Re^2: [DSL] disabling packages in Perl?

> like "or" and "and" short-circuiting:

Thanks, I'm fully aware of this! :)

My initial plan was to patch B::Deparse in a way to take the op-tree of the code-block and to produce SQL instead of Perl (or rather a semantically correct intermediate Perl representation which produces SQL)

> flattening of "(" and ")"

likewise, true lists are flattened but precedence is still visible in the op-tree

BUT for the moment I'm rather inclined to create subs OR() and AND() for a quick prototype.

That is taking multiple expressions after a prefixed operator.

 
WHERE {
   OR ( number EQ 3, 
        AND ( 
            customer LIKE '%...%',
            name     IN   qw/John Jane/,  
        )
      )
}
[download]

Thats not really much overhead, because when mixing AND and OR parens should always be applied to highlight precedence.

I'm very busy ATM but I'll show a proof of concept after next weekend.

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

Je suis Charlie!}

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Re^3: [DSL] disabling packages in Perl? by mlawren (Sexton) on Apr 19, 2016 at 21:14 UTC
> Thats not really much overhead, because when mixing AND and OR parens should always be applied to highlight precedence. I would agree about the parens but there is a certain cognitive overhead in disassembling (or creating) the reverse polish notation which I have always shied away from. In the end for complicated expressions I think (I would have to check as it's been a while) I went for a mix of arrayrefs and hashrefs (implicit AND): `select => [qw/expr1 expr2/], from => 'table', where => [ { number => 3 }, OR, { 'customer LIKE' => '%...%', name => [qw/John Jane/] }, },` [download] I'm looking forward to seeing what you come up with. Please post it!	[reply] [d/l]

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Re^3: [DSL] disabling packages in Perl?
by mlawren (Sexton) on Apr 19, 2016 at 21:14 UTC

> Thats not really much overhead, because when mixing AND and OR parens should always be applied to highlight precedence.

I would agree about the parens but there is a certain cognitive overhead in disassembling (or creating) the reverse polish notation which I have always shied away from. In the end for complicated expressions I think (I would have to check as it's been a while) I went for a mix of arrayrefs and hashrefs (implicit AND):

    select => [qw/expr1 expr2/],
    from   => 'table',
    where  => [
        { number => 3 }, OR,
        { 'customer LIKE' => '%...%', name => [qw/John Jane/] },
    },
[download]

I'm looking forward to seeing what you come up with. Please post it!

[reply]
[d/l]