LRパーサーはいいぞ

Kernel/VM探検隊@関西 11回目「LRパーサーはいいぞ」の発表スライド
https://kernelvm.connpass.com/event/347564/

Transcript

1. -3
   QBSTFS͸͍͍ͧ 4VOEBZ
   .BZ
   
   
   ,FSOFM7.୳ݕୂ!ؔ੢
   ճ໨
   !ZEBI
   :VEBJ
   5BLBEB
2. XIPBNJ ߴా
   ༤େ
   
   :VEBJ
   5BLBEB
   (JU)VC
   ZEBI
   5XJUUFS
   ZEBI@
   4PGUXBSF
   FOHJOFFS
   $3VCZ
   DPNNJUUFS
   NBJOMZ
   EFWFMPQ
   QBSTFS
   SFMBUFE
   GFBUVSFT
   "
   DPNNJUUFS
   PG
   SVCZMSBNB
   -"-3
   QBSTFS
   HFOFSBUPS
   $IJFG
   PSHBOJ[FS
   PG
   ,BOTBJ3VCZ,BJHJ
   
   !ઌేொՎ෣࿅৔
3. 3VCZ,BJHJ
   
   QIPUP IUUQTYDPN-JUUMF@3VCZJTUTUBUVT .F
4. 3VCZͰ͸ࠓ1BSTFS͕೤͍ 3VCZ,BJHJͰ͸͜͜೥ؒͰηογϣϯ
   ࠓ೥΋ηογϣϯ
   3VCZʹ͸ࠓೋͭͷ1BSTFS͕ଘࡏ͍ͯ͠Δ
   ϑϧεΫϥονͰ࣮૷͢Δखॻ͖1BSTFS
   ύʔαʔδΣωϨʔλʹΑͬͯੜ੒͞ΕΔ1BSTFS
   ࠓ೔͸ͬͪ͜ͷ࿩
5. 1BSTFSͱ͸ จ๏نଇʹैͬͯهड़͞ΕͨςΩετΛղੳ͠ɺϓϩάϥϜͰѻ͑ΔΑ͏ ͳσʔλߏ଄ʹม׵͢ΔϓϩάϥϜ΍ɺͦͷॲཧΛࢦ͢
   1BSTFSͷ͓࢓ࣄ
   ೖྗ͞ΕͨςΩετ΍σʔλͷಡऔʢࣈ۟ղੳʣ
   จ๏نଇʹैͬͯղੳ
   ߏ଄Խ͞Εͨσʔλʢଟ͘ͷ৔߹ɺߏจ໦΍τʔΫϯྻʣʹม׵
6. 1BSTFSͱ-FYFS ࣈ
   ۟
   ղ
   ੳ
   ث ߏ
   จ
   ղ
   ੳ
   ث จࣈྻ όΠτྻ τʔΫϯྻ ந৅ߏจ໦ "45
7. 1BSTFSͱ-FYFS ࣈ
   ۟
   ղ
   ੳ
   ث ߏ
   จ
   ղ
   ੳ
   ث จࣈྻ όΠτྻ τʔΫϯྻ ந৅ߏจ໦ "45
8. -FYFS def method_name(param) puts param end ೖྗ͸ίʔυͷจࣈྻ
9. -FYFS ॲཧܥ͔ΒݟΔͱόΠτྻ
   จࣈͷฒͼΛղੳ͠ɺҙຯͷ͋Δ࠷খͷ୯ҐʢτʔΫϯʣʹ෼ղ͢Δ 64 65 66 20 6d 65 74 68 6f 64 5f 6e 61 6d 65 28 70 61 72 61 6d 29 0a 20 20 70 75 74 73 20 70 61 72 61 6d 0a 65 6e 64 def method_name param
10. 1BSTFSͱ-FYFS ࣈ
    ۟
    ղ
    ੳ
    ث ߏ
    จ
    ղ
    ੳ
    ث จࣈྻ όΠτྻ τʔΫϯྻ ந৅ߏจ໦ "45
11. 1BSTFS τʔΫϯྻ͕จ๏తʹਖ਼͍͔͠Λݕࠪͯ͠ந৅ߏจ໦ "45 Λ࡞੒͢Δ def method_name(param) puts param end defn ar g s body fcall puts ar g s '(' keyword_def tIDENTIFIER tIDENTIFIER ')' ...
12. 1BSTFS
    HFOFSBUPS 構 文 解 析 器 生 成 器 จ๏ϑΝΠϧ 1BSTFS
13. 1BSTFS
    HFOFSBUPS 構 文 解 析 器 生 成 器 จ๏ϑΝΠϧ 1BSTFS
14. จ๏ϑΝΠϧ #/' #BDLVTr/BVS
    'PSN Ͱจ๏Λهड़͢Δ
    #/'ͱ͸จ๏نଇΛఆٛ͢ΔͨΊͷه๏Ͱɺਓؒʹͱͬͯ௚ײతͰཧղ͠΍͍͢ expr : NUMBER { $$ = $1; } | expr '+' expr { $$ = $1 + $3; } ;
15. 1BSTFS
    HFOFSBUPS 構 文 解 析 器 生 成 器 จ๏ϑΝΠϧ 1BSTFS
16. 1BSTFS
    HFOFSBUPS ͦͷ໊ͷ௨Γ1BSTFSΛੜ੒͢ΔͨΊͷπʔϧ
    ղੳ͍ͨ͠ݴޠͷจ๏ఆٛΛೖྗͱͯ͠ड͚औͬͯɺͦͷจ๏ʹैͬͯߏ จղੳΛߦ͏ͨΊͷ1BSTFSͷίʔυΛॻ͖ग़͢
    3VCZͰ͸௕Β͘(/6
    #JTPOΛ࢖͖͍ͬͯͯͨ
    3VCZ
    
    ೥݄ ͔Β͸-SBNBͱ͍͏3VCZ੡ͷ1BSTFS
    HFOFSBUPSʹஔ͖׵Θͬͨ
17. ͳͥ#JTPOΛஔ͖׵͑ͨʁ
18. #JTPOΛஔ͖׵͑ͨཧ༝ #JTPOͷWFSTJPO͸؀ڥʹΑͬͯҟͳΔͷͰෳ਺WFSTJPOͷαϙʔτ͕ඞཁ
    ιʔείʔυ͔ΒϏϧυ͢Δ৔߹͸ɺͦͷ؀ڥͰΠϯετʔϧ͞Ε͍ͯΔ #JTPO͕࢖ΘΕΔ
    #JTPOʹ௥Ճ͞Εͨ৽͍͠ػೳ΋͙͢ʹ࢖͏͜ͱ͕Ͱ͖ͳ͍ɹ
    #JTPOʹػೳΛ௥Ճͨ͠ΓػೳΛ֦ு͢Δͷ͸೉͍͠
    #JTPOͷϢʔβʔ͸໪࿦3VCZ͚ͩͰ͸ͳ͍ʢͦΕ͸ͦ͏ʣ
    มߋ͢Δʹ͸ଟ͘ͷௐ੔΍ٞ࿦͕ඞཁ
19. SVCZMSBNB
    1VSF
    3VCZ
    -"-3
    QBSTFS
    HFOFSBUPS 3VCZ੡ͷ-"-3  ύʔαδΣωϨʔλ
    3VCZίϛολͷ:VJDIJSP
    ,BOFLP !ZVJLOL ͞Μ͕࡞ऀ
    #JTPOܗࣜͷจ๏ϑΝΠϧΛೖྗͱͯ͠$Ͱॻ͔Εͨ1BSTFSΛग़ྗ͢Δ
    3VCZ͕࢖༻͍ͯ͠Δจ๏ʹݶͬͯ͸#JTPOͱޓ׵ੑ͕͋Δ
    :BDDɺ#JTPOͱ͍͏ϞϑϞϑͷ࢛଍าߦͷಈ෺ͷܥේͰͷ໋໊
    -MBNBͩͱ--ύʔαʔʹݟ͑ΔͷͰ
    -3BNB
    ͱ͍͏௲Γʹ
20. 1BSTFS
    (FOFSBUPS ΞʔΩςΫνϟ $PNNBOE
    -JOF
    *OUFSGBDF จ๏ϑΝΠϧ 1BSTFS (SBNNBS
    4ZTUFN 4UBUF
    .BOBHFS $PEF
    (FOFSBUPS
21. 1BSTFS
    (FOFSBUPS ΞʔΩςΫνϟ $PNNBOE
    -JOF
    *OUFSGBDF จ๏ϑΝΠϧ 1BSTFS (SBNNBS
    4ZTUFN 4UBUF
    .BOBHFS $PEF
    (FOFSBUPS
22. $PNNBOE
    -JOF
    *OUFSGBDF -SBNBͷίϚϯυ࣮ߦΛ࢘Δத৺తͳΫϥε
    ೖྗͱͳΔจ๏ϑΝΠϧ΍֤छΦϓγϣϯΛड͚औͬͯɺ1BSTFSੜ੒ϓϩ ηεશମͷΦʔέετϨʔγϣϯΛߦ͏ % lrama - h Lrama is LALR (1) parser generator written by Ruby. Usage: lrama [options] FILE STDIN mode: lrama [options] - FILE read grammar from STDIN Tuning the Parser: -S, - - skeleton=FILE specify the skeleton to use - t, - - debug display debugging outputs of internal parser same as '-Dparse.trace' - - locations enable location support -D, - - def i ne=NAME[=VALUE] similar to '%def i ne NAME VALUE'
23. 1BSTFS
    (FOFSBUPS ΞʔΩςΫνϟ $PNNBOE
    -JOF
    *OUFSGBDF จ๏ϑΝΠϧ 1BSTFS (SBNNBS
    4ZTUFN 4UBUF
    .BOBHFS $PEF
    (FOFSBUPS
24. (SBNNBS
    4ZTUFN ೖྗ͞Εͨจ๏ϑΝΠϧΛղੳ͢Δ੹೚Λ࣋ͭ
    ҎԼΛऔΓࠐΈɺίʔυੜ੒ʹར༻Մೳͳ಺෦తͳจ๏දݱΛߏங
    จ๏نଇɺऴ୺ه߸ɾඇऴ୺ه߸ͱ͍ͬͨγϯϘϧ
    ԋࢉࢠͷ༏ઌॱҐએݴ
    ϢʔβʔఆٛͷΞΫγϣϯίʔυ
25. (SBNNBS
    4ZTUFN -FYFSͱ1BSTFSΛ͍࣋ͬͯΔ
    -FYFS
    ਖ਼نදݱͰτʔΫϯΛ੾Γग़͍ͯ͠Δ
    1BSTFS
    SVCZSBDD
    ͱ͍͏1BSTFS
    (FOFSBUPSΛ࢖ͬͯੜ੒͍ͯ͠Δ
    SBDD
    ੨໦ๆ࿠͞Μ͕࡞ऀͷ-"-3 
    1BSTFS
    (FOFSBUPS
    3VCZͰॻ͔Εͨ1BSTFSΛग़ྗ͢Δ
26. SBDDͰ#JTPOΛஔ͖׵͑Ε͹͍͍ͷͰ͸ ੜ੒ΞϧΰϦζϜ͸ಉ͡Ͱ-"-3 
    ೖྗͷจ๏ϑΝΠϧͦͷ΋ͷͷจ๏ϑΝΠϧ͕ҟͳΔ
    #JTPO͸:BDD#JTPOܗࣜɺSBDD͸ಠࣗͷه๏
    ग़ྗ͢Δ1BSTFSͷݴޠ͕ҟͳΔ
    #JTJPO͸$ݴޠɺSBDD͸3VCZ parser_option: "%expect" INTEGER { @grammar.expect = val[1] } | "%def i ne" variable value { @grammar.def i ne[val[1].s_value] = val[2]&.s_value }
27. (SBNNBS
    4ZTUFN "DUJPOTͷ෦෼ͷղੳ΍ࢀরղܾ΋ඞཁ
    "DUJPO͸จ๏نଇʹҰகͯؐ͠ݩ͢Δॠؒʹ࣮ߦ͞ΕΔ
    ΍ɺOɺ!Oͱ͍͏ಛघͳม਺Λ࢖༻͢Δ͜ͱͰऴ୺ɾඇऴ୺ه߸ͷ஋ ΍Ґஔ৘ใʹΞΫηεՄೳͳͷͰɺͦΕΒΛஔ͖׵͑Δ if_tail: opt_else | k_elsif expr_value then compstmt(stmts) if_tail { $$ = new_if(p, $2, $4, $5, &@$, &@1, &@3, &NULL_LOC); f i xpos($$, $2); / * % ripper: elsif!($ : 2, $ : 4, $ : 5) % * / } ;
28. 1BSTFS
    (FOFSBUPS ΞʔΩςΫνϟ $PNNBOE
    -JOF
    *OUFSGBDF จ๏ϑΝΠϧ 1BSTFS (SBNNBS
    4ZTUFN 4UBUF
    .BOBHFS $PEF
    (FOFSBUPS
29. 4UBUF
    .BOBHFS (SBNNBS
    4ZTUFN͔Βड͚औͬͨ಺෦จ๏දݱΛ༻͍ͯɺεςʔτϚγ ϯΛܭࢉ͓Αͼ؅ཧ͠·͢
    ·ͨɺߏจղੳදΛੜ੒͢Δ໾ׂ΋୲͍ͬͯΔ
30. 1BSTFS
    (FOFSBUPS ΞʔΩςΫνϟ $PNNBOE
    -JOF
    *OUFSGBDF จ๏ϑΝΠϧ 1BSTFS (SBNNBS
    4ZTUFN 4UBUF
    .BOBHFS $PEF
    (FOFSBUPS
31. $PEF
    (FOFSBUPS εςʔτϚγϯͱߏจղੳදΛݩʹ࣮ߦՄೳͳ1BSTFSͷίʔυΛੜ੒͢Δ
    5FNQMBUFʹ஋ΛຒΊࠐΜͰ͍͘
    SVCZFSC
    ͱ͍͏ςϯϓϨʔτγεςϜΛ࢖ͬͯຒΊࠐΉ / * - - - - - - - - - - . | yyparse. | ` - - - - - - - - - - * / int yyparse (<%= output.parse_param %>) { <%# b4_declare_scanner_communication_variables -%> / * Lookahead token kind. * / int yychar; / * The semantic value of the lookahead symbol. * / / * Default value used for initialization, for pacifying older GCCs or non-GCC compilers. * / #ifdef _ _ cplusplus static const YYSTYPE yyval_default = {}; (void) yyval_default; #else YY_INITIAL_VALUE (static const YYSTYPE yyval_default;)
32. ػೳͷ֦ு
33. ͱ͸͍͑1BSTFS
    HFOFSBUPSͷྺ࢙͸ݹ͍ ೥ʹ5POZ
    #SPPLFSͱ%FSSJDL
    .PSSJTʹΑͬͯઃܭ͕։࢝͞Εͨ#SPPLFS
    .PSSJT
    $PNQJMFS
    $PNQJMFS͕࠷ݹʢͳ͸ͣʣ
    ೥୅ॳ಄ʹ͸4UFQIFO
    $
    +PIOTPO͕:BDDΛ։ൃ
    ೥ʹ3PCFSU
    $PSCFUUʹΑͬͯ(/6
    #JTPO͕ॻ͔Εͨ
    ೥୅Ҏ߱͸ԼՐʹ
    ($$͸౰ॳ#JTPOΛ࢖͍͕ͬͯͨखॻ͖ͷ࠶ؼԼ߱1BSTFSʹ
    (P΋ಉ༷ʹ೥ʹखॻ͖ͷεΩϟφͱ1BSTFSʹ
34. ػೳΛ֦ுͷ༨஍ͬͯ͋Δͷʁ ͦ΋ͦ΋#JTPOͬͯ೥͔Β։ൃ͕ଓ͍͍ͯΔΜͰ͠ΐʁͦΜͳ֦ு͢ Δ༨஍͸͋Δͷʁ
    ൺֱతɺ#JTPO͕αϙʔτ͍ͯ͠Δจ๏͸ϓϦϛςΟϒ
    ྫ͑͹ɺଞͷ1BSTFS
    HFOFSBUPSͷػೳ΍αϙʔτ͍ͯ͠Δศརͳจ๏ Λ࣮૷͢Ε͹#FUUFS
    #JTPO͕Ͱ͖Δ͔΋͠Εͳ͍
35. จ๏ͷ֦ு
36. ΋ͬͱ͍͍ײ͡ͷจ๏͕΄͍͠ #JTPO͕ఏڙ͍ͯ͠Δจ๏͸ϓϦϛςΟϒʢ࠶ܝʣ
    ৑௕Ͱந৅Խͷ༨஍͕͋ΔίʔυΛΈͨΒؔ਺ʹ੾Γग़͍ͨ͠
    ͕͔ͩ͠͠ɺͦΜͳจ๏͸ͳ͍
37. 1BSBNFUFSJ[JOH
    3VMFT 0$BNM޲͚ͷ-3 
    QBSTFS
    HFOFSBUPSͰ͋Δ.FOIJSͷศརػೳ
    ੜ੒نଇͷඇऴ୺ه߸ͷఆٛʹ͓͚Δڞ௨తͳύλʔϯΛந৅Խ͢ΔͨΊ ͷจ๏Λఏڙ͢Δ
    Πϝʔδͱͯ͠͸ϝιουͱͯ͠நग़Ͱ͖ΔΑ͏ʹ͢ΔͨΊͷػೳ
    .FOIJS
    3FGFSFODF
    .BOVBM
    WFSTJPO
    
    IUUQTHBMMJVNJOSJBGSdGQPUUJFSNFOIJSNBOVBMIUNMTFD
38. ࣅͨΑ͏ͳߏ଄͸Α͋͘Δ stmt : keyword_alias f i tem . . . | lhs '=' lex_ctxt mrhs { $$ = node_assign(p, $1, $4, $3, &@$); / * % ripper: assign!($ : 1, $ : 4) % * / } command_asgn : lhs '=' lex_ctxt command_rhs { $$ = node_assign(p, $1, $4, $3, &@$); / * % ripper: assign!($ : 1, $ : 4) % * / } arg : lhs '=' lex_ctxt arg_rhs { $$ = node_assign(p, $1, $4, $3, &@$); / * % ripper: assign!($ : 1, $ : 4) % * / }
39. ࣅͨΑ͏ͳߏ଄͸Α͋͘Δ stmt : keyword_alias f i tem . . . | lhs '=' lex_ctxt mrhs { $$ = node_assign(p, $1, $4, $3, &@$); / * % ripper: assign!($ : 1, $ : 4) % * / } command_asgn : lhs '=' lex_ctxt command_rhs { $$ = node_assign(p, $1, $4, $3, &@$); / * % ripper: assign!($ : 1, $ : 4) % * / } arg : lhs '=' lex_ctxt arg_rhs { $$ = node_assign(p, $1, $4, $3, &@$); / * % ripper: assign!($ : 1, $ : 4) % * / }
40. ߏ଄Λநग़͢Δ͜ͱ͕Ͱ͖Δ %rule asgn(rhs) <node> : lhs '=' lex_ctxt rhs { $$ = node_assign(p, $1, $4, $3, &@$); / * % ripper: assign!($ : 1, $ : 4) % * / } ; stmt : keyword_alias f i tem . . . | asgn(rhs) ; arg : asgn(arg_rhs) ; command_asgn : asgn(command_rhs) ;
41. ύϥϝʔλͱͯ͠5PLFOΛ౉͢͜ͱ͕Ͱ͖Δ %rule asgn(rhs) <node> : lhs '=' lex_ctxt rhs { $$ = node_assign(p, $1, $4, $3, &@$); / * % ripper: assign!($ : 1, $ : 4) % * / } ; stmt : keyword_alias f i tem . . . | asgn(rhs) ; arg : asgn(arg_rhs) ; command_asgn : asgn(command_rhs) ;
42. ౉͞Εͨ5PLFOΛӈลʹల։͢Δ %rule asgn(rhs) <node> : lhs '=' lex_ctxt rhs { $$ = node_assign(p, $1, $4, $3, &@$); / * % ripper: assign!($ : 1, $ : 4) % * / } ; stmt : keyword_alias f i tem . . . | asgn(rhs) ; arg : asgn(arg_rhs) ; command_asgn : asgn(command_rhs) ;
43. ౉͞Εͨ5PLFOΛӈลʹల։͢Δ %rule asgn(rhs) <node> : lhs '=' lex_ctxt rhsarg_rhs { $$ = node_assign(p, $1, $4, $3, &@$); / * % ripper: assign!($ : 1, $ : 4) % * / } ; stmt : keyword_alias f i tem . . . | asgn(rhs) ; arg : asgn(arg_rhs) ; command_asgn : asgn(command_rhs) ;
44. ౉͞Εͨ5PLFOΛӈลʹల։͢Δ %rule asgn(rhs) <node> : lhs '=' lex_ctxt rhscommand_rhs { $$ = node_assign(p, $1, $4, $3, &@$); / * % ripper: assign!($ : 1, $ : 4) % * / } ; stmt : keyword_alias f i tem . . . | asgn(rhs) ; arg : asgn(arg_rhs) ; command_asgn : asgn(command_rhs) ;
45. ػೳͷ֦ு
46. จ๏ͷߏ଄Λ͍͍ײ͡ʹݟ͍ͨ brace_block : '{' brace_body '}' { $$ = $2; set_embraced_location($$, &@1, &@3); / * % ripper: $ : 2 % * / } | k_do do_body k_end { $$ = $2; set_embraced_location($$, &@1, &@3); / * % ripper: $ : 2 % * / } ;
47. จ๏ͷߏ଄ͱ"DUJPO͕ࠞࡏ brace_block : '{' brace_body '}' { $$ = $2; set_embraced_location($$, &@1, &@3); / * % ripper: $ : 2 % * / } | k_do do_body k_end { $$ = $2; set_embraced_location($$, &@1, &@3); / * % ripper: $ : 2 % * / } ;
48. จ๏ͷߏ଄ͱ"DUJPO͕ࠞࡏ brace_block : '{' brace_body '}' { $$ = $2; set_embraced_location($$, &@1, &@3); / * % ripper: $ : 2 % * / } | k_do do_body k_end { $$ = $2; set_embraced_location($$, &@1, &@3); / * % ripper: $ : 2 % * / } ;
49. 3BJMSPBE
    %JBHSBN +BWB4DSJQU޲͚ͷ1BSTFS
    #VJMEJOHπʔϧΩοτ$IFWSPUBJOͷػೳ
    IUUQTHJUIVCDPN$IFWSPUBJODIFWSPUBJO
    จ຺ࣗ༝จ๏Λߏจਤͱͯ͠දݱ͢ΔͨΊͷػೳͰ#/'Λࢹ֮ԽͰ͖Δ
50. ZEBISBJMSPBE@EJBHSBNT $IFWSPUBJO͕ґଘ͍ͯ͠Δ
    UBCBULJOTSBJMSPBEEJBHSBNT
    ͕αϙʔτ͠ ͍ͯΔͷ͸+BWB4DSJQUͱ1ZUIPO͚ͩͩͬͨͷͰ3VCZ޲͚ʹ࣮૷ͨ͠
    IUUQTHJUIVCDPNZEBISBJMSPBE@EJBHSBNT
    ଍Γ͍ͯͳ͍ػೳ΍ϥΠϒϥϦ͕͋Ε͹3VCZͰ࡞Δ ྗ͸ύϫʔ
    #JTPOͩͱ͜͏͍͏ྗٕͰ৽ػೳΛ૊ΈࠐΉͷ͸೉͍͠
    -SBNBͳΒࣗ෼ͨͪͷ1BSTFS
    (FOFSBUPSͳͷͰ΍Γ΍͍͢
51. ࢥΘ͵෭࢈෺ -SBNB͸#JTPOͱޓ׵͕͋Δ
    #JTPOͰੜ੒͍ͯ͠Δύʔαʔ͸͢΂ͯ7JTVBMJ[FͰ͖Δ
    1)1 ;FOE
    1BSTFS ɺ1FSMɺ.Z42-౳
52. ͔͜͜Βࢼͤ·͢ ZEBIHJUIVCJPSBJMSPBEEJBHSBNDPMMFDUJPO
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