Лексический анализ

Вячин Александр/README.md

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+# Лексический анализ
+## Ссылка на видеоразбор
+https://youtu.be/NKhwfK0PurY
+## Код из книги
+    type token = Name of string| Num of string | Other of string;;
+    let lex =
+        let several p = many ( some p ) in
+        let lowercase_letter s = " a" <= s & s <= " z " in
+        let uppercase_letter s = "A" <= s & s <= "Z" in
+        let letter s = lowercase_letter s or uppercase_letter s in
+        let alpha s = letter s or s = "_" or s = " ’ " in
+        let digits = " 0" <= s & s <= "9 " in
+        let alphanum s = alpha s or digit s in
+        let spaces = s = "␣ " or s = " \n" or s = "\ t " in
+        let collect (h , t) = h^( it list ( prefix ^) t " " ) in
+        let rawname =
+        some alpha ++ several alphanum >> (Name o collect ) in
+        let rawnumeral =
+        some digit ++ several digit >> (Num o collect) in
+        let raw other = some (K true) >> Other in
+        let token =
+        (rawname | | rawnumeral | | rawother) ++ several space >> fst in
+        let tokens = (several space ++ many token ) >> snd in
+        let all tokens = (tokens ++ finished) >> fst in
+        fst o all token s o explode;;
+        

Вячин Александр/lekz_analyz.rkt

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+#lang racket
+;Лексический анализ Вячин 0307
+
+(require parser-tools/lex)
+(require (prefix-in : parser-tools/lex-sre))
+;библиотеки для работы с функциями
+
+(define calc-lexer
+  (lexer
+   [(:+ (:or (char-range #\a #\z) (char-range #\A #\Z)))
+    (cons `(NAME ,(string->symbol lexeme)) (calc-lexer input-port))]
+   ;символы от a-z и от A-Z
+   [#\( (cons '(LPAR) (calc-lexer input-port))]
+   ;левая скобка
+   [#\) (cons '(RPAR) (calc-lexer input-port))]
+   ;правая скобка
+   [(:+ (char-range #\0 #\9))
+    (cons `(CONST ,(string->number lexeme)) (calc-lexer input-port))]
+   ;цифры от 0-9 
+   [(:or #\+ #\- #\/ #\* #\^) (cons `(OP ,(string->symbol lexeme)) (calc-lexer input-port))]
+   ;операции "+", "-", "/", "*", "^"
+   [whitespace (calc-lexer input-port)] 
+   ;пробелы не заносятся в список лексем
+   [(eof) '()]))
+   ;конец входной последовательности
+
+(define (lex n)(calc-lexer(open-input-string n)))
+;для удобного пользования: (lex "*входная последовательность*")
+
+
+
+
+