Re: Fwd: Re: [9fans] samuel (fwd)

["Russ Cox" <rsc@plan9.bell-labs.com>]

I just looked at the cscope documentation.
As Rob said, you can get 90% of cscope from
grep -n, which is convenient to alias as `g':

	g% cat g
	#!/bin/rc
	
	flags=()
	while(! ~ $#* 1 && ~ $1 -*){
		flags=($flags $1);
		shift
	}
	switch($#*){
	case 0
		echo 'usage: g [flags] pattern [files]' >[1=2]
		exit usage
	case 1
		grep -n $flags -- $1 *.[Cbchm] *.cc *.py *.tex *.ms /dev/null \
			|[2] {grep -v '^grep: can''t open \*' >[1=2]; status=''}
	case *
		grep -n $flags -- $* /dev/null
	}

The set of files in ``case 1'' changes from person to
person.  My acme window tags are littered with
g this and g '^that'.

If you don't mind typing small regular expressions
like '^that' and your source code conforms to the 
``function names in definitions start at the beginning
of the line'' convention, then you can usually get 
by without cscope.

If you want to remember a little more, you could
try adding some stuff to g to find function/macro
declarations:

	g% cat h
	#!/bin/rc
	
	rfork e
	if( ~ $#* 0){
		echo 'usage: h name [files]' >[1=2]
		exit usage
	}
	
	pattern=$1
	shift
	files=($*)
	if(~ $#files 0)
		files=(*.h ../port/*.h /sys/include/*.h /sys/include/*/*.h)
	datadef='^[a-z].*[ 	]'^$pattern^'\('
	definedef='^#define[ 	]+'^$pattern^'[ 	]'
	g '('^$datadef^')|('^$definedef^')' $files \
		|[2] {grep -v '^grep: can''t open ' >[1=2]; status=''}
	g% 

or data definitions:

	g% cat def
	#!/bin/rc
	
	rfork e
	if( ~ $#* 0){
		echo 'usage: def name [files]' >[1=2]
		exit usage
	}
	
	pattern=$1
	shift
	files=($*)
	g '^[ 	]*[a-zA-Z0-9_]+[ 	a-zA-Z0-9,]*[, 	]'^$pattern^'($|[^a-zA-Z0-9_])' $files
	g% 

or uses of a particular symbol:

	g% cat sym
	#!/bin/rc
	
	rfork e
	if( ~ $#* 0){
		echo 'usage: sym name [files]' >[1=2]
		exit usage
	}
	
	pattern=$1
	shift
	files=($*)
	g '(^|[^a-zA-Z0-9_])'^$pattern^'($|[^a-zA-Z0-9_])' $files
	g% 

I wrote these last three in a hurry last night just 
for fun, inspired by having seen something similar
a while back in a screen shot in the help paper,
but I'm not sure whether I'll actually use them
or just stick with g.  h might be useful since it
provides a different set of default files.  def and 
sym seem less useful, since g usually turns up
what I want with a minimum of noise.

The other nice thing about g instead of cscope-like
things is that your searches can be arbitrary regexps
rather than whatever cscope happens to provide;
for example, how do you g 'dmactl = 0' in cscope?

Russ