diff options
| -rw-r--r-- | embed.fnc | 1 | ||||
| -rw-r--r-- | embed.h | 1 | ||||
| -rw-r--r-- | pod/perldiag.pod | 17 | ||||
| -rw-r--r-- | pod/perlfunc.pod | 5 | ||||
| -rw-r--r-- | pod/perlsyn.pod | 19 | ||||
| -rw-r--r-- | pp_ctl.c | 39 | ||||
| -rw-r--r-- | proto.h | 3 | ||||
| -rw-r--r-- | t/lib/croak/pp_ctl | 2 | ||||
| -rw-r--r-- | t/op/when.t | 29 |
9 files changed, 53 insertions, 63 deletions
@@ -2227,7 +2227,6 @@ sR |OP* |dofindlabel |NN OP *o|NN const char *label|STRLEN len \ s |MAGIC *|doparseform |NN SV *sv snR |bool |num_overflow |NV value|I32 fldsize|I32 frcsize sR |I32 |dopoptoeval |I32 startingblock -sR |I32 |dopoptogivenfor|I32 startingblock sR |I32 |dopoptolabel |NN const char *label|STRLEN len|U32 flags sR |I32 |dopoptoloop |I32 startingblock sR |I32 |dopoptosub_at |NN const PERL_CONTEXT* cxstk|I32 startingblock @@ -1716,7 +1716,6 @@ #define dofindlabel(a,b,c,d,e,f) S_dofindlabel(aTHX_ a,b,c,d,e,f) #define doparseform(a) S_doparseform(aTHX_ a) #define dopoptoeval(a) S_dopoptoeval(aTHX_ a) -#define dopoptogivenfor(a) S_dopoptogivenfor(aTHX_ a) #define dopoptolabel(a,b,c) S_dopoptolabel(aTHX_ a,b,c) #define dopoptoloop(a) S_dopoptoloop(aTHX_ a) #define dopoptosub_at(a,b) S_dopoptosub_at(aTHX_ a,b) diff --git a/pod/perldiag.pod b/pod/perldiag.pod index a9a503e16d..005147536f 100644 --- a/pod/perldiag.pod +++ b/pod/perldiag.pod @@ -1076,6 +1076,16 @@ usually double the curlies to get the same effect though, because the inner curlies will be considered a block that loops once. See L<perlfunc/last>. +=item Can't leave "when" outside a loop + +(F) Control reached the end of a C<when> block that isn't inside any +loop (including a C<given> block). An implicit C<next> occurs here, +which requires a loop to jump to. You probably wanted the C<when> to be +inside a C<given> block. Note that you won't get this error if the match +controlling the C<when> fails, or if you use an explicit C<continue> to +avoid reaching the end of the block. But if you rely on not reaching the +implicit C<next> then you probably didn't want C<when>, but rather C<if>. + =item Can't linearize anonymous symbol table (F) Perl tried to calculate the method resolution order (MRO) of a @@ -1536,13 +1546,6 @@ references can be unweakened. (F) You attempted to weaken something that was not a reference. Only references can be weakened. -=item Can't "when" outside a topicalizer - -(F) You have used a C<when> block that is neither inside a C<foreach> -loop nor a C<given> block. (Note that this error is issued on exit -from the C<when> block, so you won't get the error if the match fails, -or if you use an explicit C<continue>.) - =item Can't x= to read-only value (F) You tried to repeat a constant value (often the undefined value) diff --git a/pod/perlfunc.pod b/pod/perlfunc.pod index d55bf2e6a7..c7375aa1f8 100644 --- a/pod/perlfunc.pod +++ b/pod/perlfunc.pod @@ -1318,9 +1318,8 @@ using an empty one, logically enough, so L<C<next>|/next LABEL> goes directly back to check the condition at the top of the loop. When there is no BLOCK, L<C<continue>|/continue BLOCK> is a function -that exits the current C<when> block, avoiding the jump -to the end of the enclosing topicalizer that implicitly happens when -execution reaches the end of such a block. +that exits the current C<when> block, avoiding the implicit C<next> +that happens when execution reaches the end of such a block. In Perl 5.14 and earlier, this form of L<C<continue>|/continue BLOCK> was only available when the L<C<"switch"> feature|feature/The 'switch' feature> was enabled. See diff --git a/pod/perlsyn.pod b/pod/perlsyn.pod index 9febd729a4..06338303db 100644 --- a/pod/perlsyn.pod +++ b/pod/perlsyn.pod @@ -218,7 +218,7 @@ declaration, or a declaration that implies it. It behaves like the full C<when> statement with block, described in L</"Switch Statements"> below. It executes the statement only if the I<EXPR> is true. If the statement executes, control then implicitly jumps to the end of the dynamically -enclosing C<foreach> or C<given> block. +enclosing loop (usually a C<given> block). =head2 Compound Statements X<statement, compound> X<block> X<bracket, curly> X<curly bracket> X<brace> @@ -589,8 +589,8 @@ The BLOCK construct can be used to emulate case structures. $nothing = 1; } -You'll also find that C<foreach> loop used to create a topicalizer -and a switch: +You'll also find the C<foreach> loop used to establish a topic for +a switch: SWITCH: for ($var) { @@ -642,17 +642,12 @@ exactly one item to iterate over. A C<given> construct even counts as a one-iteration loop for the purposes of loop control, so the C<redo> operator can be used to restart its block, and C<next> or C<last> can be used to exit the block early. -Either a C<given> or a C<foreach> -construct serves as a I<topicalizer>: C<when> can only -be used in the dynamic scope of a topicalizer. C<when> evaluates its argument as a truth value. If the argument was false then it does not execute its block, and proceeds to the following statement. If the argument was true, it executes the block, -then implicitly jumps to the end of the closest dynamically enclosing -topicalizer. (In the case of a C<foreach> topicalizer, this jump -behaves as a C<next>, moving on to the next iteration, not a C<last>, -which would exit the loop.) +then implicitly performs a C<next>, jumping to the end of the closest +dynamically enclosing C<given> block or other kind of loop. Putting this together, the code in the previous section could be rewritten as @@ -678,8 +673,8 @@ less punctuation as You can use the C<continue> keyword to exit a C<when> block, proceeding to the following statement. This is most commonly -done last thing inside the block, to override the implicit jump to the -end of the topicalizer. For example +done last thing inside the block, to override the implicit C<next>. +For example given($foo) { when (/x/) { say '$foo contains an x'; continue } @@ -1482,36 +1482,6 @@ S_dopoptoloop(pTHX_ I32 startingblock) return i; } -/* find the next GIVEN or FOR (with implicit $_) loop context block */ - -STATIC I32 -S_dopoptogivenfor(pTHX_ I32 startingblock) -{ - I32 i; - for (i = startingblock; i >= 0; i--) { - const PERL_CONTEXT *cx = &cxstack[i]; - switch (CxTYPE(cx)) { - default: - continue; - case CXt_LOOP_GIVEN: - DEBUG_l( Perl_deb(aTHX_ "(dopoptogivenfor(): found given at cx=%ld)\n", (long)i)); - return i; - case CXt_LOOP_PLAIN: - assert(!(cx->cx_type & CXp_FOR_DEF)); - break; - case CXt_LOOP_LAZYIV: - case CXt_LOOP_LAZYSV: - case CXt_LOOP_LIST: - case CXt_LOOP_ARY: - if (cx->cx_type & CXp_FOR_DEF) { - DEBUG_l( Perl_deb(aTHX_ "(dopoptogivenfor(): found foreach at cx=%ld)\n", (long)i)); - return i; - } - } - } - return i; -} - STATIC I32 S_dopoptowhen(pTHX_ I32 startingblock) { @@ -4683,9 +4653,9 @@ PP(pp_leavewhen) assert(CxTYPE(cx) == CXt_WHEN); gimme = cx->blk_gimme; - cxix = dopoptogivenfor(cxstack_ix); + cxix = dopoptoloop(cxstack_ix); if (cxix < 0) - DIE(aTHX_ "Can't \"when\" outside a topicalizer"); + DIE(aTHX_ "Can't leave \"when\" outside a loop"); oldsp = PL_stack_base + cx->blk_oldsp; if (gimme == G_VOID) @@ -4693,18 +4663,19 @@ PP(pp_leavewhen) else leave_adjust_stacks(oldsp, oldsp, gimme, 1); - /* pop the WHEN, BLOCK and anything else before the GIVEN/FOR */ + /* pop the WHEN, BLOCK and anything else before the loop */ assert(cxix < cxstack_ix); dounwind(cxix); cx = &cxstack[cxix]; - if (CxFOREACH(cx)) { + if (CxTYPE(cx) != CXt_LOOP_GIVEN) { /* emulate pp_next. Note that any stack(s) cleanup will be * done by the pp_unstack which op_nextop should point to */ cx = CX_CUR(); cx_topblock(cx); PL_curcop = cx->blk_oldcop; + PERL_ASYNC_CHECK(); return cx->blk_loop.my_op->op_nextop; } else { @@ -4898,9 +4898,6 @@ STATIC MAGIC * S_doparseform(pTHX_ SV *sv); STATIC I32 S_dopoptoeval(pTHX_ I32 startingblock) __attribute__warn_unused_result__; -STATIC I32 S_dopoptogivenfor(pTHX_ I32 startingblock) - __attribute__warn_unused_result__; - STATIC I32 S_dopoptolabel(pTHX_ const char *label, STRLEN len, U32 flags) __attribute__warn_unused_result__; #define PERL_ARGS_ASSERT_DOPOPTOLABEL \ diff --git a/t/lib/croak/pp_ctl b/t/lib/croak/pp_ctl index fb81c0a931..09332551ef 100644 --- a/t/lib/croak/pp_ctl +++ b/t/lib/croak/pp_ctl @@ -10,4 +10,4 @@ Can't find label foo at - line 3. use 5.01; no warnings 'experimental::smartmatch'; when(!defined){} EXPECT -Can't "when" outside a topicalizer at - line 2. +Can't leave "when" outside a loop at - line 2. diff --git a/t/op/when.t b/t/op/when.t index 62f0bcd14d..2721b7623d 100644 --- a/t/op/when.t +++ b/t/op/when.t @@ -10,7 +10,7 @@ use strict; use warnings; no warnings 'experimental::smartmatch'; -plan tests => 39; +plan tests => 42; foreach(3) { CORE::when(3) { @@ -177,4 +177,31 @@ foreach(3) { pass; } +foreach my $z (3) { + when(1) { pass; } + fail; +} + +my @a = qw(x y z); +my $act = ""; +while(@a) { + $act .= "[a@{[0+@a]}]"; + when(shift(@a) eq "y") { + $act .= "[b]"; + } + $act .= "[c]"; +} +is $act, "[a3][c][a2][b][a1][c]"; + +$act = ""; +{ + $act .= "[a]"; + when(0) { $act .= "[b]"; } + $act .= "[c]"; + when(1) { $act .= "[d]"; } + $act .= "[e]"; + when(1) { $act .= "[f]"; } +} +is $act, "[a][c][d]"; + 1; |