add a lispy option for tracing? #57
Description
Some of the quirks I saw when I tried source maps got me thinking...
What about an option for the lispy command to generate the code in a "trace" mode?
Such that when you run it outputs a trace of the program run?
Where (ideally) this might show the lispy source (and maybe the lispy source line numbers and javascript line numbers? since maybe that's not too hard since the sourcemap support in theory has that available already?)
Not that I've given it much thought - maybe less ambitious but still helpful is just a little api for log statements that are only included in the generated code if you've compiled with this special "debug"/"trace" option enabled?
To be a more concrete - I was thinking about this in the context of the "await" macro I just posted about in issue #56.
What if the macros had some optional trace statements that normally expand to nothing/no-ops but expand to console.log statements - output in the generated code - when the lispy compiler got this "trace" mode option:
So e.g.:
(macro await (result asynccall rest...)
(trace "await for" ^result "from" ^asynccall)
(~@asynccall (function (err ~result)
(trace "got" ^result "from" ^asynccall ":" ~result)
~rest...)))
The above is just to illustrate the idea it doesn't actually work of course.
In particular in the above I've used a hypothetical e.g. "^result" to indicate "I want the macro argument as a quoted string" (which is what is needed for a console.log statement).
As opposed to the normal "~result" to get the macro argument unquoted as needed for actual generated code.
is there already a way to do domething similar I wonder?
I can see where the above might be questioned as too simple, but if it were also supported through the "keyword" handling in the "lib/ls.js" file...
And maybe even allowed for a few different tracing "levels".
I could see this being very helpful when developing real programs, esp. where complex control flow and asyncrony is involved.