Re^3: cross scope gotos?

You can't jump to a label out of the current or previous frames!

I think that's (currently) an over statement:

perl -le"goto loop; $x=0; if( $x ){  while(1){ loop: print 'hi' } }"
[download]

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Re^4: cross scope gotos? by LanX (Saint) on Apr 06, 2010 at 16:09 UTC
> I think that's (currently) an over statement: nope, `while` has a proper block but not a proper "frame" like `foreach` or `sub`s. (I read somewhere that foreach has internally a frame, but no time to search now...) But the confusion is understandable, that's why I started the thread. Cheers Rolf	[reply] [d/l] [select]
Re^5: cross scope gotos? by ikegami (Patriarch) on Apr 06, 2010 at 16:36 UTC
Counter-example: `perl -le"goto loop; $x=0; if( $x ){ for(;;){ loop: print 'hi' } }"` [download] Update: Ah, you did say foreach `>perl -le"goto loop; $x=0; if( $x ){ for(1){ loop: print 'hi' } }" Can't "goto" into the middle of a foreach loop at -e line 1.` [download] Mind you, it's not really related to stack frames. Any required frame is created by `goto`. Since it's an explicit check for OP_ENTERITER, it appears more of a question of there not being any sensible way of initialising the iterator of the iterated loop into which you are jumping. `/* push wanted frames / if (enterops && enterops[1]) { OP * const oldop = PL_op; ix = enterops[1]->op_type == OP_ENTER && in_block ? 2 : 1; for (; enterops[ix]; ix++) { PL_op = enterops[ix]; /* Eventually we may want to stack the needed arguments * for each op. For now, we punt on the hard ones. / if (PL_op->op_type == OP_ENTERITER) DIE(aTHX_ "Can't \"goto\" into the middle of a foreach loo +p"); CALL_FPTR(PL_op->op_ppaddr)(aTHX); } PL_op = oldop; }` [download] Update*: Improved phrasing of last paragraph and added supporting code.	[reply] [d/l] [select]
Re^6: cross scope gotos? by LanX (Saint) on Apr 06, 2010 at 21:12 UTC
Well I don't know anymore where I read the word "frame" in connection with foreach-loops. The glossary of the docs is often far too fuzzy to justify a long discussion... Anyway grepping through the docs produced `perldiag.pod: (P) The foreach iterator got called in a non-loop context frame.` (I didn't say "call frame") But the C code is quite hard for me too understand without more conceptual basics... which are fuzzy ... Cheers Rolf	[reply]


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