config,terminal: Add source-list-line-color configuration option

This change adds a config flag to specify the foreground color of
line numbers for the source list command.

pkg/config/config.go

@@ -43,6 +43,10 @@ type Config struct {
 	// If ShowLocationExpr is true whatis will print the DWARF location
 	// expression for its argument.
 	ShowLocationExpr bool `yaml:"show-location-expr"`
+	
+	// Source list line-number color (3/4 bit color codes as defined
+	// here: https://en.wikipedia.org/wiki/ANSI_escape_code#Colors)
+	SourceListLineColor int `yaml:"source-list-line-color"`
 }
 
 // LoadConfig attempts to populate a Config object from the config.yml file.
@@ -129,6 +133,11 @@ func writeDefaultConfig(f *os.File) error {
 # This is the default configuration file. Available options are provided, but disabled.
 # Delete the leading hash mark to enable an item.
 
+# Uncomment the following line and set your preferred ANSI foreground color
+# for source line numbers in the (list) command (if unset, default is 34,
+# dark blue) See https://en.wikipedia.org/wiki/ANSI_escape_code#3/4_bit
+# source-list-line-color: 34
+
 # Provided aliases will be added to the default aliases for a given command.
 aliases:
   # command: ["alias1", "alias2"]

pkg/terminal/terminal.go

@@ -19,9 +19,28 @@ import (
 )
 
 const (
-	historyFile             string = ".dbg_history"
-	terminalBlueEscapeCode  string = "\033[34m"
-	terminalResetEscapeCode string = "\033[0m"
+	historyFile                 string = ".dbg_history"
+	terminalHighlightEscapeCode string = "\033[%2dm"
+	terminalResetEscapeCode     string = "\033[0m"
+)
+
+const (
+	ansiBlack     = 30
+	ansiRed       = 31
+	ansiGreen     = 32
+	ansiYellow    = 33
+	ansiBlue      = 34
+	ansiMagenta   = 35
+	ansiCyan      = 36
+	ansiWhite     = 37
+	ansiBrBlack   = 90
+	ansiBrRed     = 91
+	ansiBrGreen   = 92
+	ansiBrYellow  = 93
+	ansiBrBlue    = 94
+	ansiBrMagenta = 95
+	ansiBrCyan    = 96
+	ansiBrWhite   = 97
 )
 
 // Term represents the terminal running dlv.
@@ -81,6 +100,13 @@ func New(client service.Client, conf *config.Config) *Term {
 		client.SetReturnValuesLoadConfig(&LongLoadConfig)
 	}
 
+	if (conf.SourceListLineColor > ansiWhite &&
+		conf.SourceListLineColor < ansiBrBlack) ||
+		conf.SourceListLineColor < ansiBlack ||
+		conf.SourceListLineColor > ansiBrWhite {
+		conf.SourceListLineColor = ansiBlue
+	}
+
 	return &Term{
 		client: client,
 		conf:   conf,
@@ -217,7 +243,8 @@ func (t *Term) Run() (int, error) {
 // Println prints a line to the terminal.
 func (t *Term) Println(prefix, str string) {
 	if !t.dumb {
-		prefix = fmt.Sprintf("%s%s%s", terminalBlueEscapeCode, prefix, terminalResetEscapeCode)
+		terminalColorEscapeCode := fmt.Sprintf(terminalHighlightEscapeCode, t.conf.SourceListLineColor)
+		prefix = fmt.Sprintf("%s%s%s", terminalColorEscapeCode, prefix, terminalResetEscapeCode)
 	}
 	fmt.Fprintf(t.stdout, "%s%s\n", prefix, str)
 }