Tweak .build-dir widget and only enable during build-dir

build/build.plugin.zsh

@@ -194,6 +194,10 @@ EOF
   if [[ -n $do_build ]]; then
     eval build
   fi
+
+  # Bind C-B to fuzzy find & complete cmake variables.
+  zle -N .build-var
+  bindkey '^B' .build-var
 }
 
 # Build then run a target residing in `~build/bin`.
@@ -210,9 +214,6 @@ build-debug() {
 
 # Fuzzy find CMake variables, select one to set the variable via a command.
 .build-var() {
-  if [[ ! -n $build_dir ]]; then
-    build-dir
-  fi
   local var=$(
     cat $build_dir/CMakeCache.txt |
     grep --color=never -Ex '^\w+:\w+=.*$' |
@@ -220,10 +221,12 @@ build-debug() {
         --cycle --height=50%
   )
   if [[ -n "$var" ]]; then
+    if [[ "$BUFFER" = "cmake"* ]]; then
+      BUFFER="$BUFFER-D$var"
+    else
       BUFFER="cmake -B\$build_dir -D$var"
+    fi
     zle end-of-line
   fi
   zle reset-prompt
 }
-zle -N .build-var
-bindkey '^B' .build-var