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(define-module (guix-data-service model utils)
#:use-module (srfi srfi-1)
#:use-module (ice-9 match)
#:use-module (ice-9 vlist)
#:use-module (ice-9 receive)
#:use-module (squee)
#:export (quote-string
value->quoted-string-or-null
value->sql-boolean
non-empty-string-or-false
exec-query->vhash
two-lists->vhash
deduplicate-strings
group-list-by-first-n-fields))
(define (quote-string s)
(string-append "$STR$" s "$STR$"))
(define (value->quoted-string-or-null value)
(if (string? value)
(string-append "$STR$" value "$STR$")
"NULL"))
(define (value->sql-boolean v)
(match v
((? boolean? x)
(if x "TRUE" "FALSE"))
((? string? x)
(if (or (string=? x "t")
(string=? x "TRUE"))
"TRUE"
"FALSE"))))
(define (non-empty-string-or-false s)
(if (string? s)
(if (string-null? s)
#f
s)
#f))
(define (exec-query->vhash conn query field-function value-function)
(fold (lambda (row result)
(vhash-cons (field-function row)
(value-function row)
result))
vlist-null
(exec-query conn query)))
(define (two-lists->vhash l1 l2)
(fold (lambda (key value result)
(vhash-cons key value result))
vlist-null
l1
l2))
(define (deduplicate-strings strings)
(pair-fold
(lambda (pair result)
(if (null? (cdr pair))
(cons (first pair) result)
(if (string=? (first pair) (second pair))
result
(cons (first pair) result))))
'()
(sort strings string<?)))
(define (group-list-by-first-n-fields n lists)
(fold (lambda (lst groups)
(receive (key vals)
(split-at lst n)
(append
(alist-delete key groups)
`((,key . ,(append
(or (assoc-ref groups key)
'())
(list vals)))))))
'()
lists))
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