=== modified file 'data.awk'
--- data.awk	2015-09-23 01:42:51 +0000
+++ data.awk	2015-09-17 07:09:55 +0000
@@ -56,7 +56,7 @@
 	m = match($0, ident_re)
 	varname = substr($0, m, RLENGTH)
 	V[varname] = substr($0, m+1+RLENGTH)
-	if(DEBUG) printf "got scalar: %s = %s (%d)\n", varname, V[varname], m >"/dev/stderr"
+	if(DEBUG) printf "got scalar: %s ⇒ %s (%d)\n", varname, V[varname], m >"/dev/stderr"
 	next
 }
 
@@ -102,44 +102,32 @@
 				continue
 		loopvar = loop_stack[i, "var"]
 		looprow = loop_stack[i, "row"]
-		if(varname == prefix"_index") {
-			found = looprow
-			return 1
-		}
-		if(varname == prefix"_index0") {
-			found = looprow - 1
-			return 1
-		}
-		if(varname == prefix"_revindex") {
-			found = V[loopvar, "rows"] - looprow + 1
-			return 1
-		}
-		if(varname == prefix"_revindex0") {
-			found = V[loopvar, "rows"] - looprow
-			return 1
-		}
-		if(varname == prefix"_first") {
-			found = looprow == 1
-			return 1
-		}
-		if(varname == prefix"_last") {
-			found = looprow == V[loopvar, "rows"]
-			return 1
-		}
-		if(varname == prefix"_length") {
-			found = V[loopvar, "rows"]
-			return 1
-		}
+		if(varname == prefix"_index")
+			return looprow
+		if(varname == prefix"_index0")
+			return looprow - 1
+		if(varname == prefix"_revindex")
+			return V[loopvar, "rows"] - looprow + 1
+		if(varname == prefix"_revindex0")
+			return V[loopvar, "rows"] - looprow
+		if(varname == prefix"_first")
+			return looprow == 1
+		if(varname == prefix"_last")
+			return looprow == V[loopvar, "rows"]
+		if(varname == prefix"_length")
+			return V[loopvar, "rows"]
 		split(V[loopvar, "fields"], names)
 		for(n in names) {
 			if(varname == (prefix names[n])) {
 				split(V[loopvar, looprow], values)
-				found = values[n]
-				return 1
+				return values[n]
 			}
 		}
 	}
 	if(!(varname in V)) {
+		if(DEBUG) {
+			print "variable not found: " varname >"/dev/stderr"
+		}
 		return 0
 	}
 	found = V[varname]
@@ -149,14 +137,10 @@
 function get(varname) {
 	if(!find(varname)) {
 		if(ENVIRON["DATA_AWK_EMPTY_GET"]) {
-			if(DEBUG) {
-				print "variable not found: " varname >"/dev/stderr"
-			}
-			found = ""
-		} else {
-			print "error: undefined variable '"varname"'" >"/dev/stderr"
-			exit 1
+			return ""
 		}
+		print "error: undefined variable '"varname"'" >"/dev/stderr"
+		exit 1
 	}
 	if(DEBUG) {
 		print "get →" varname "← = →"found"←" >"/dev/stderr"
@@ -171,10 +155,9 @@
 END {
 	if(DEBUG) {
 		print "--- loaded keys ---" >"/dev/stderr"
-		for(key in V) {
-			printf("%s\t→%s←\n", key, V[key]) >"/dev/stderr"
+		for(key in V)
+			printf("%s\t→%s←\t", key, V[key]) >"/dev/stderr"
 			printf(">> %d →%s←\n", find(key), found) >"/dev/stderr"
-		}
 		print "-------------------" >"/dev/stderr"
 	}
 }