Once upon a time (2014-2015) I served on the Canadian Well Logging Society's (CWLS) executive committee as the Committee/Website Chair. The CWLS is a non-profit professional organisation in the Oil & Gas industry and the executive committee consists of elected volunteers.
I volunteered for the position of Website Chair because of family/friend connections (members) to the organisation and also because their website was 'Under Construction' for quite a long time. I wanted to see if I could help advise and/or participate in getting it back online. To make a long story short, I was able to help but it was a slow process... but I digress, back to the CWLS LAS file format.
The CWLS committee was responsible for spear-heading an industry wide effort to standardise the format of oil well logging digital data. This format is known as the Log ASCII Standard or LAS for short. It was created back when XML was becoming popular but felt to be too verbose and the INI format too limiting. JSON was not developed at that time, to my knowledge. I am not sure what else the CWLS committee considered back then.
One of the questions that periodically comes up is that of open source libraries for the LAS specification. Here is a recent reply (names removed for privacy) I penned on this topic.
I have cc'd the current CWLS exec website chair for reference. I was on the CWLS exec committee a few years ago and am a software developer so have an interest in your question and hope I can provide some assistance on what I have found.
To first answer your question directly, the practice has been for you to develop your own readers as the CWLS committee is a volunteer organisation and does not have the resources to develop or maintain software libraries. The LasApps free software available on the site is there because of a member's generosity and interest in the CWLS specification.
Having said that, there still appear to be some independent efforts (ie. not connected with the CWLS committee) to create open source readers/libraries for the LAS file format. Re-doing my search from a few years ago turns up:
Python - https://lasio.readthedocs.io/en/latest/index.html
Ruby - https://github.com/gpcarmo/cwls-las-reader
For Java the question on stackoverflow:
Just points to the commercial Petroware library:
I have not run across anything else significant for other languages, but perhaps was not looking hard enough.
Which programming language(s) are you interested in?
Personally, I ended up writing my own reader in Java because at that time I could not find any reasonable open source Java libraries and naively thought 'how hard can it be?' ... as you may already know, since the LAS format is text based, the challenge becomes handling files which are close to the spec but not quite - does one fail or fix/absorb the issue. I continue to enhance my reader to handle the edge cases as I encounter them :-).
I wrote my reader to handle version 3.0 files but in practice mostly run across LAS version 2.0. Another local Calgary company who's product handles LAS files has echoed the same.
If you would like to chat more, feel free to call or email.
Hope this helps you decide on your approach.