Nullify --nth option when it's irrelevant

3 files changed, 62 insertions, 11 deletions

diff --git a/src/options.go b/src/options.go
index e1dba299..b11328e5 100644
--- a/src/options.go
+++ b/src/options.go
@@ -266,6 +266,17 @@ func parseOptions(opts *Options, allArgs []string) {
 			}
 		}
 	}
+
+	// If we're not using extended search mode, --nth option becomes irrelevant
+	// if it contains the whole range
+	if opts.Mode == ModeFuzzy || len(opts.Nth) == 1 {
+		for _, r := range opts.Nth {
+			if r.begin == rangeEllipsis && r.end == rangeEllipsis {
+				opts.Nth = make([]Range, 0)
+				return
+			}
+		}
+	}
 }
 
 // ParseOptions parses command-line options
diff --git a/src/options_test.go b/src/options_test.go
index e10ec569..782ad791 100644
--- a/src/options_test.go
+++ b/src/options_test.go
@@ -21,17 +21,47 @@ func TestSplitNth(t *testing.T) {
 		}
 	}
 	{
-		ranges := splitNth("..3,1..,2..3,4..-1,-3..-2,..,2,-2")
-		if len(ranges) != 8 ||
+		ranges := splitNth("..3,1..,2..3,4..-1,-3..-2,..,2,-2,2..-2,1..-1")
+		if len(ranges) != 10 ||
 			ranges[0].begin != rangeEllipsis || ranges[0].end != 3 ||
-			ranges[1].begin != 1 || ranges[1].end != rangeEllipsis ||
+			ranges[1].begin != rangeEllipsis || ranges[1].end != rangeEllipsis ||
 			ranges[2].begin != 2 || ranges[2].end != 3 ||
-			ranges[3].begin != 4 || ranges[3].end != -1 ||
+			ranges[3].begin != 4 || ranges[3].end != rangeEllipsis ||
 			ranges[4].begin != -3 || ranges[4].end != -2 ||
 			ranges[5].begin != rangeEllipsis || ranges[5].end != rangeEllipsis ||
 			ranges[6].begin != 2 || ranges[6].end != 2 ||
-			ranges[7].begin != -2 || ranges[7].end != -2 {
+			ranges[7].begin != -2 || ranges[7].end != -2 ||
+			ranges[8].begin != 2 || ranges[8].end != -2 ||
+			ranges[9].begin != rangeEllipsis || ranges[9].end != rangeEllipsis {
 			t.Errorf("%s", ranges)
 		}
 	}
 }
+
+func TestIrrelevantNth(t *testing.T) {
+	{
+		opts := defaultOptions()
+		words := []string{"--nth", "..", "-x"}
+		parseOptions(opts, words)
+		if len(opts.Nth) != 0 {
+			t.Errorf("nth should be empty: %s", opts.Nth)
+		}
+	}
+	for _, words := range [][]string{[]string{"--nth", "..,3"}, []string{"--nth", "3,1.."}, []string{"--nth", "..-1,1"}} {
+		{
+			opts := defaultOptions()
+			parseOptions(opts, words)
+			if len(opts.Nth) != 0 {
+				t.Errorf("nth should be empty: %s", opts.Nth)
+			}
+		}
+		{
+			opts := defaultOptions()
+			words = append(words, "-x")
+			parseOptions(opts, words)
+			if len(opts.Nth) != 2 {
+				t.Errorf("nth should not be empty: %s", opts.Nth)
+			}
+		}
+	}
+}
diff --git a/src/tokenizer.go b/src/tokenizer.go
index 26aebd94..d38f46f5 100644
--- a/src/tokenizer.go
+++ b/src/tokenizer.go
@@ -28,22 +28,32 @@ type Token struct {
 	prefixLength int
 }
 
+func newRange(begin int, end int) Range {
+	if begin == 1 {
+		begin = rangeEllipsis
+	}
+	if end == -1 {
+		end = rangeEllipsis
+	}
+	return Range{begin, end}
+}
+
 // ParseRange parses nth-expression and returns the corresponding Range object
 func ParseRange(str *string) (Range, bool) {
 	if (*str) == ".." {
-		return Range{rangeEllipsis, rangeEllipsis}, true
+		return newRange(rangeEllipsis, rangeEllipsis), true
 	} else if strings.HasPrefix(*str, "..") {
 		end, err := strconv.Atoi((*str)[2:])
 		if err != nil || end == 0 {
 			return Range{}, false
 		}
-		return Range{rangeEllipsis, end}, true
+		return newRange(rangeEllipsis, end), true
 	} else if strings.HasSuffix(*str, "..") {
 		begin, err := strconv.Atoi((*str)[:len(*str)-2])
 		if err != nil || begin == 0 {
 			return Range{}, false
 		}
-		return Range{begin, rangeEllipsis}, true
+		return newRange(begin, rangeEllipsis), true
 	} else if strings.Contains(*str, "..") {
 		ns := strings.Split(*str, "..")
 		if len(ns) != 2 {
@@ -51,17 +61,17 @@ func ParseRange(str *string) (Range, bool) {
 		}
 		begin, err1 := strconv.Atoi(ns[0])
 		end, err2 := strconv.Atoi(ns[1])
-		if err1 != nil || err2 != nil {
+		if err1 != nil || err2 != nil || begin == 0 || end == 0 {
 			return Range{}, false
 		}
-		return Range{begin, end}, true
+		return newRange(begin, end), true
 	}
 
 	n, err := strconv.Atoi(*str)
 	if err != nil || n == 0 {
 		return Range{}, false
 	}
-	return Range{n, n}, true
+	return newRange(n, n), true
 }
 
 func withPrefixLengths(tokens []string, begin int) []Token {