in reply to Re: Parsing Boolean expressions (hack)
in thread Parsing Boolean expressions

Nice. You can almost parse the expression with the same technique. 
use strict;
use warnings;
use Data::Dump;
my @exprs = (
   "Y = A + (B*C)",
   "Y = A + (B' + (C*D)')",
   "Y = A*(B*(C'+D)')",
);
for my $expr (@exprs) {
   print "$expr\n";
   $expr =~ s/\(/[/g;
   $expr =~ s/\)/],/g;
   $expr =~ s/(\w+|[+*'=])/"$1",/g;
   my @parse = eval $expr;
   dd(\@parse);
   print "\n";
}
__END__
Y = A + (B*C)
["Y", "=", "A", "+", ["B", "*", "C"]]

Y = A + (B' + (C*D)')
["Y", "=", "A", "+", ["B", "'", "+", ["C", "*", "D"], "'"]]

Y = A*(B*(C'+D)')
["Y", "=", "A", "*", ["B", "*", ["C", "'", "+", "D"], "'"]]

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Re^3: Parsing Boolean expressions (hack)
by LanX (Saint) on Apr 23, 2017 at 15:50 UTC
    > You can almost parse the expression with the same technique.

    not really, for a syntax tree you would need an [OP, arg1, arg2] format.

    this

    ["B", "'", "+", ["C", "*", "D"], "'"]]

    doesn't help without further parsing because precedence is still not resolved.

    Rather 

    [ "or", 
    [ "not" , "B" ] , 
    [ "not", 
        [ "and", "C", "D"]
    ] 
]

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    without recursive parsing hard to achieve, I just delegated the hard part to Perl, deliberately ignoring what the OP didn't tell us yet.

    edit

    For instance if the = is not an assignment but a condition, he would want solutions for this equation system...

    (which I could produce at least by brute force for small variable sets, if we had a guarantied format)

    Cheers Rolf
    (addicted to the Perl Programming Language and ☆☆☆☆ :)
    Je suis Charlie!

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[d/l]
[select]
      Yeah, that's why I said "almost." You need to postprocess it a bit to get a proper syntax tree.
[reply]
        > You need to postprocess it a bit to get a proper syntax tree.

        well ... a bit

        Cheers Rolf
        (addicted to the Perl Programming Language and ☆☆☆☆ :)
        Je suis Charlie!

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