lib/encoder: add LeftPeriod encoding

fstest/fstests/fstests.go

@@ -554,6 +554,7 @@ func Run(t *testing.T, opt *Opt) {
 				{"leading LF", "\nleading LF"},
 				{"leading HT", "\tleading HT"},
 				{"leading VT", "\vleading VT"},
+				{"leading dot", ".leading dot"},
 				{"trailing space", "trailing space "},
 				{"trailing CR", "trailing CR\r"},
 				{"trailing LF", "trailing LF\n"},

lib/encoder/encoder.go

@@ -53,6 +53,7 @@ const (
 	EncodeDel                            // DEL(0x7F)
 	EncodeCtl                            // CTRL(0x01-0x1F)
 	EncodeLeftSpace                      // Leading SPACE
+	EncodeLeftPeriod                     // Leading .
 	EncodeLeftTilde                      // Leading ~
 	EncodeLeftCrLfHtVt                   // Leading CR LF HT VT
 	EncodeRightSpace                     // Trailing SPACE
@@ -127,6 +128,13 @@ func (mask MultiEncoder) Encode(in string) string {
 			prefix, in = string(QuoteRune)+"␠", in[l:] // SYMBOL FOR SPACE
 		}
 	}
+	if mask.Has(EncodeLeftPeriod) && prefix == "" { // Leading PERIOD
+		if in[0] == '.' {
+			prefix, in = "．", in[1:] // FULLWIDTH FULL STOP
+		} else if r, l := utf8.DecodeRuneInString(in); r == '．' { // FULLWIDTH FULL STOP
+			prefix, in = string(QuoteRune)+"．", in[l:] //  FULLWIDTH FULL STOP
+		}
+	}
 	if mask.Has(EncodeLeftTilde) && prefix == "" { // Leading ~
 		if in[0] == '~' {
 			prefix, in = string('~'+fullOffset), in[1:] // FULLWIDTH TILDE
@@ -533,6 +541,8 @@ func (mask MultiEncoder) Decode(in string) string {
 	prefix := ""
 	if r, l1 := utf8.DecodeRuneInString(in); mask.Has(EncodeLeftSpace) && r == '␠' { // SYMBOL FOR SPACE
 		prefix, in = " ", in[l1:]
+	} else if mask.Has(EncodeLeftPeriod) && r == '．' { // FULLWIDTH FULL STOP
+		prefix, in = ".", in[l1:]
 	} else if mask.Has(EncodeLeftTilde) && r == '～' { // FULLWIDTH TILDE
 		prefix, in = "~", in[l1:]
 	} else if mask.Has(EncodeLeftCrLfHtVt) && (r == '␀'+'\t' || r == '␀'+'\n' || r == '␀'+'\v' || r == '␀'+'\r') {
@@ -540,6 +550,8 @@ func (mask MultiEncoder) Decode(in string) string {
 	} else if r == QuoteRune {
 		if r, l2 := utf8.DecodeRuneInString(in[l1:]); mask.Has(EncodeLeftSpace) && r == '␠' { // SYMBOL FOR SPACE
 			prefix, in = "␠", in[l1+l2:]
+		} else if mask.Has(EncodeLeftPeriod) && r == '．' { // FULLWIDTH FULL STOP
+			prefix, in = "．", in[l1+l2:]
 		} else if mask.Has(EncodeLeftTilde) && r == '～' { // FULLWIDTH TILDE
 			prefix, in = "～", in[l1+l2:]
 		} else if mask.Has(EncodeLeftCrLfHtVt) && (r == '␀'+'\t' || r == '␀'+'\n' || r == '␀'+'\v' || r == '␀'+'\r') {

lib/encoder/internal/gen/main.go

@@ -57,6 +57,7 @@ var maskBits = []struct {
 	{encoder.EncodeDel, "EncodeDel"},
 	{encoder.EncodeCtl, "EncodeCtl"},
 	{encoder.EncodeLeftSpace, "EncodeLeftSpace"},
+	{encoder.EncodeLeftPeriod, "EncodeLeftPeriod"},
 	{encoder.EncodeLeftTilde, "EncodeLeftTilde"},
 	{encoder.EncodeLeftCrLfHtVt, "EncodeLeftCrLfHtVt"},
 	{encoder.EncodeRightSpace, "EncodeRightSpace"},
@@ -76,6 +77,7 @@ type edge struct {
 
 var allEdges = []edge{
 	{encoder.EncodeLeftSpace, "EncodeLeftSpace", edgeLeft, []rune{' '}, []rune{'␠'}},
+	{encoder.EncodeLeftPeriod, "EncodeLeftPeriod", edgeLeft, []rune{'.'}, []rune{'．'}},
 	{encoder.EncodeLeftTilde, "EncodeLeftTilde", edgeLeft, []rune{'~'}, []rune{'～'}},
 	{encoder.EncodeLeftCrLfHtVt, "EncodeLeftCrLfHtVt", edgeLeft,
 		[]rune{'\t', '\n', '\v', '\r'},
@@ -311,6 +313,10 @@ var testCasesSingleEdge = []testCase{
 		mask: EncodeLeftSpace,
 		in:   "  ",
 		out:  "␠ ",
+	}, { // %d
+		mask: EncodeLeftPeriod,
+		in:   "..",
+		out:  "．.",
 	}, { // %d
 		mask: EncodeLeftTilde,
 		in:   "~~",
@@ -339,6 +345,10 @@ var testCasesSingleEdge = []testCase{
 		mask: EncodeLeftSpace | EncodeRightSpace,
 		in:   "   ",
 		out:  "␠ ␠",
+	}, { // %d
+		mask: EncodeLeftPeriod | EncodeRightPeriod,
+		in:   "...",
+		out:  "．.．",
 	}, { // %d
 		mask: EncodeRightPeriod | EncodeRightSpace,
 		in:   "a. ",
@@ -351,7 +361,7 @@ var testCasesSingleEdge = []testCase{
 }
 
 var testCasesDoubleEdge = []testCase{
-	`, i(), i(), i(), i(), i(), i(), i(), i(), i(), i()))("Error writing test case:")
+	`, i(), i(), i(), i(), i(), i(), i(), i(), i(), i(), i(), i()))("Error writing test case:")
 	_i = 0
 	for _, e1 := range allEdges {
 		for _, e2 := range allEdges {