steveej-laptop/system: rework PS1

configuration/steveej-laptop/system.nix

@@ -30,21 +30,36 @@
   programs.bash = {
     enableCompletion = true;
     promptInit = ''
-          if test "$TERM" != "dumb"; then
-            # Provide a nice prompt.
-            BLUE="\[\033[0;34m\]"
-            RED="\[\033[1;31m\]"
-            GREEN="\[\033[1;32m\]"
-            NO_COLOR="\[\033[0m\]"
+      function exitstatus() {
+        if [[ $? -eq 0 ]]; then
+          printf '✓'
+        else
+          printf '✗'
+        fi
+      }
+      function nixshellEval {
+        if [[ "$1" != "" ]]; then
+          printf "»$1« "
+        fi
+      }
+      function setPS1 {
+        if test "$TERM" != "dumb"; then
+          # Provide a nice prompt.
+          BLUE="\[\033[0;34m\]"
+          RED="\[\033[1;31m\]"
+          GREEN="\[\033[1;32m\]"
+          NO_COLOR="\[\033[0m\]"
 
-            PROMPT_COLOR=$RED
-            let $UID && PROMPT_COLOR=$GREEN
-            PS1=" $BLUE\W/ $PROMPT_COLOR\\$ $NO_COLOR"
-            if test "$TERM" = "xterm"; then
-              PS1="\[\033]2;\h:\u:\w\007\]$PS1"
-            fi
+          PROMPT_COLOR=$RED
+          let $UID && PROMPT_COLOR=$GREEN
+          PS1="$PROMPT_COLOR\u$NO_COLOR@\h \$(exitstatus) \$(nixshellEval $1)$BLUE\w$NO_COLOR\n$PROMPT_COLOR\\$ $NO_COLOR"
+          if test "$TERM" = "xterm"; then
+            PS1="\[\033]2;\h:\u:\w\007\]$PS1"
           fi
-        '';
+        fi
+      }
+      setPS1
+    '';
   };
 
    # Package configuration