics and CS `and` and `or` are often replaced with `` and `+` notations, especially in pre-LaTeX documents. That's because the truth tables are the same `/AND 0 1 0 0 0 1 0 1 +/OR 0 1 0 0 1 1 1 2 (2 is true here)` [download] Arithmetic operators `+ - * /` are also "close" in precedence, associativity and context (see `perlop` ) and the grouping rules are well known. Furthermore is comparison with `< > => <=` obvious here. Also the duplicity of `==` and `eq` for comparison comes handy (same "set object" or same "set elements") > STRING 3 to be equivalent to STRING + STRING + STRING.* not sure what you mean set elements are unique, if you refer to power-sets the cross operator `x` or power `**` may be the better choice. Cheers Rolf _{(addicted to the Perl Programming Language :) Wikisyntax for the Monastery}	[reply] [d/l] [select]

Replies are listed 'Best First'.

Re^9: Split tab-separated file into separate files, based on column name ( Operator overloading )
by LanX (Saint) on Aug 27, 2020 at 12:50 UTC

> I don't see how the logic is compatible

Set operations have a natural analogy to Boolean operations.

And in mathematics and CS and and or are often replaced with * and + notations, especially in pre-LaTeX documents.

That's because the truth tables are the same

*/AND
  0 1
0 0 0
1 0 1

+/OR
  0 1
0 0 1
1 1 2 (2 is true here)
[download]

Arithmetic operators + - * / are also "close" in precedence, associativity and context (see perlop ) and the grouping rules are well known.

Furthermore is comparison with < > => <= obvious here.

Also the duplicity of == and eq for comparison comes handy (same "set object" or same "set elements")

> STRING * 3 to be equivalent to STRING + STRING + STRING.

not sure what you mean set elements are unique, if you refer to power-sets the cross operator x or power ** may be the better choice.

Cheers Rolf
_{(addicted to the Perl Programming Language :)

Wikisyntax for the Monastery}

[reply]
[d/l]
[select]

In Section Seekers of Perl Wisdom