Implement flag for preserving whitespace around field (#1242)

man/man1/fzf.1

@@ -285,6 +285,9 @@ was made) individually quoted.
 e.g. \fBfzf --multi --preview='head -10 {+}'\fR
      \fBgit log --oneline | fzf --multi --preview 'git show {+1}'\fR
 
+When using a field index expression, leading and trailing whitespace is stripped
+from the replacement string. To preserve the whitespace, use the \fBs\fR flag.
+
 Also, \fB{q}\fR is replaced to the current query string.
 
 Note that you can escape a placeholder pattern by prepending a backslash.

src/terminal.go

@@ -24,7 +24,7 @@ import (
 var placeholder *regexp.Regexp
 
 func init() {
-	placeholder = regexp.MustCompile("\\\\?(?:{\\+?[0-9,-.]*}|{q})")
+	placeholder = regexp.MustCompile("\\\\?(?:{[+s]*[0-9,-.]*}|{q})")
 }
 
 type jumpMode int
@@ -221,6 +221,11 @@ const (
 	actTop
 )
 
+type placeholderFlags struct {
+	plus          bool
+	preserveSpace bool
+}
+
 func toActions(types ...actionType) []action {
 	actions := make([]action, len(types))
 	for idx, t := range types {
@@ -1130,12 +1135,37 @@ func quoteEntry(entry string) string {
 	return "'" + strings.Replace(entry, "'", "'\\''", -1) + "'"
 }
 
+func parsePlaceholder(match string) (bool, string, placeholderFlags) {
+	flags := placeholderFlags{}
+
+	if match[0] == '\\' {
+		// Escaped placeholder pattern
+		return true, match[1:], flags
+	}
+
+	skipChars := 1
+	for _, char := range match[1:] {
+		switch char {
+		case '+':
+			flags.plus = true
+			skipChars++
+		case 's':
+			flags.preserveSpace = true
+			skipChars++
+		default:
+			break
+		}
+	}
+
+	matchWithoutFlags := "{" + match[skipChars:]
+
+	return false, matchWithoutFlags, flags
+}
+
 func hasPlusFlag(template string) bool {
 	for _, match := range placeholder.FindAllString(template, -1) {
-		if match[0] == '\\' {
-			continue
-		}
-		if match[1] == '+' {
+		_, _, flags := parsePlaceholder(match)
+		if flags.plus {
 			return true
 		}
 	}
@@ -1152,9 +1182,10 @@ func replacePlaceholder(template string, stripAnsi bool, delimiter Delimiter, fo
 		selected = []*Item{}
 	}
 	return placeholder.ReplaceAllStringFunc(template, func(match string) string {
-		// Escaped pattern
-		if match[0] == '\\' {
-			return match[1:]
+		escaped, match, flags := parsePlaceholder(match)
+
+		if escaped {
+			return match
 		}
 
 		// Current query
@@ -1162,13 +1193,8 @@ func replacePlaceholder(template string, stripAnsi bool, delimiter Delimiter, fo
 			return quoteEntry(query)
 		}
 
-		plusFlag := forcePlus
-		if match[1] == '+' {
-			match = "{" + match[2:]
-			plusFlag = true
-		}
 		items := current
-		if plusFlag {
+		if flags.plus || forcePlus {
 			items = selected
 		}
 
@@ -1204,7 +1230,9 @@ func replacePlaceholder(template string, stripAnsi bool, delimiter Delimiter, fo
 					str = str[:delims[len(delims)-1][0]]
 				}
 			}
-			str = strings.TrimSpace(str)
+			if !flags.preserveSpace {
+				str = strings.TrimSpace(str)
+			}
 			replacements[idx] = quoteEntry(str)
 		}
 		return strings.Join(replacements, " ")

src/terminal_test.go

@@ -21,6 +21,9 @@ func TestReplacePlaceholder(t *testing.T) {
 		newItem("foo'bar \x1b[31mbaz\x1b[m"),
 		newItem("FOO'BAR \x1b[31mBAZ\x1b[m")}
 
+	delim := "'"
+	var regex *regexp.Regexp
+
 	var result string
 	check := func(expected string) {
 		if result != expected {
@@ -72,6 +75,31 @@ func TestReplacePlaceholder(t *testing.T) {
 	result = replacePlaceholder("echo {1}/{2}/{-1}/{-2}/{..}/{n.t}/\\{}/\\{1}/\\{q}/{3}", true, Delimiter{}, true, "query", items2)
 	check("echo 'foo'\\''bar' 'FOO'\\''BAR'/'baz' 'BAZ'/'baz' 'BAZ'/'foo'\\''bar' 'FOO'\\''BAR'/'foo'\\''bar baz' 'FOO'\\''BAR BAZ'/{n.t}/{}/{1}/{q}/'' ''")
 
+	// Whitespace preserving flag with "'" delimiter
+	result = replacePlaceholder("echo {s1}", true, Delimiter{str: &delim}, false, "query", items1)
+	check("echo '  foo'")
+
+	result = replacePlaceholder("echo {s2}", true, Delimiter{str: &delim}, false, "query", items1)
+	check("echo 'bar baz'")
+
+	result = replacePlaceholder("echo {s}", true, Delimiter{str: &delim}, false, "query", items1)
+	check("echo '  foo'\\''bar baz'")
+
+	result = replacePlaceholder("echo {s..}", true, Delimiter{str: &delim}, false, "query", items1)
+	check("echo '  foo'\\''bar baz'")
+
+	// Whitespace preserving flag with regex delimiter
+	regex = regexp.MustCompile("\\w+")
+
+	result = replacePlaceholder("echo {s1}", true, Delimiter{regex: regex}, false, "query", items1)
+	check("echo '  '")
+
+	result = replacePlaceholder("echo {s2}", true, Delimiter{regex: regex}, false, "query", items1)
+	check("echo ''\\'''")
+
+	result = replacePlaceholder("echo {s3}", true, Delimiter{regex: regex}, false, "query", items1)
+	check("echo ' '")
+
 	// No match
 	result = replacePlaceholder("echo {}/{+}", true, Delimiter{}, false, "query", []*Item{nil, nil})
 	check("echo /")
@@ -81,12 +109,11 @@ func TestReplacePlaceholder(t *testing.T) {
 	check("echo /'  foo'\\''bar baz'")
 
 	// String delimiter
-	delim := "'"
 	result = replacePlaceholder("echo {}/{1}/{2}", true, Delimiter{str: &delim}, false, "query", items1)
 	check("echo '  foo'\\''bar baz'/'foo'/'bar baz'")
 
 	// Regex delimiter
-	regex := regexp.MustCompile("[oa]+")
+	regex = regexp.MustCompile("[oa]+")
 	// foo'bar baz
 	result = replacePlaceholder("echo {}/{1}/{3}/{2..3}", true, Delimiter{regex: regex}, false, "query", items1)
 	check("echo '  foo'\\''bar baz'/'f'/'r b'/''\\''bar b'")