Changes needed in order to implement Compass back to Yeoman's generator-webapp.

generator-webapp-with-compass.diff

-sass: {
-  files: ['<%= config.app %>/styles/{,*/}*.{scss,sass}'],
-  tasks: ['sass:server', 'autoprefixer']
-}
+compass: {
+  files: ['<%= config.app %>/styles/{,*/}*.{scss,sass}'],
+  tasks: ['compass:server', 'autoprefixer']
+}

...

-sass: {
-  dist: {
-    files: [{
-      expand: true,
-      cwd: '<%= config.app %>/styles',
-      src: ['*.scss'],
-      dest: '.tmp/styles',
-      ext: '.css'
-    }]
-  },
-  server: {
-    files: [{
-      expand: true,
-      cwd: '<%= config.app %>/styles',
-      src: ['*.scss'],
-      dest: '.tmp/styles',
-      ext: '.css'
-    }]
-  }
-}
+compass: {
+  options: {
+    sassDir: '<%= config.app %>/styles',
+    cssDir: '.tmp/styles',
+    generatedImagesDir: '.tmp/images/generated',
+    imagesDir: '<%= config.app %>/images',
+    javascriptsDir: '<%= config.app %>/scripts',
+    fontsDir: '<%= config.app %>/styles/fonts',
+    importPath: './bower_components',
+    httpImagesPath: '/images',
+    httpGeneratedImagesPath: '/images/generated',
+    httpFontsPath: '/styles/fonts',
+    relativeAssets: false,
+    assetCacheBuster: false
+  },
+  dist: {
+    options: {
+      generatedImagesDir: '<%= config.dist %>/images/generated'
+    }
+  },
+  server: {
+    options: {
+      debugInfo: true
+    }
+  }
+}

...

 concurrent: {
   server: [
-    'sass:server',
+    'compass:server',
     'coffee:dist',
     'copy:styles'
   ],
   test: [
     'coffee',
     'copy:styles'
   ],
   dist: [
     'coffee',
-    'sass',
+    'compass',
     'copy:styles',
     'imagemin',
     'svgmin'
   ]
 }

one comma is missing at line #51

@fusionstrings thanks!