[TUHS] Proliferation of options is great simplification of pipes, really?

[Brantley Coile]

#!/bin/rc
# doctype:  synthesize proper command line for troff

troff=troff
eqn=eqn
prefer=prefer
opt=''
dev=''
while(~ $1 -*){
	switch($1){
	case -n;
		troff=nroff
		eqn=neqn
		prefer='prefer -n'
	case -T
		dev=$1
	case -*
		opt=$opt' $1'
	}
	shift
}
ifs='
'{
	files=`{echo $*}
}
grep -h '\$LIST|\|reference|Jp|^\.(EQ|TS|\[|PS|IS|GS|G1|GD|PP|BM|LP|BP|PI|cstart|begin|TH...|TI)|^\.P$' $* |
sort -u |
awk '
BEGIN	{ files = "'$"files'" }
/\$LIST/ { e++ }
/^\.PP/	{ ms++ }
/^\.LP/	{ ms++ }
/^\.EQ/	{ eqn++ }
/^\.TS/	{ tbl++ }
/^\.PS/	{ pic++ }
/^\.IS/	{ ideal++ }
/^\.GS/ { tped++ }
/^\.G1/ { grap++; pic++ }
/^\.GD/ { dag++; pic++ }
/^\.\[/	{ refer++ }
/\|reference/ { prefer++ }
/^\.cstart/ { chem++; pic++ }
/^\.begin +dformat/ { dformat++; pic++ }
/^\.TH.../ { man++ }
/^\.BM/ { lbits++ }
/^\.P$/	{ mm++ }
/^\.BP/	{ pictures++ }
/^\.PI/	{ pictures++ }
/^\.TI/	{ mcs++ }
/^\.ft *Jp|\\f\(Jp/ { nihongo++ }
END {
	x = ""
	if (refer) {
		if (e)	x = "refer/refer -e " files " | "
		else	x =  "refer/refer " files "| "
		files = ""
	}
	else if (prefer) { x = "cat " files "| '$prefer'| "; files = "" }
	if (tped)  { x = x "tped " files " | "; files = "" }
	if (dag)  { x = x "dag " files " | "; files = "" }
	if (ideal) { x = x "ideal -q " files " | "; files = "" }
	if (grap)  { x = x "grap " files " | "; files = "" }
	if (chem)  { x = x "chem " files " | "; files = "" }
	if (dformat)  { x = x "dformat " files " | "; files = "" }
	if (pic)   { x = x "pic " files " | "; files = "" }
	if (tbl)   { x = x "tbl " files " | "; files = "" }
	if (eqn)   { x = x "'$eqn' '$dev' " files " | "; files = "" }
	x = x "'$troff' "
	if (man) x = x "-man"
	else if (ms) x = x "-ms"
	else if (mm) x = x "-mm"
	if (mcs) x = x " -mcs"
	if (lbits) x = x " -mbits"
	if (pictures) x = x " -mpictures"
	if (nihongo) x = x " -mnihongo"
	x = x " '$opt' '$dev' " files
	print x
}'

> On Feb 23, 2021, at 5:42 AM, Jaap Akkerhuis <jaapna at xs4all.nl> wrote:
> 
> 
> 
>> On Feb 23, 2021, at 3:47, M Douglas McIlroy <m.douglas.mcilroy at dartmouth.edu> wrote:
>> 
>>> I can imagine a simple perl (or python or whatever) script that would run
>>> through groff input [and] determine which preprocessors are actually
>>> needed ...
>> 
>> Brian imagined such and implemented it way back when. Though I used
>> it, I've forgotten its name. One probably could have fooled it by
>> tricks like calling pic only in a .so file and perhaps renaming .so.
>> But I never heard of it failing in real life. It does impose an extra
>> pass over the input, but may well save a pass compared to the
>> defensive groff -pet that I often use or to the rerun necessary when I
>> forget to mention some or all of the filters.
> 
> 
> If I remember correctly, it was an awk script printing out the
> suggested pipeline to use.  One could then cut and paste that line.
> 
> 	jaap