2016-05-31 12:36 GMT+08:00 Andy Chu <andyc...@gmail.com>: > (+toybox list again, since I think you intended that) > > On Mon, May 30, 2016 at 8:26 PM, Roy Tam <roy...@gmail.com> wrote: >> For Coherent 4.2 /bin/sh, please check this out: >> https://github.com/roytam1/mwc-sh >> Since the github mirror doesn't extract everything so I have to do it myself. > >> May be you missed yash shell. >> https://yash.osdn.jp/index.html.en > > > OK, that didn't take long! Thanks Roy.
and the latest minix /bin/sh is here: https://github.com/minix3/minix/tree/R3.1.6/commands/sh > > I looked at both of these, and they are indeed quite complete POSIX > compliant Bourne shells. Coherent sh is ~11K LOC, while yash is ~43K > LOC, including its own line editing library. > > Coherent sh actually uses yacc like bash, and I believe this comment > in parse.y is related to the same pitfalls that bash ran into: > > """ > In the original grammar, no distinction between simple command and > compound > commands was made. This, along with the right-recursive formulation of > the > command grammar, created a need for lookahead that defeated the > complex > machinery for context-sensitive lexing that is required. > """ > > My reading of this is: "we subsetted the POSIX grammar, because if you > use the full grammar, it becomes really difficult to parse command > substitution -- matching $( and )". bash solved this by duplicating a > lot of the parser, as previously discussed. > > In my defense, Coherent sh was only open sourced in 2015! And > development apparently stopped in 1995. > > yash looks like it started as a student project in 2007, and has > evolved into a comprehensive POSIX compliant shell, and is still under > active development. It even has an Ubuntu package (yash)! > > I updated this section of Wikipedia based on this new information: > https://en.wikipedia.org/wiki/Unix_shell#Bourne_shell > > (I had done a lot of research on this, including in some books, but > yeah I definitely missed those two completely.) > > OK, so does anyone want to dispute my new claim that there are only > 6-7 open source code lineages, and 3-4 started without paid labor > (hush is still TBD)? > > Andy _______________________________________________ Toybox mailing list Toybox@lists.landley.net http://lists.landley.net/listinfo.cgi/toybox-landley.net