2.\u4fdd\u7559\u5b57\u3001Id<\/p>\n
- \n
- reserved = if|while|do|\u2026<\/li>\n
- letter = [a-z A-z]<\/li>\n
- digit = [0-9]<\/li>\n
- identifier = letter(letter|digit)*<\/li>\n<\/ul>\n
\n\u6839\u636eREX\u6784\u5efaNFA<\/h3>\n
<\/p>\n
<\/p>\n
DFA \u4e0e NFA \u7684\u8f6c\u6362<\/h3>\n
\u4ece NFA \u7684\u5f00\u59cb\u7b26\u53f7S\u5f00\u59cb\uff0c\u6c42\u5b83\u7684\u03b5\u95ed\u5305\uff0c\u7136\u540e\u518d\u770b\u8fd9\u4e2a\u95ed\u5305\u53ef\u4ee5\u5230\u8fbe\u7684\u4f4d\u7f6e\uff0c\u6700\u540e\u628a\u8fd9\u4e9b\u95ed\u5305\u4f5c\u4e3a\u4e00\u4e2a\u72b6\u6001\u3002<\/p>\n
\nEBNF \u6269\u5145\u7684\u5df4\u79d1\u65af\u8303\u5f0f<\/h3>\n
\u5143\u8bed\u8a00\uff1a\u2192\u3001::=\u3001|<\/p>\n
- \n
- \u7528{a}\u8868\u793a\u95ed\u5305\u8fd0\u7b97a*<\/li>\n
- \u7528{a}0n<\/sup>\u8868\u793a\u53ef\u91cd\u590d0\u6b21\u81f3N\u6b21<\/li>\n
- \u7528[a]\u8868\u793a{a}01<\/sup>\uff0c\u5373a|\u03b5<\/li>\n<\/ul>\n
\n\u4e8c\u4e49\u6587\u6cd5\u5b9a\u4e49<\/h3>\n
an ambiguous grammar<\/span>: a grammar that generates a string with two distinct parse trees is called an ambiguous grammar.<\/span><\/p>\n
\u4e00\u79cd\u751f\u6210\u5177\u6709\u4e24\u4e2a\u4e0d\u540c\u89e3\u6790\u6811<\/strong>\u7684\u5b57\u7b26\u4e32\u7684\u8bed\u6cd5\u79f0\u4e3a\u4e8c\u4e49\u8bed\u6cd5\u3002<\/span><\/p>\n
\nLL(1)\u6587\u6cd5\uff1a\u6d88\u9664\u5de6\u9012\u5f52<\/h3>\n
1.\u76f4\u63a5\u5de6\u9012\u5f52<\/p>\n
P -> Pa|b<\/code><\/p>\n\u76f4\u63a5\u5de6\u9012\u5f52\u53d8\u53f3\u9012\u5f52\uff1a<\/p>\n
P -> bP'<\/code><\/p>\nP' -> aP' |\u00a0<\/code>\u03b5<\/code><\/strong><\/p>\n2.\u95f4\u63a5\u5de6\u9012\u5f52<\/p>\n
\u6761\u4ef6\uff1a\u4e0d\u542b\u00a0\u03b5 \u7684\u4ea7\u751f\u5f0f\u3001\u4e0d\u542b\u56de\u8def\u3002<\/p>\n
*\u6309\u67d0\u79cd\u987a\u5e8f\u6392\u5217 P1,P2,…,PN\u3002<\/p>\n
*\u628aPi\u7684\u89c4\u5219\u6539\u6210
Pi->a...|Pi+1...|....<\/code> \uff08Pi\u4e0d\u542bi\u4ee5\u524d\u7684\u9879\uff09<\/p>\n*\u628a\u95f4\u63a5\u5de6\u9012\u5f52\u4e2d\u7684\u5f15\u7528\u66ff\u6362\u4e3a\u5b83\u7684\u5b9a\u4e49\u3002<\/p>\n
*\u5220\u9664\u6c38\u8fdc\u65e0\u6cd5\u5230\u8fbe\u7684\u89c4\u5219\u3002<\/p>\n
<\/p>\n
LL(1)\u6587\u6cd5\uff1a\u6d88\u9664\u56de\u6eaf<\/h3>\n
A -> cb1|cb2|cb3 ...<\/code><\/p>\n*\u63d0\u53d6\u5de6\u516c\u5171\u56e0\u5b50<\/p>\n
A -> cA'<\/code><\/p>\nA' -> b1|b2|b3 ...<\/code><\/p>\n<\/p>\n
First \u96c6\u5408<\/h3>\n
\u4e00\u4e2a\u4e32\u80fd\u63a8\u51fa\u7684\u4efb\u610f\u4e32\uff0c\u6392\u5728\u5f00\u5934\u4f4d\u7f6e\u7684\u7ec8\u7ed3\u7b26<\/strong>\u3002<\/p>\n
*\u5982\u679cx\u80fd\u63a8\u51fa\u03b5\uff0c\u5219\u03b5\u4e5f\u5904\u4e8eFirst(x)\u3002<\/p>\n
<\/p>\n
Follow \u96c6\u5408<\/h3>\n
\u5728\u67d0\u4e2a\u53e5\u578b\u91cc\uff0c\u80fd\u8ddf\u5728\u8fd9\u4e2a\u4e32\u540e\u9762\u7684\u7ec8\u7ed3\u7b26<\/strong>\u3002<\/p>\n
*\u5bf9\u5f00\u59cb\u7b26\u53f7S\uff0c\u628a$\u7f6e\u4e8eFollow(S)\u4e2d\u3002<\/p>\n
*\u82e5A->aBb\uff0c \u5219\u628aFirst(b)\u4e2d\u975e\u03b5\u5143\u7d20\u52a0\u5165Follow(B)\u3002<\/p>\n
*\u82e5A->aB\uff0c\u5219\u628aFollow(A)\u52a0\u81f3Follow(B)\u4e2d\u3002<\/p>\n
<\/p>\n
LL(1)\u6587\u6cd5\u7684\u5224\u5b9a<\/h3>\n
1.\u6587\u6cd5\u4e0d\u542b\u5de6\u9012\u5f52<\/p>\n
2.\u5bf9\u6bcf\u4e00\u4e2a\u975e\u7ec8\u7ed3\u7b26A\u7684\u4ea7\u751f\u5f0f\u5019\u9009\u9996\u7b26\u96c6\u4e24\u4e24\u4e0d\u76f8\u4ea4\u3002<\/p>\n
\u5373 First(ai)\u2229First(aj) = \u2205<\/p><\/blockquote>\n
3.\u5bf9\u6587\u6cd5\u7684\u6bcf\u4e2a\u7ec8\u7ed3\u7b26A\uff0c\u82e5\u5b83\u5b58\u5728\u67d0\u4e2a\u5019\u9009\u9996\u7b26\u96c6\u5305\u542b\u03b5\uff0c\u5219<\/p>\n
First(ai)\u2229Follow(A) = \u2205<\/p><\/blockquote>\n
<\/p>\n
LL(1)\u5206\u6790\u6cd5<\/h3>\n
\n\n
\n Step<\/td>\n Stack<\/td>\n Input<\/td>\n Action<\/td>\n<\/tr>\n \n number<\/td>\n $\u8d77\u59cb\u7b26\u53f7<\/td>\n \u5806\u6808\u5185\u5bb9$<\/td>\n match|<\/p>\n \u4f7f\u7528\u4ea7\u751f\u5f0f\u5339\u914d|<\/p>\n
\u5bf9\u4e8eStack=Input=$\u65f6\u4e3aAccept<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n
<\/p>\n
LL(1)\u5206\u6790\u8868<\/h3>\n
\n\n
\n M[A,b]<\/td>\n \u7ec8\u7ed3\u7b26<\/td>\n<\/tr>\n \n \u975e\u7ec8\u7ed3\u7b26<\/td>\n <\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n <\/p>\n
*A->a \u653e\u5728A\u884cFirst(a)\u5217<\/p>\n
*A->\u03b5 \u653e\u5728A\u884cFollow(A)\u5217<\/p>\n
\n\u6d3b\u524d\u7f00<\/h3>\n
Determining the next handle in a parse is the main task of a shift-reduce parser.<\/p>\n
The sequence of symbols on the parsing stack is called a viable prefix<\/strong> of the right sentential form .<\/p>\n
\nLR(0)\u5206\u6790\u6cd5<\/h3>\n
*\u5728\u4ea7\u751f\u5f0f\u7684\u57fa\u7840\u4e0a\u589e\u52a0\u4e00\u4e9b\u4f4d\u7f6e\u4fe1\u606f<\/strong>\u7ec4\u6210 Item.<\/p>\n
\n\n
\n Step<\/td>\n Parsing stack<\/td>\n Input<\/td>\n Action<\/td>\n<\/tr>\n \n number<\/td>\n $<\/td>\n \u8f93\u5165\u5185\u5bb9 $<\/td>\n Shift|<\/p>\n Reduce|<\/p>\n
\u5bf9\u4e8eParsing stack\u4e3aS\u65f6Accept<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n
<\/p>\n
LR(0)\u5206\u6790\u8868<\/h3>\n
\n\n
\n State<\/td>\n Input<\/td>\n Goto<\/td>\n<\/tr>\n \n number<\/td>\n s+state|<\/p>\n r+\u4ea7\u751f\u5f0f\u7f16\u53f7<\/td>\n
state<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n <\/p>\n
Input\u4e0b\u6709\u591a\u79cd\u7ec8\u7ed3\u7b26\uff0cGo\u4e0b\u6709\u591a\u79cd\u975e\u7ec8\u7ed3\u7b26\u3002Goto\u8868\u793a\u5f53Parsing\u6808\u9876\u4e3a\u975e\u7ec8\u7ed3\u7b26\u65f6\u8df3\u8f6c\u5230\u54ea\u4e2a\u72b6\u6001\u3002<\/p>\n
\nSLR(1)\u6587\u6cd5\u5224\u5b9a<\/h3>\n
1.\u65e0\u79fb\u8fdb\u5f52\u7ea6\u51b2\u7a81\u3002<\/p>\n
2.\u6709\u4e24\u79cd\u5f52\u7ea6\u7ed3\u679c\u5982A->a\u00b7\u4e0eB->b\u00b7\uff0c\u6839\u636eFollow\u96c6\u5408\u51b3\u5b9a\u5f52\u7ea6\u54ea\u4e00\u4e2a\u3002<\/p>\n
\nLR(1)\u6587\u6cd5<\/h3>\n
*\u628a\u5411\u524d\u770b\u7684\u72b6\u6001\u4e5f\u653e\u5230Item\u91cc\u3002<\/p>\n
[A->\u03b1\u00b7\u03b2,a]<\/code><\/p>\n[S'->\u00b7S,$]<\/code><\/p>\n1.\u4e0d\u5b58\u5728\u79fb\u5165\u3001\u5f52\u7ea6\u51b2\u7a81\u3002<\/p>\n
2.\u4e0d\u5b58\u5728\u5f52\u7ea6\u3001\u5f52\u7ea6\u51b2\u7a81\u3002<\/p>\n
\nLALR(1)<\/h3>\n
\u5408\u5e76\u5411\u524d\u770b\u7684\u7b26\u53f7\u3002<\/p>\n
*\u4e0d\u53ef\u80fd\u6709\u79fb\u5165\u548c\u5f52\u7ea6\u7684\u51b2\u7a81\u3002<\/p>\n
*\u5982\u679c\u4e00\u4e2a\u8bed\u6cd5\u662fSLR(1)\u7684\uff0c\u90a3\u4e48\u5b83\u662fLALR(1)\u7684\u3002<\/p>\n
<\/p>\n
<\/p>\n
\u751f\u6210\u65b9\u6cd5\uff1a\u4eceLR(0)\u5f00\u59cb\u589e\u52a0\u5411\u524d\u770b\u7684\u7b26\u53f7\u3002\uff08**\uff09<\/p>\n
<\/p>\n
\n\u9519\u8bef\u5206\u6790<\/h3>\n
LR(1)\u53d1\u73b0\u9519\u8bef\u65e9\u4e8eLALR(1)\u548cSLR(1)\u3002<\/p>\n
\u5982\u679c\u5b58\u5728\u9519\u8bef\u60c5\u51b5\uff0c\u5c31\u627eGoto\u7684\u60c5\u51b5\uff0c\u5e2e\u52a9\u5b8c\u6210\u8fd9\u4e2a\u5206\u6790\u3002<\/p>\n
\n\u7efc\u5408\u5c5e\u6027<\/h3>\n
\u81ea\u4e0b\u800c\u4e0a\u4f20\u9012\u4fe1\u606f\u3002<\/p>\n
\u8bed\u6cd5\u89c4\u5219\uff1a\u6839\u636e\u53f3\u8fb9\u7b26\u53f7\u8ba1\u7b97\u5de6\u90e8\u88ab\u5b9a\u4e49\u7b26\u53f7\u7684\u7efc\u5408\u5c5e\u6027\u3002<\/p>\n
\u8bed\u6cd5\u6811\uff1a\u6839\u636e\u5b50\u8282\u70b9\u7684\u5c5e\u6027\u548c\u7236\u8282\u70b9\u81ea\u8eab\u7684\u5c5e\u6027\u8ba1\u7b97\u7236\u8282\u70b9\u7684\u7efc\u5408\u5c5e\u6027\u3002<\/p>\n
<\/p>\n
\u7ee7\u627f\u5c5e\u6027<\/h3>\n
\u81ea\u4e0a\u800c\u4e0b\u4f20\u9012\u4fe1\u606f\u3002<\/p>\n
\u8bed\u6cd5\u89c4\u5219\uff1a\u6839\u636e\u53f3\u90e8\u5019\u9009\u5f0f\u4e2d\u7684\u7b26\u53f7\u5c5e\u6027\u548c\u5de6\u90e8\u88ab\u5b9a\u4e49\u7b26\u53f7\u7684\u5c5e\u6027\u8ba1\u7b97\u53f3\u90e8\u5019\u9009\u5f0f\u4e2d\u7684\u7b26\u53f7\u7684\u7ee7\u627f\u5c5e\u6027\u3002<\/p>\n
\u8bed\u6cd5\u6811\uff1a\u6839\u636e\u7236\u8282\u70b9\u548c\u5144\u5f1f\u8282\u70b9\u7684\u5c5e\u6027\u8ba1\u7b97\u5b50\u8282\u70b9\u7684\u7ee7\u627f\u5c5e\u6027\u3002<\/p>\n
\n<\/p>\n","protected":false},"excerpt":{"rendered":"
\u5e38\u7528\u6b63\u5219\u8868\u8fbe\u5f0f 1.\u6570\u5b57 nat = [0-9]+ signalnat = (+|-) […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":[],"categories":[37,16],"tags":[],"_links":{"self":[{"href":"http:\/\/www.magicmipamipa.com\/index.php?rest_route=\/wp\/v2\/posts\/1557"}],"collection":[{"href":"http:\/\/www.magicmipamipa.com\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/www.magicmipamipa.com\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/www.magicmipamipa.com\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/www.magicmipamipa.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=1557"}],"version-history":[{"count":4,"href":"http:\/\/www.magicmipamipa.com\/index.php?rest_route=\/wp\/v2\/posts\/1557\/revisions"}],"predecessor-version":[{"id":1562,"href":"http:\/\/www.magicmipamipa.com\/index.php?rest_route=\/wp\/v2\/posts\/1557\/revisions\/1562"}],"wp:attachment":[{"href":"http:\/\/www.magicmipamipa.com\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=1557"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/www.magicmipamipa.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=1557"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/www.magicmipamipa.com\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=1557"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}
- \u7528[a]\u8868\u793a{a}01<\/sup>\uff0c\u5373a|\u03b5<\/li>\n<\/ul>\n