$foo in tags - here only for reference.

src/cmd/acme/exec.c

@@ -159,6 +159,8 @@ execute(Text *t, uint aq0, uint aq1, int external, Text *argt)
 				q1++;
 			while(q0>0 && isexecc(c=textreadc(t, q0-1)) && c!=':')
 				q0--;
+			if(q0>0 && textreadc(t, q0-1)=='$')
+				q0--;
 			if(q1 == q0)
 				return;
 		}

src/cmd/acme/fns.h

@@ -92,6 +92,9 @@ char*	edittext(Window*, int, Rune*, int);
 void		flushwarnings(void);
 void		startplumbing(void);
 
+int		expandenv(Rune**, uint*);
+int		abbrevenv(Rune**, uint*);
+
 Runestr	runestr(Rune*, uint);
 Range range(int, int);
 

src/cmd/acme/fsys.c

@@ -145,6 +145,8 @@ fsysproc(void *v)
 		if(n <= 0){
 			if(closing)
 				break;
+			if(n == 0)
+				werrstr("short read");
 			error("i/o error on server channel");
 		}
 		if(x == nil){

src/cmd/acme/look.c

@@ -15,6 +15,8 @@
 #include "dat.h"
 #include "fns.h"
 
+#define debug 0
+
 FsFid *plumbsendfid;
 FsFid *plumbeditfid;
 
@@ -456,10 +458,12 @@ dirname(Text *t, Rune *r, int n)
 	b = nil;
 	if(t==nil || t->w==nil)
 		goto Rescue;
+	if(n>=1 && r[0]=='$')
+		expandenv(&r, &n);
 	nt = t->w->tag.file->b.nc;
 	if(nt == 0)
 		goto Rescue;
-	if(n>=1 &&  r[0]=='/')
+	if(n>=1 && r[0]=='/')
 		goto Rescue;
 	b = runemalloc(nt+n+1);
 	bufread(&t->w->tag.file->b, 0, b, nt);
@@ -473,9 +477,12 @@ dirname(Text *t, Rune *r, int n)
 	}
 	if(slash < 0)
 		goto Rescue;
-	runemove(b+slash+1, r, n);
+	slash++;
+	if(expandenv(&b, &slash))
+		b = runerealloc(b, slash+n);
+	runemove(b+slash, r, n);
 	free(r);
-	return cleanrname(runestr(b, slash+1+n));
+	return cleanrname(runestr(b, slash+n));
 
     Rescue:
 	free(b);
@@ -535,9 +542,11 @@ expandfile(Text *t, uint q0, uint q1, Expand *e)
 	n = q1-q0;
 	if(n == 0)
 		return FALSE;
+
 	/* see if it's a file name */
-	r = runemalloc(n);
+	r = runemalloc(n+1);	/* +1 for $ below */
 	bufread(&t->file->b, q0, r, n);
+
 	/* first, does it have bad chars? */
 	nname = -1;
 	for(i=0; i<n; i++){
@@ -552,9 +561,13 @@ expandfile(Text *t, uint q0, uint q1, Expand *e)
 	}
 	if(nname == -1)
 		nname = n;
-	for(i=0; i<nname; i++)
+	for(i=0; i<nname; i++){
+		if(i==0 && r[0]=='$')
+			continue;
 		if(!isfilec(r[i]))
 			goto Isntfile;
+	}
+
 	/*
 	 * See if it's a file name in <>, and turn that into an include
 	 * file name if so.  Should probably do it for "" too, but that's not
@@ -569,10 +582,18 @@ expandfile(Text *t, uint q0, uint q1, Expand *e)
 	else if(amin == q0)
 		goto Isfile;
 	else{
-		rs = dirname(t, r, nname);
-		r = rs.r;
-		nname = rs.nr;
+		if(debug) fprint(2, "x1 %.*S\n", nname, r);
+		if(r[0] != '$'){
+			rs = dirname(t, r, nname);
+			r = rs.r;
+			nname = rs.nr;
+			if(debug) fprint(2, "x1.5 %.*S\n", nname, r);
+		}
+		if(r[0]=='$')
+			expandenv(&r, &nname);
+		if(debug) fprint(2, "x2 %.*S\n", nname, r);
 	}
+
 	e->bname = runetobyte(r, nname);
 	/* if it's already a window name, it's a file */
 	w = lookfile(r, nname);

src/cmd/acme/util.c

@@ -454,3 +454,4 @@ makenewwindow(Text *t)
 		colgrow(w->col, w, 1);
 	return w;
 }
+

src/cmd/acme/wind.c

@@ -258,6 +258,7 @@ winsetname(Window *w, Rune *name, int n)
 	int i;
 	static Rune Lslashguide[] = { '/', 'g', 'u', 'i', 'd', 'e', 0 };
 	static Rune Lpluserrors[] = { '+', 'E', 'r', 'r', 'o', 'r', 's', 0 };
+
 	t = &w->body;
 	if(runeeq(t->file->name, t->file->nname, name, n) == TRUE)
 		return;
@@ -318,8 +319,8 @@ wincleartag(Window *w)
 void
 winsettag1(Window *w)
 {
-	int i, j, k, n, bar, dirty;
-	Rune *new, *old, *r;
+	int i, j, k, n, ntagname, bar, dirty;
+	Rune *new, *old, *tagname, *r;
 	Image *b;
 	uint q0, q1;
 	Rectangle br;
@@ -331,6 +332,7 @@ winsettag1(Window *w)
 	static Rune Lput[] = { ' ', 'P', 'u', 't', 0 };
 	static Rune Llook[] = { ' ', 'L', 'o', 'o', 'k', ' ', 0 };
 	static Rune Lpipe[] = { ' ', '|', 0 };
+
 	/* there are races that get us here with stuff in the tag cache, so we take extra care to sync it */
 	if(w->tag.ncache!=0 || w->tag.file->mod)
 		wincommit(w, &w->tag);	/* check file name; also guarantees we can modify tag contents */
@@ -340,18 +342,27 @@ winsettag1(Window *w)
 	for(i=0; i<w->tag.file->b.nc; i++)
 		if(old[i]==' ' || old[i]=='\t')
 			break;
-	if(runeeq(old, i, w->body.file->name, w->body.file->nname) == FALSE){
+
+	/* make sure the file name is set correctly in the tag */
+	ntagname = w->body.file->nname;
+	tagname = runemalloc(ntagname);
+	runemove(tagname, w->body.file->name, ntagname);
+	abbrevenv(&tagname, &ntagname);
+
+	if(runeeq(old, i, tagname, ntagname) == FALSE){
 		textdelete(&w->tag, 0, i, TRUE);
-		textinsert(&w->tag, 0, w->body.file->name, w->body.file->nname, TRUE);
+		textinsert(&w->tag, 0, tagname, ntagname, TRUE);
 		free(old);
 		old = runemalloc(w->tag.file->b.nc+1);
 		bufread(&w->tag.file->b, 0, old, w->tag.file->b.nc);
 		old[w->tag.file->b.nc] = '\0';
 	}
-	new = runemalloc(w->body.file->nname+100);
+
+	/* compute the text for the whole tag, replacing current only if it differs */
+	new = runemalloc(ntagname+100);
 	i = 0;
-	runemove(new+i, w->body.file->name, w->body.file->nname);
-	i += w->body.file->nname;
+	runemove(new+i, tagname, ntagname);
+	i += ntagname;
 	runemove(new+i, Ldelsnarf, 10);
 	i += 10;
 	if(w->filemenu){
@@ -389,6 +400,8 @@ winsettag1(Window *w)
 	if(runestrlen(new) != i)
 		fprint(2, "s '%S' len not %d\n", new, i);
 	assert(i==runestrlen(new));
+
+	/* replace tag if the new one is different */
 	if(runeeq(new, i, old, k) == FALSE){
 		n = k;
 		if(n > i)
@@ -411,6 +424,7 @@ winsettag1(Window *w)
 			}
 		}
 	}
+	free(tagname);
 	free(old);
 	free(new);
 	w->tag.file->mod = FALSE;
@@ -463,6 +477,7 @@ wincommit(Window *w, Text *t)
 	for(i=0; i<w->tag.file->b.nc; i++)
 		if(r[i]==' ' || r[i]=='\t')
 			break;
+	expandenv(&r, &i);
 	if(runeeq(r, i, w->body.file->name, w->body.file->nname) == FALSE){
 		seq++;
 		filemark(w->body.file);
@@ -581,3 +596,153 @@ winevent(Window *w, char *fmt, ...)
 		sendp(x->c, nil);
 	}
 }
+
+int
+expandenv(Rune **rp, uint *np)
+{
+	char *s, *t;
+	Rune *p, *r, *q;
+	uint n, pref;
+	int nb, nr, slash;
+	Runestr rs;
+
+	r = *rp;
+	n = *np;
+	if(n == 0 || r[0] != '$')
+		return FALSE;
+	for(p=r+1; *p && *p != '/'; p++)
+		;
+	pref = p-r;
+	s = runetobyte(r+1, pref-1);
+	if((t = getenv(s)) == nil){
+		free(s);
+		return FALSE;
+	}
+
+	q = runemalloc(utflen(t)+(n-pref));
+	cvttorunes(t, strlen(t), q, &nb, &nr, nil);
+	assert(nr==utflen(t));
+	runemove(q+nr, p, n-pref);
+	free(r);
+	rs = runestr(q, nr+(n-pref));
+	slash = rs.nr>0 && q[rs.nr-1] == '/';
+	rs = cleanrname(rs);
+	if(slash){
+		rs.r = runerealloc(rs.r, rs.nr+1);
+		rs.r[rs.nr++] = '/';
+	}
+	*rp = rs.r;
+	*np = rs.nr;
+	return TRUE;
+}
+
+extern char **environ;
+Rune **runeenv;
+
+/*
+ * Weird sort order -- shorter names first, 
+ * prefer lowercase over uppercase ($home over $HOME),
+ * then do normal string comparison.
+ */
+int
+runeenvcmp(const void *va, const void *vb)
+{
+	Rune *a, *b;
+	int na, nb;
+
+	a = *(Rune**)va;
+	b = *(Rune**)vb;
+	na = runestrchr(a, '=') - a;
+	nb = runestrchr(b, '=') -  b;
+	if(na < nb)
+		return -1;
+	if(nb > na)
+		return 1;
+	if(na == 0)
+		return 0;
+	if(islowerrune(a[0]) && !islowerrune(b[0]))
+		return -1;
+	if(islowerrune(b[0]) && !islowerrune(a[0]))
+		return 1;
+	return runestrncmp(a, b, na);
+}
+
+void
+mkruneenv(void)
+{
+	int i, bad, n, nr;
+	char *p;
+	Rune *r, *q;
+
+	n = 0;
+	for(i=0; environ[i]; i++){
+		/*
+		 * Ignore some pollution.
+		 */
+		if(environ[i][0] == '_')
+			continue;
+		if(strncmp(environ[i], "PWD=", 4) == 0)
+			continue;
+		if(strncmp(environ[i], "OLDPWD=", 7) == 0)
+			continue;
+
+		/*
+		 * Must be a rooted path.
+		 */
+		if((p = strchr(environ[i], '=')) == nil || *(p+1) != '/')
+			continue;
+
+		/*
+		 * Only use the ones that we accept in look - all isfilec
+		 */
+		bad = 0;
+		r = bytetorune(environ[i], &nr);
+		for(q=r; *q != '='; q++)
+			if(!isfilec(*q)){
+				free(r);
+				bad = 1;
+				break;
+			}
+		if(!bad){
+			runeenv = erealloc(runeenv, (n+1)*sizeof(runeenv[0]));
+			runeenv[n++] = r;
+		}
+	}
+	runeenv = erealloc(runeenv, (n+1)*sizeof(runeenv[0]));
+	runeenv[n] = nil;
+	qsort(runeenv, n, sizeof(runeenv[0]), runeenvcmp);
+}
+
+int
+abbrevenv(Rune **rp, uint *np)
+{
+	int i, len, alen;
+	Rune *r, *p, *q;
+	uint n;
+
+	r = *rp;
+	n = *np;
+	if(n == 0 || r[0] != '/')
+		return FALSE;
+
+	if(runeenv == nil)
+		mkruneenv();
+
+	for(i=0; runeenv[i]; i++){
+		p = runestrchr(runeenv[i], '=')+1;
+		len = runestrlen(p);
+		if(len <= n && (r[len]==0 || r[len]=='/') && runeeq(r, len, p, len)==TRUE){
+			alen = (p-1) - runeenv[i];
+			q = runemalloc(1+alen+n-len);
+			q[0] = '$';
+			runemove(q+1, runeenv[i], alen);
+			runemove(q+1+alen, r+len, n-len);
+			free(r);
+			*rp = q;
+			*np = 1+alen+n-len;
+			return TRUE;
+		}
+	}
+	return FALSE;
+}
+