fork(1) download
copy 
  1. ;; Define helper functions
  2. (define (drop-while pred lis)
  3.   (if (or (null? lis) (not (pred (car lis))))
  4.       lis
  5.       (drop-while pred (cdr lis))))
  6.  
  7. (define (take-while pred lis)
  8.   (define (take-while-helper pred lis result)
  9.     (if (and (not (null? lis)) (pred (car lis)))
  10.         (take-while-helper pred (cdr lis) (cons (car lis) result))
  11.         (reverse result)))
  12.   (take-while-helper pred lis '()))
  13.  
  14. (define (char-other? ch)
  15.   (not (or (= (char->integer ch) 91)
  16.            (= (char->integer ch) 93)
  17.            (= (char->integer ch) 40)
  18.            (= (char->integer ch) 41)
  19.            (= (char->integer ch) 32)
  20.            (= (char->integer ch) 10))))
  21.  
  22. (define (process-other chars)
  23.   (and (not (null? chars))
  24.        (let* ((token-chars (take-while char-other? chars))
  25.               (rest (drop-while char-other? chars)))
  26.          (list token-chars rest))))
  27.  
  28. ;; Custom function to check if all elements in a list are characters
  29. (define (all-char? lis)
  30.   (if (null? lis)
  31.       #t
  32.       (and (char? (car lis)) (all-char? (cdr lis)))))
  33.  
  34. ;; Function to tag tokens with their type
  35. (define (tag-token type value)
  36.   (list type value))
  37.  
  38. ;; Functions to take and drop elements from the list
  39. (define (take n lis)
  40.   (if (or (<= n 0) (null? lis))
  41.       '()
  42.       (cons (car lis) (take (- n 1) (cdr lis)))))
  43.  
  44. (define (drop n lis)
  45.   (if (or (<= n 0) (null? lis))
  46.       lis
  47.       (drop (- n 1) (cdr lis))))
  48.  
  49. ;; Functions for Dot Count
  50. (define (process-dots chars)
  51.   (let* ((dot-chars (take-while (lambda (ch) (char=? ch (integer->char 46))) chars))  ; char 46 is '.'
  52.          (num-dots (length dot-chars))
  53.          (rest (drop-while (lambda (ch) (char=? ch (integer->char 46))) chars)))
  54.     (list num-dots rest)))
  55.  
  56. ;; Define main tokenize function with integrated new functions
  57. (define (tokenize input)
  58.   (let loop ((chars (string->list input)) (tokens '()))
  59.     (cond
  60.       ((null? chars) (reverse tokens))  ; Return the reversed tokens
  61.       ((char=? (car chars) (integer->char 91))  ; Handle opening bracket [
  62.        (loop (cdr chars) (cons (tag-token 'open-bracket "[") tokens)))
  63.       ((char=? (car chars) (integer->char 93))  ; Handle closing bracket ]
  64.        (loop (cdr chars) (cons (tag-token 'close-bracket "]") tokens)))
  65.       ((char=? (car chars) (integer->char 40))  ; Handle opening parenthesis
  66.        (loop (cdr chars) (cons (tag-token 'open-parenthesis "(") tokens)))
  67.       ((char=? (car chars) (integer->char 41))  ; Handle closing parenthesis
  68.        (loop (cdr chars) (cons (tag-token 'close-parenthesis ")") tokens)))
  69.       ((char=? (car chars) (integer->char 32))  ; Skip spaces
  70.        (loop (cdr chars) tokens))
  71.       ((char=? (car chars) (integer->char 46))  ; Handle dots (.)
  72.        (let* ((result (process-dots chars))
  73.               (num-dots (car result))
  74.               (rest (cadr result)))
  75.          (loop rest (cons (tag-token 'dots num-dots) tokens))))  ; Use a tagged list structure
  76.       (else
  77.        (let* ((result (process-other chars))
  78.               (token (car result))
  79.               (rest (cadr result)))
  80.          (loop rest (cons (tag-token 'other token) tokens)))))) ) ; End of tokenize function
  81.  
  82. (define (simplify-for-output x) x)
  83.  
  84. (define (dots? x) (and (pair? x) (pair? (car x))
  85.                     (eq? 'dots (caar x))))
  86.  
  87. (define (dot-count x) (cadr x))
  88.  
  89. ;; Function to gather and tag tokens based on dots
  90. (define (process-final tokens)
  91.   (define (process-helper reversed-tokens forward-tail)
  92.     (cond
  93.       ((null? reversed-tokens)
  94.        (simplify-for-output forward-tail))
  95.       ((dots? reversed-tokens)
  96.        (let* ((count (dot-count (car reversed-tokens)))
  97.               (collected (tag-token 'final (take count forward-tail)))
  98.               (the-rest (drop count forward-tail))
  99.               (the-tail (append
  100.                           collected
  101.                           (list
  102.                             (tag-token 'right-parenthesis ")"))
  103.                           the-rest)))
  104.           the-tail))
  105.       (else (process-helper
  106.               (cdr reversed-tokens)
  107.               (cons (car reversed-tokens) forward-tail)))))
  108.   (process-helper (reverse tokens) '()))
  109.  
  110.  
  111. ;; Example usage
  112. (define input "1 (). 2 3")
  113.  
  114. ;; Tokenize the input
  115. (let ((tokens (tokenize input)))
  116.   (write tokens)  ; Write the intermediate tokenized output for debugging
  117.   (newline)(newline)
  118.   (write (process-final tokens)))  ; Return the final processed output
  119.  
Success #stdin #stdout 0.01s 8032KB
comments (?)
stdin
copy 
Standard input is empty
stdout
copy 
((other (#\1)) (open-parenthesis "(") (close-parenthesis ")") (dots 1) (other (#\2)) (other (#\3)))

(final ((other (#\2))) (right-parenthesis ")") (other (#\3)))
https://ideone.com/BjqugT
language:
Scheme (chicken 4.13)
created:
6 days ago
visibility:
public

Share or Embed source code

Discover > Sphere Engine API

The brand new service which powers Ideone!

Discover > IDE Widget

Widget for compiling and running the source code in a web browser!