Valid numeric entity refused by xexpr->xml

Questions & Answers
1

hello,

i'm facing this strange error :

xexpr->xml: contract violation;
 Not an Xexpr. Expected a string, symbol, valid numeric entity, comment, processing instruction, or list, given 2.2384341637010676

Context:
'(DATA
  (TABLEDATA
   (TR
    (TD "2021-01-01T00:00:00.000")
    (TD "-5.226162")
    (TD "-0.133805")
    (TD "1.462782")
    (TD 2.2384341637010676)
    (TD 0.7829181494661922)
    (TD 4.069395017793594))
   (TR
    (TD "2021-01-01T00:01:00.000")
    (TD "-5.239695")
    (TD "-0.133871")
    (TD "1.446325")
    (TD 2.0249110320284696)
    (TD 0.9128113879003559)
    (TD 3.9733096085409256))


....


(TR
    (TD "2021-01-01T23:58:00.000")
    (TD "-0.222710")
    (TD "0.016590")
    (TD "-2.168841")
    (TD 15.09608540925267)
    (TD -1.2188612099644127)
    (TD 15.701067615658364))
   (TR
    (TD "2021-01-01T23:59:00.000")
    (TD "-0.170992")
    (TD "0.015211")
    (TD "-2.140229")
    (TD 15.45373665480427)
    (TD -1.3558718861209964)
    (TD 16.144128113879002))))
  in: the 1st argument of
      (->
       xexpr/c
       (or/c
        pcdata?
        element?
        entity?
        comment?
        cdata?
        p-i?
        permissive/c))
  contract from: 
      <collects>/xml/private/xexpr.rkt
  blaming: /opt/homebrew/var/www/drive/interpole_fields
   (assuming the contract is correct)
  at: <collects>/xml/private/xexpr.rkt:102:2
  context...:
   /Applications/Racket/collects/racket/contract/private/blame.rkt:350:0: raise-blame-error
   /Applications/Racket/collects/racket/private/more-scheme.rkt:163:2: select-handler/no-breaks
   /Applications/Racket/collects/racket/contract/combinator.rkt:298:9
   /Applications/Racket/collects/racket/contract/private/arrow-val-first.rkt:486:18
   /opt/homebrew/var/www/drive/interpole_fields:249:2
   body of "/opt/homebrew/var/www/drive/interpole_fields"


....

it seems my 'numeric entity' 2.2384341637010676 is refused by xexpr->xml :

Welcome to DrRacket, version 8.14 [cs].
Language: racket, with debugging; memory limit: 8192 MB.
(require xml
		 (except-in 2htdp/batch-io xexpr?))
> xexpr->xml
#<procedure:xexpr->xml>

> (xexpr->xml '(TD "2.2384341637010676"))
(element 'racket 'racket 'TD '() (list (pcdata 'racket 'racket "2.2384341637010676")))

i do not understand why? seems a bug but probably i do not understand something...

2

You need to pass floating points as strings.

https://docs.racket-lang.org/xml/index.html#(def._((lib._xml%2Fprivate%2Fxexpr-core..rkt)._xexpr~3f))

Note that "valid numeric entity" refers to what's accepted by valid-char?.

3

reading the doc , i understand it only accept integers numbers, the term 'numeric entity' could be understant as all type of numbers, in fact adding a number->stringin the code solve the problem:

`(TR (TD ,time-stamp)
				    (TD ,X_MSO)
				    (TD ,Y_MSO)
				    (TD ,Z_MSO)
				    (TD ,(number->string
					  (cal
					   (string->number VALx))))
				    (TD ,(number->string
					  (cal
					   (string->number VALy))))
				    (TD ,(number->string
					  (cal
					   (string->number VALz)))))