1  static const char *const GUILE_module_defn = " \
       2  (define (to-string-maybe x) \
       3    (cond \
       4     ((or (not x) \
       5          (unspecified? x) \
       6          (variable? x) \
       7          (null? x) \
       8          (and (string? x) (string-null? x))) \
       9      #f) \
      10     ((eq? x #t) \"#t\") \
      11     ((or (symbol? x) (number? x)) \
      12      (object->string x)) \
      13     ((char? x) \
      14      (string x)) \
      15     ((and (string? x) (string-every char-set:printing x)) \
      16      x) \
      17     (else (error \"Unknown object:\" x)))) \
      18  (define (obj-to-str x) \
      19    (let ((acc '())) \
      20      (define (walk x) \
      21        (cond ((pair? x) (walk (car x)) (walk (cdr x))) \
      22              ((to-string-maybe x) => (lambda (s) (set! acc (cons s acc)))))) \
      23      (walk x) \
      24      (string-join (reverse! acc)))) \
      25  (define (gmk-var v) \
      26    (gmk-expand (format #f \"$(~a)\" (obj-to-str v)))) \
      27  (export gmk-expand gmk-eval gmk-var) \
      28  ";