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Re^3: Left-associative binary operators in Parse::RecDescent

by jryan (Vicar)
on Dec 14, 2004 at 23:15 UTC ( #414890=note: print w/replies, xml ) Need Help??

in reply to Re^2: Left-associative binary operators in Parse::RecDescent
in thread Left-associative binary operators in Parse::RecDescent

Yeah, that's a good point. You'll need to get rid of the left-recursion. To do that, you'd need to get rid of binary_op and subexpression in your subexpression rule. Next, you'll need to factor out all of the paren stuff into a single rule, and then use that rule within the binary_op rule instead of subexpression. Here's an example:

paren: '(' binary_op ')' { \$item [2] } # parens belong here, and o +nly here! | subexpression subexpression: function_call | var | literal | <error> binary_op : paren (op paren { [ \@item[1..2] ] })(s?) # any +parenned expression will sink down here { [ \$item[1], map { \@\$_ } \@{\$item[2]} ] }

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[Discipulus]: mah, winbuntu 10...
[marto]: whent he boys start school I'll build myself as new machine, ryzen based
[Corion]: marto: That's cool! I think my (home) desktop spends 30 seconds in the BIOS...
[Corion]: marto: Heh - currently they seem promising, but I think I'll stay with nVidia+Intel for the time being, as I've been bitten too often by bad AMD drivers
Discipulus is (still?) not a big fan of notepad++
[marto]: Corion, I think in the past this was a big problem for them. GPU driver wise the improve all the time. I use the open source drivers on my machine (old R9 270, 2GB) and had no problems
[Discipulus]: is not the problem with new hardware?
[marto]: notepad++ ticks all the boxes for me, it's a fine line between just enough, and bloat, in editors for me :P
[marto]: Discipulus]: less so than the modern intel CPUs
[marto]: also, AMD are faster at fixing the CPU microcode it would seem

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