json_uncomment

Cross-platform utility to strip comments and optionally minify JSON

why

There are many JSON uncomment utilities, but none I tried worked for my purposes:

• Many had fundamental problems such as not working for all JSON. For example, it's not possible to properly strip comments using regular expressions, and yet many libraries try to do exactly that (such as vaidik/commentjson#16)
• Every utility I tried would change the size of the output, which is a problem for me because where possible I prefer to use JSON schema validation, and with these utilies that change the input size, location tracking was useless because locations in the stripped JSON could not be translated into locations in the original input

how

json_uncomment uses a very simple approach to solve the above issues. First, it uses a proper lexer to parse the JSON. Second, it provides an option to retain input size (and therefore locations other than for comments). Features include:

• very small code base of ~200 lines of code, much of which are just lex instructions (which should be easily portable to any language)
• can be compiled / run on any platform and easily invoked by virtually any language that can use a shared lib and/or call a shell and pipe stdin/stdout
• by default, the output has the same number of characters as the input (comments are replaced with whitespace), so that any subsequent schema validation location tracking will properly corresponds to the original input
• in optional "compact" mode, extraneous whitespace is not emitted

performance

json_uncomment is ultra-lite and extremely fast. It reads via stream, writes to stream, and never asks for more memory no matter how much big the input and no matter how long the strings in the input are

tracking

json_uncomment tracks line and column numbers in order to provide location information output messages (in addition, json_uncomment_untracked can be built as a slightly more streamlined version that excludes the tracking feature)

building

To build, run: make [RELEASE=1] json_uncomment # normal version make [RELEASE=1] json_uncomment_untracked # version without tracking feature

To cross-compile using mingw64, run: make [RELEASE=1] WIN=1

The optional RELEASE=1 flag will build with full compiler optimizations