#1065: PGE should emit inline PIR with Grammar namespace
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Reporter: Austin_Hastings | Owner: pmichaud
Type: bug | Status: new
Priority: normal | Milestone:
Component: PGE | Version: 1.6.0
Severity: low | Keywords: PGE,inline,PIR,actions
Lang: | Patch:
Platform: |
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This code, or at least the first alternate path, is pretty common in PGE
grammars. In my situation, the <ws> token is compiled and becomes part of
the [ 'close' ; 'Grammar' ] namespace.
{{{
token ws {
| <?{{ ## Remember end of last ws, in case rule is called 2x
$P0 = get_global '$!ws'
if null $P0 goto noshort
$P1 = $P0.'to'()
$P2 = match.'to'()
if $P1 != $P2 goto noshort
.return(1)
noshort:
set_global '$!ws', match
.return(0)
}}>
| <!ww> <.WS_ALL>+
| <.WS_ALL>*
}
}}}
When the grammar is compiled, it produces output like this.
{{{
R2267: # closure
$S1 = ".sub anon :anon\n.param pmc match\n\t## Remember end of
last ws, in case rule is called 2x\n\t\t$P0 = get_global '$!ws'\n\t\tif
null $P0 goto noshort\n\t\t$P1 = $P0.'to'()\n\t\t$P2 =
match.'to'()\n\t\tif $P1 != $P2 goto
noshort\n\t\t.return(1)\n\tnoshort:\n\t\tset_global '$!ws',
match\n\t\t.return(0)\n\t\n.end\n"
$P0 = get_hll_global ['PGE';'Match'], '%!cache'
$P1 = $P0[$S1]
unless null $P1 goto R2267_1
$P1 = compreg "PIR"
$P1 = $P1($S1)
$P0[$S1] = $P1
R2267_1:
}}}
The problem is that the anonymous sub that is eval'ed at runtime receives
no namespace. As a result, any calls or variable references must be made
with an explicit namespace resolution -- get_*_global or set_*_global, and
any created symbols wind up in the root namespace by default.
This is wrong because it pollutes the root namespace, and because it puts
the in-line code in a completely different context from all the rest of
the code associated with the grammar.
Inline PIR should be emitted with either the same namespace as the
Grammar, or with the same namespace as the Actions. Given that the actions
are pluggable, and that grammars may be subclassed or re-used, the
simplest answer is probably to use the Grammar namespace.
--
Ticket URL: <https://trac.parrot.org/parrot/ticket/1065>
Parrot <https://trac.parrot.org/parrot/>
Parrot Development
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