mmh, much more clear now, yes. So you need to deal with a perl part and a lisp part

joining some dots that could (or not) to be useful for you

If you want to pick-up error messages from json, maybe you could wish to explore the functions available in the json package. i.e json-error

(require 'json) 
;; create data lisp structures from json files

[download]
or, in emacs... 
m-x load-library json
apropos json

[download]

In reply to Re: Coverage tool visibility within emacs by pvaldes
in thread Coverage tool visibility within emacs by MidLifeXis

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