2.5 KiB
Implementation details
- fq uses a gojq fork that can be found at https://github.com/wader/gojq/tree/fq (the "fq" branch)
- cli readline uses raw mode so blocks ctrl-c to become a SIGINT
- TODO:
scopeandscopedumpfunctions used to implement REPL completion - TODO: Custom object interface used to traverse fq's field tree and to allowing a terse syntax for comparing and working with fields, accessing child fields and special properties like
_range.
Decoder implementation help
-
Main goal in the end is to produce a tree that is user-friendly and easy to work with. So there are always excepts to these rules and sometimes it might be better to let the decoder code be a bit ugly over producing a tree that is hard to understand.
-
Try use same names, symbols, constant number base etc as in specification
-
TODO: Decode only what you know. If possible let "parent" decide what to do with unknown bits by using
*Decode*Len/Range/Limitfuncitions -
Use sub decoders if possible for frames, metadata etc. You can pass data between them. Also makes it possible to call them separately
-
Try to no decode to much as one field or value. A length encoded int could be two fields, a flags byte can be struct with bit fields.
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Try to have add symbols for all named constants.
Debug
Send log package output and stderr to a file that can be tail -f:ed:
LOGFILE=/tmp/log go run main.go ... 2>>/tmp/log
gojq execution debug:
GOJQ_DEBUG=1 go run -tags debug main.go ...
From start to decoded value
main:main()
cli.Main(default registry)
interp.New(registry, std os interp implementation)
interp.(*Interp).Main()
interp.jq _main/0:
args.jq _args_parse/2
populate filenames for input/0
interp.jq inputs/0
foreach valid input/0 output
interp.jq open
funcs.go _open
interp.jq decode
funcs.go _decode
decode.go Decode(...)
...
interp.jq eval expr
funcs.go _eval
interp.jq display
funcs.go _display
for interp.(decodeValueBase).Display()
dump.go
print tree
empty output