<i>Bug fixes on PT/PEG transformation operations</i> status still Open with 4 other changes
by
ssoberni
2018-06-14 14:57:26.
D 2018-06-14T14:57:26.339
J assignee aku
J comment Hi!\r\n\r\nAs\spromised,\sI\sreworked\sa\sseries\sof\sbug\sfixes\son\sPEG\stransformations\s(realizability,\sdropping)\sinto\sa\sfix\sbranch:\s[https://core.tcl.tk/tcllib/timeline?r=pt-container-ssoberni].\r\n\r\nIn\sshort:\r\n\r\n1.\sminimize:\sthe\sdrop\soperations\swere\sin\swrong\sorder.\r\n\r\n2.\srealizability:\skleene\sstar\sand\soptionals\sshould\sbe\sset\srealizable\sby\sdefinition\s(is\sconsistent\swith\sother\sPEG\senvironments,\sincl.\stcllib's\spage).\r\n\r\n3.\sDrop:\s\r\n\r\no\swrong\svariable\sname\sin\sone,\spreviously\suntested\scode\sbranch.\r\n\r\no\sdrop\swas\stoo\spermissive\son\sexpressions\sother\sthan\schoice.\sIn\sline\swith\sthe\srealizability\sruling,\sonly\schoice\sshould\ssurvive\sany\sremoved\schildren.\r\n\r\nGenerally,\soffering\sthe\sotherwise\sCFG-aware\sgrammar\stransformations\sshould\smaybe\sprominently\sbe\smarked\swith\sa\sdisclaimer\sin\sthe\sdocs?\sThis\sis\sbecause\streating\sa\sPEG\sas\sa\sCFG\sis\snot\snecessarily\sa\sgood\sidea,\salthough\slimited\suse\sof\stransformations\sis\swarranted.\sA\sdisclaimer\sshould\sstate\sthat\srealizability\sof\san\sordered\schoice\scannot\sbe\sdecided\sstatically\sand\sis\sconceptually\sitchy\s(non-disjointness).\sAlso,\srealizability\sof\spredicates\sis\scertainly\sdebatable\s(in\sthe\ssense\sof\sa\snon-productive\sor\sa\snon-recognising\sexpression).\sIn\sany\scase,\sthe\smessage\sshould\sbe\sthat\sthe\sresult\sof\sa\sminimisation\swill\snot\syield\sa\sminimal\sPEG,\srather\sa\sconservative\sapproximation\sof\sa\sminimisation,\sat\sbest.\r\n\r\nWhat\sdo\syou\sthink?\r\n\r\nFinal\sobservation,\sbut\salso\sdebatable:\s::pt::peg::op::drop::unrealizable\sstarts\sfrom\sthe\sset\sof\sdefined\snon-terminals\s(RHS\sof\srules),\sand\snot\sall\sreachable\sones.\sThis\sis\snot\san\sissue\sper\sse,\sbut\sif\sone\scomposes\sPEGs\sor\sthe\scorresponding\srules\s(e.g.,\swith\sdeferred\snon-terminals)\sthen\sthey\swill\sbe\sjust\sdropped,\salong\swith\smost\sof\sthe\srest\sof\sthe\srules\sset.\sA\smore\spermissive,\sconservative\ssetting\swould\sswitching\sfrom\r\n\r\n\s\s\sset\sall\s[$container\snonterminals]\r\n\r\nto\r\n\r\n\s\s\sset\sall\s[::pt::peg::op\sreachable\s$container]\r\n\r\nLet\sme\sknow\swhat\syou\sthink!\r\n\r\nThx,\r\nStefan
J login ssoberni
J mimetype text/plain
K 351b8b2f55519f12d5c4f889b68ecee7db97118a
U ssoberni
Z 753789fbcb6b976b72e545ef0ca0ff1d
