add side-effect piping (#30)
refine docs
add tests
refine vignettes
update info
update readme
update readme
update side-effect syntax (#30)
update vignettes (#30)
fix and update readme (#30)
refine pkg info
deprecate lambda expression in form of (x -> expr) (#31)
deprecate Pipe(...)$fun() (#29)
update info
update info
less lines
rearrange code
implement generic functions for Pipe (#32)
add utils
refine generic functions for Pipe (#32)