G@d&8dZdZdZedfdZdZdZdZdZd S) z LL(1) predictive parser for snippets CFG grammar. Aho, Sethi, Ullman Compilers: Principles, Techniques, and Tools, Addison-Wesley, 1986 a( START -> EXPRLIST EXPRLIST -> EXPR MOREEXPR MOREEXPR -> EXPR MOREEXPR | EPSILON EXPR -> SNIPPET | ANY TEXT_SNIPPETS -> MOREEXPR TEXT -> ANY MOREANY MOREANY -> ANY MOREANY | EPSILON TEXT_NO_COL -> ANY_NO_COL MORE_ANY_NO_COL MORE_ANY_NO_COL -> ANY_NO_COL MORE_ANY_NO_COL | EPSILON TEXT_COL -> ANY_COL MORE_COL MORE_COL -> ANY_COL MORE_COL | EPSILON TEXT_REGEX -> ANY_REGEX MORE_REGEX MORE_REGEX -> ANY_REGEX MORE_REGEX | EPSILON TEXT_FORMAT -> ANY FOLLOW_ANY FOLLOW_ANY -> ANY FOLLOW_ANY | EPSILON ANY_REGEX -> ANY | dollar ANY -> ANY_COL | , ANY_COL -> ANY_NO_COL | COLONS ANY_NO_COL -> name | int | case | SYMBOLS | whitespace | left_curly_name COLONS -> : | :+ | :- | :? SYMBOLS -> \: | \$ | text_pipe | { | \} | \ | \/ | \, | symbol SNIPPET -> dollar SNIPPETBODY SNIPPETBODY -> SNIPPETID | INTSNIPPET | VARSNIPPET INTSNIPPET -> int | { int INTSNIPPETBODY } INTSNIPPETBODY -> COLONBODY | PIPEBODY | EPSILON COLONBODY -> : TEXT_SNIPPETS PIPEBODY -> pipe TEXTSEQ pipe TEXTSEQ -> TEXT_COL MORETEXT MORETEXT -> , TEXT_COL MORETEXT | EPSILON VARSNIPPET -> left_curly_name VARSNIPPETBODY } | name VARSNIPPETBODY -> COLONBODY | REGEXBODY | EPSILON REGEXBODY -> / REGEX / FORMATTEXT / OPTIONS REGEX -> TEXT_REGEX | EPSILON OPTIONS -> TEXT_REGEX | EPSILON FORMATTEXT -> FORMAT MOREFORMAT MOREFORMAT -> FORMAT MOREFORMAT | EPSILON FORMAT -> FORMATEXPR | TEXT_FORMAT FORMATTEXT_NO_COL -> FORMAT_NO_COL MOREFORMAT_NO_COL MOREFORMAT_NO_COL -> FORMAT_NO_COL MOREFORMAT_NO_COL | EPSILON FORMAT_NO_COL -> FORMATEXPR | TEXT_NO_COL FORMATEXPR -> dollar FORMATBODY FORMATBODY -> int | { int FORMATOPTIONS } FORMATOPTIONS -> CASEOPTS | IFOPTS | IFELSEOPTS | ELSEOPTS | EPSILON CASEOPTS -> : FORMATTEXT IFOPTS -> :+ FORMATTEXT IFELSEOPTS -> :? FORMATTEXT_NO_COL : FORMATTEXT ELSEOPTS -> PROLOGFUNCT FORMATTEXT PROLOGFUNCT -> : | :- c`|}d|D}i}|D]v}|d\}}|d}g}|D]=}|}||>|||<w|S)NcBg|]}|dk|S))strip).0lines z'_preprocess_grammar..Ys%JJJdtrzzTZZ\\zzzz -> z | )r splitlinessplitappend)grammar grammar_linesrproduction_namerules productionsrule rule_partss r_preprocess_grammarrWsMMOO..00MJJmJJJMG//!%F!3!3 E""  + +D++--J   z * * * *#.  Nr STARTc^t|}t|}i}|D]1}ttd||D||<2t |||}i}|D]>}i||<||D].\}}} |dkr | |||<||D] } g||| </?||||fS)z/Create LL(1) parsing table for a given grammar.cg|] }|d S))ris rr z,create_LL1_parsing_table..ls888!888r EPSILON)rfirst_no_epsilonlistsetfollow) r starting_rulefnefirstr follow_rules parse_table_sym production follow_syms rcreate_LL1_parsing_tabler*fs!'**G 7 # #C E;;388c$i88899::d '5-88LK77 D"%d) 7 7 AsJi)3 D!#&&".t"477J46K%j117  7 C{ 22r c6i}|D]}t|||}|S)z)Compute FIRST sets for all grammar rules.)r#)rr"rs rrrzs. C((GT3'' Jr cdg}||vr||D]}d}|D]z}||vr||||fd}nY|d}t|||}d}||D]*\} } } | dkr||| |f%|dz }+|dkrd}n{|r||d|f|||<|S)a Compute FIRST set for a given rule. The first set of a sequence of symbols u, written as First(u) is the set of terminals which start the sequences of symbols derivable from u. A bit more formally, consider all strings derivable from u. If u =>* v, where v begins with some terminal, that terminal is in First(u). If u =>* epsilon, then epsilon is in First(u). TFrr)r r#) rrr" first_setr epsilon_foundr(first_production num_epsilonr&r's rr#r#s,I 3"4= A AK M)   W,,$$dJ %DEEE$)ME(31~$S99C"#K%()9%:-- 3)++%,,dC-EFFFF'1,KK"a''(- ( A  $ ;!?@@@D Jr c i}i}dg||<|D]c}g}|D]W}||kr t||D]8\}} t| D]#\} } | |kr|||| f$9X|||<d|D]} t||| |||}|S)z*Compute FOLLOW sets for all grammar rules.z) enumerater _follow) rr"r!r positionrule1rule1_positionrule2rrjr(rs rr r s FH$IF= ) ) = =E~~"+GEN";"; = =;%.{%;%;==MAz!U**&--uam<<<= =)NN#tVX}MM Mr c g}||vs||kr||kr||}||D]\}}} |||} | t| dz krf| | dz} | |vrAd|| D} || z }d|| vrt||||||}|||z }z|| t||||||}|||z }tt |||<|S)aD Compute FOLLOW set for a grammar rule. The follow set of a nonterminal A is the set of terminal symbols that can appear immediately to the right of A in a valid sentence. A bit more formally, for every valid sentence S =>* uAv, where v begins with some terminal, and that terminal is in Follow(A). rcg|] }|dk| S)rr)rxs rr z_follow..s(':':':Q*+y..()*8..r r)lenr4r rr) rr"rr r5r! rule_follow derived_rulerr9r( next_rulenext_rule_firsts rr4r4sVK 6T]22 =  ,K"*4. 4 4 L!Q .q1J3z??Q&&&&q1u- ''':':#i.':':':O?2K C N22!(#|)/="J"J#vl';; &&y1111 #|!'=BBvl33 C ,,--t Mr N)__doc__GRAMMARrr*rr#r r4rr rrDsC L   &-G3333($$$N*!!!!!r