\u5909\u6570\u5165\u308c\u3066\u307f\u305f\u3053\u3068\u4ee5\u5916\u306f\u3001\u524d\u56de<\/a>\u306e\u3082\u306e\u3068\u540c\u3058\u3002\u30a8\u30e9\u30fc\u51e6\u7406\u306f\u3044\u3044\u304b\u3052\u3093\u3067\u3059\u3002\u3044\u308d\u3044\u308d\u307e\u305a\u3044\u3068\u3053\u308d\u304c\u3042\u308b\u306e\u306f\u308f\u304b\u3063\u3066\u3044\u308b\u3051\u308c\u3069\u3001\u9aa8\u5b50\u306e\u5206\u304b\u308a\u3084\u3059\u3055\u3067\u306f\u3053\u3093\u306a\u3082\u306e\u306e\u65b9\u304c\u308f\u304b\u308a\u3084\u3059\u3044\u304b\u3082\u30fb\u30fb\u30fb<\/p>\n \u4e0a\u8a18\u3001PEG \u306a\u3089\u3073\u306b Common Lisp \u306e\u30b3\u30fc\u30c9\u306f\u3053\u306e\u30b5\u30a4\u30c8\u3067\u63d0\u793a\u3057\u3066\u3044\u308b\u30b3\u30fc\u30c9\u306e\u57fa\u672c License<\/a> \u306b\u63b2\u3052\u308b\u3082\u306e\u306b\u5f93\u3046\u3002<\/p>\n <\/p>\n","protected":false},"excerpt":{"rendered":" PEG \u5b9a\u7fa9 \u5909\u6570\u5165\u308c\u3066\u307f\u305f\u3053\u3068\u4ee5\u5916\u306f\u3001\u524d\u56de\u306e\u3082\u306e\u3068\u540c\u3058\u3002\u30a8\u30e9\u30fc\u51e6\u7406\u306f\u3044\u3044\u304b\u3052\u3093\u3067\u3059\u3002\u3044\u308d\u3044\u308d\u307e\u305a\u3044\u3068\u3053\u308d\u304c\u3042\u308b\u306e\u306f\u308f\u304b\u3063\u3066\u3044\u308b\u3051\u308c\u3069\u3001\u9aa8\u5b50\u306e\u5206\u304b\u308a\u3084\u3059\u3055\u3067\u306f\u3053\u3093\u306a\u3082\u306e\u306e\u65b9\u304c\u308f\u304b\u308a\u3084\u3059\u3044\u304b\u3082\u30fb\u30fb\u30fb statement & … \u7d9a\u304d\u3092\u8aad\u3080 statement <- spaces (definition \/ expression) spaces\r\n\r\ndefinition <- identifier spaces define spaces expression\r\n\r\nexpression <- (expression spaces add spaces multiplicative_expression)\r\n \/ (expression spaces sub spaces multiplicative_expression)\r\n \/ multiplicative_expression\r\n\r\nmultiplicative_expression <-\r\n (multiplicative_expression spaces mult spaces primary_expression)\r\n \/ (multiplicative_expression spaces div spaces primary_expression)\r\n \/ (multiplicative_expression spaces mod spaces primary_expression)\r\n \/ primary_expression\r\n\r\nprimary_expression <- constant\r\n \/ identifier\r\n \/ ('(' spaces expression spaces ')')\r\n\r\nidentifier <- identifier_start identifier_continuas*\r\n\r\nidentifier_continuas <- alphabet \/ underscore \/ digit\r\n\r\nidentifier_start <- alphabet \/ underscore\r\n\r\nconstant <- integer_constant\r\n\r\ninteger_constant <- decimal_integer_constant\r\n\r\ndecimal_integer_constant <- sign_part? digit+\r\n\r\nsign_part <- '+' \/ '-'\r\n\r\n## Lex!\r\n\r\nalphabet <- [a-zA-Z]\r\n\r\ndigit <- [0-9]\r\n\r\nunderscore <- '_'\r\n\r\noperator <- add \/ sub \/ mult \/ div \/ mod \/ define\r\n\r\n# operator\r\n\r\nadd <- '+'\r\n\r\nsub <- '-'\r\n\r\nmult <- '*'\r\n\r\ndiv <- '\/'\r\n\r\nmod <- '%'\r\n\r\ndefine <- '='\r\n\r\n#\r\n\r\nspaces <- [ \\t]*\r\n\r\neol <- '\\r\\n' \/ '\\n' \/ '\\r' \/ eof\r\n\r\neof <- !.\r\n\r\n<\/code><\/pre>\nLisp \u30b3\u30fc\u30c9<\/h2>\n
(defvar id-table)\r\n\r\n(defun clean-identifier-table ()\r\n (setf id-table (make-hash-table :test #'equal)))\r\n\r\n(clean-identifier-table)\r\n\r\n(peg-compile\r\n (parse-peg-file \"foo.peg\"))\r\n\r\n(defun val_digits (x &optional (y 0))\r\n (cond ((not x) y)\r\n ('t (val_digits (cdr x) (+ (* 10 y) (parse-integer (cadr (car x))))))))\r\n\r\n(def-peg-fun statement (x) (ast-eval (second x)))\r\n\r\n(defun id-cont-key (x)\r\n (if (car x)\r\n (concatenate 'string (cadr (cadr (car x))) (id-cont-key (cdr x)))))\r\n\r\n(defun id-key (x)\r\n (concatenate 'string (cadr (cadr (car x))) (id-cont-key (cadr x))))\r\n\r\n(defun id-value (x) (fifth x))\r\n\r\n(def-peg-fun identifier (x)\r\n (let* ((id-str (id-key x)) (res (gethash id-str id-table)))\r\n (if res\r\n (ast-eval res)\r\n (format 't \"Undefined identifier: ~S\" id-str))))\r\n\r\n(def-peg-fun definition (x)\r\n (setf (gethash (id-key (cadr (car x))) id-table) (id-value x)))\r\n\r\n(def-peg-fun expression (x)\r\n (cond ((atom (car x)) (ast-eval x)) ; x == MULTIPLICATIVE_EXPRESSION\r\n ((eq 'add (car (third x))) (+ (ast-eval (car x)) (ast-eval (fifth x))))\r\n ((eq 'sub (car (third x))) (- (ast-eval (car x)) (ast-eval (fifth x))))\r\n ('t (break))))\r\n\r\n(def-peg-fun multiplicative_expression (x)\r\n (cond ((atom (car x)) (ast-eval x)) ; x == PRIMARY_EXPRESSION\r\n ((eq 'mult (car (third x))) (* (ast-eval (car x)) (ast-eval (fifth x))))\r\n ((eq 'div (car (third x))) (\/ (ast-eval (car x)) (ast-eval (fifth x))))\r\n ((eq 'mod (car (third x))) (mod (ast-eval (car x)) (ast-eval (fifth x))))\r\n ('t (progn (format 't \"MULTIPLICATIVE EXPRESSION ERROR: ~A\" (third x))))))\r\n\r\n(def-peg-fun primary_expression (x)\r\n (cond ((eq 'constant (car x)) (ast-eval x))\r\n ((eq 'identifier (car x)) (ast-eval x))\r\n ('t (ast-eval (third x))))) ; open-r-brachet spaces EXPRESSION spaces close-r-bracket\r\n\r\n(def-peg-fun constant (x) (ast-eval x))\r\n\r\n(def-peg-fun integer_constant (x) (ast-eval x))\r\n\r\n(def-peg-fun decimal_integer_constant (x)\r\n (cond ((not (car x)) (val_digits (cadr x)))\r\n ((equal (cadr (car x)) \"-\") (- (val_digits (cadr x))))\r\n ('t (val_digits (cadr x)))))<\/code><\/pre>\n\u3053\u3053\u3067\u306e\u30b3\u30fc\u30c9\u306e\u30e9\u30a4\u30bb\u30f3\u30b9\u306b\u3064\u3044\u3066<\/h2>\n