[CLI] Add example command to CLI

docs/utilities.rst

@@ -62,7 +62,7 @@ The suggested workflow for the performance related PR author to run the regressi
 * Run ``git checkout -b your-branch-name``.
 
 * Do works on the issue, stage 1.
-  
+
 * Run ``ti benchmark && ti regression`` to obtain the result.
 
 * (If result BAD) Do further improvements, until the result is satisfying.

python/build.py

@@ -64,6 +64,7 @@ def get_python_executable():
 
 shutil.rmtree('taichi/lib', ignore_errors=True)
 shutil.rmtree('taichi/tests', ignore_errors=True)
+shutil.rmtree('taichi/examples', ignore_errors=True)
 os.makedirs('taichi/lib', exist_ok=True)
 shutil.rmtree('build', ignore_errors=True)
 shutil.rmtree('dist', ignore_errors=True)
@@ -80,6 +81,7 @@ def get_python_executable():
                 'taichi/lib/taichi_core.pyd')
 
 shutil.copytree('../tests/python', './taichi/tests')
+shutil.copytree('../examples', './taichi/examples')
 
 if get_os_name() != 'osx':
     libdevice_path = ti.core.libdevice_path()
@@ -106,6 +108,7 @@ def get_python_executable():
 
 shutil.rmtree('taichi/lib')
 shutil.rmtree('taichi/tests')
+shutil.rmtree('taichi/examples')
 shutil.rmtree('./build')
 
 if mode == 'upload':

python/taichi/main.py

@@ -8,6 +8,7 @@
 from collections import defaultdict
 from colorama import Fore, Back, Style
 from taichi.tools.video import make_video, interpolate_frames, mp4_to_gif, scale_video, crop_video, accelerate_video
+import importlib
 
 
 def test_python(args):
@@ -72,6 +73,31 @@ def test_cpp(args):
     return int(task.run(*test_files))
 
 
+def run_example(name: list):
+    """Run an example based on the example NAME."""
+    import taichi as ti
+    from pathlib import Path
+
+    root_dir = ti.package_root() if ti.is_release() else ti.get_repo_directory(
+    )
+    examples_dir = Path(root_dir) / 'examples'
+    all_examples = examples_dir.rglob('*.py')
+    all_example_names = {
+        str(f.resolve()).split('/')[-1].split('.')[0]
+        for f in all_examples
+    }
+    if len(name) != 1:
+        sys.exit(
+            f"Sorry, please specify a name of example!\nAvailable examples names are: {all_example_names}"
+        )
+    elif name[0] not in all_example_names:
+        sys.exit(
+            f"Sorry, {name} is not an available example name!\nAvailable examples names are: {all_example_names}"
+        )
+    print(f"Running example {name[0]} ...")
+    importlib.import_module(f"examples.{name[0]}")
+
+
 def get_benchmark_baseline_dir():
     import taichi as ti
     return os.path.join(ti.core.get_repo_dir(), 'benchmarks', 'baseline')
@@ -86,8 +112,10 @@ def display_benchmark_regression(xd, yd, args):
     def parse_dat(file):
         dict = {}
         for line in open(file).readlines():
-            try: a, b = line.strip().split(':')
-            except: continue
+            try:
+                a, b = line.strip().split(':')
+            except:
+                continue
             b = float(b)
             if abs(b % 1.0) < 1e-5:  # codegen_*
                 b = int(b)
@@ -120,7 +148,8 @@ def plot_in_gui(scatter):
         gui = ti.GUI('Regression Test', (640, 480), 0x001122)
         print('[Hint] press SPACE to go for next display')
         for key, data in scatter.items():
-            data = np.array([((i + 0.5)/len(data), x/2) for i, x in enumerate(data)])
+            data = np.array([((i + 0.5) / len(data), x / 2)
+                             for i, x in enumerate(data)])
             while not gui.get_event((ti.GUI.PRESS, ti.GUI.SPACE)):
                 gui.core.title = key
                 gui.line((0, 0.5), (1, 0.5), 1.8, 0x66ccff)
@@ -183,7 +212,9 @@ def make_argument_parser():
                         '--verbose',
                         action='store_true',
                         help='Run with verbose outputs')
-    parser.add_argument('-r', '--rerun', help='Rerun failed tests for given times')
+    parser.add_argument('-r',
+                        '--rerun',
+                        help='Rerun failed tests for given times')
     parser.add_argument('-t',
                         '--threads',
                         help='Number of threads for parallel testing')
@@ -263,7 +294,9 @@ def main(debug=False):
             "           ti gif                    |-> Convert mp4 file to gif\n"
             "           ti doc                    |-> Build documentation\n"
             "           ti release                |-> Make source code release\n"
-            "           ti debug [script.py]      |-> Debug script\n")
+            "           ti debug [script.py]      |-> Debug script\n"
+            "           ti example [name]         |-> Run an example by name\n"
+        )
         return 0
 
     t = time.time()
@@ -407,6 +440,7 @@ def main(debug=False):
         framerate = 24
         mp4_to_gif(input_fn, output_fn, framerate)
     elif mode == "convert":
+        import shutil
         # http://www.commandlinefu.com/commands/view/3584/remove-color-codes-special-characters-with-sed
         # TODO: Windows support
         for fn in sys.argv[2:]:
@@ -438,6 +472,9 @@ def main(debug=False):
         fn = f'taichi-src-v{ver[0]}-{ver[1]}-{ver[2]}-{commit}-{md5}.zip'
         import shutil
         shutil.move('release.zip', fn)
+    elif mode == "example":
+        example = sys.argv[2:]
+        run_example(name=example)
     else:
         name = sys.argv[1]
         print('Running task [{}]...'.format(name))