{Core} Add util function highlight_command

src/azure-cli-core/azure/cli/core/style.py

@@ -164,6 +164,40 @@ def format_styled_text(styled_text, theme=None):
     return ''.join(formatted_parts)
 
 
+def highlight_command(raw_command):
+    """Highlight a command to make it colored.
+
+    The highlighting rules after the command is splitted into args:
+        1. Args starting with '-' are regarded as parameter names, and they are with the ACTION style.
+        2. Args before the first parameter name are regarded as command name (or positional argument),
+        and they are with the ACTION style.
+        3. Args between the parameter names are regarded as parameter values, and they are with the PRIMARY style.
+        4. Args containing '=' are regarded as parameter name-value pairs, and they are with the PRIMARY style.
+
+    :param raw_command: The command that needs to be colored
+    :type raw_command: str
+    :return: The styled command text
+    :type: list
+    """
+
+    styled_command = []
+    argument_begins = False
+
+    for index, arg in enumerate(raw_command.split()):
+        spaced_arg = ' {}'.format(arg) if index > 0 else arg
+        style = Style.PRIMARY
+
+        if arg.startswith('-') and '=' not in arg:
+            style = Style.ACTION
+            argument_begins = True
+        elif not argument_begins and '=' not in arg:
+            style = Style.ACTION
+
+        styled_command.append((style, spaced_arg))
+
+    return styled_command
+
+
 def _is_modern_terminal():
     # Windows Terminal: https://github.com/microsoft/terminal/issues/1040
     if 'WT_SESSION' in os.environ:

src/azure-cli-core/azure/cli/core/tests/test_style.py

@@ -68,6 +68,42 @@ def test_format_styled_text_on_error(self):
         with self.assertRaisesRegex(CLIInternalError, "Invalid styled text."):
             format_styled_text(["dummy text"])
 
+    def test_highlight_command(self):
+        from azure.cli.core.style import Style, highlight_command, format_styled_text
+
+        raw_commands = [
+            'az cmd',
+            'az cmd sub-cmd',
+            'az cmd --arg val',
+            'az cmd --arg=val',
+            'az cmd --arg "content with space"',
+            'az cmd --arg val1 val2',
+            'az cmd sub-cmd --arg1 val1 --arg2=" " --arg3 "val2 val3" --arg4 val4'
+        ]
+
+        expected = [
+            [(Style.ACTION, 'az'), (Style.ACTION, ' cmd')],
+            [(Style.ACTION, 'az'), (Style.ACTION, ' cmd'), (Style.ACTION, ' sub-cmd')],
+            [(Style.ACTION, 'az'), (Style.ACTION, ' cmd'), (Style.ACTION, ' --arg'), (Style.PRIMARY, ' val')],
+            [(Style.ACTION, 'az'), (Style.ACTION, ' cmd'), (Style.PRIMARY, ' --arg=val')],
+            [(Style.ACTION, 'az'), (Style.ACTION, ' cmd'), (Style.ACTION, ' --arg'), (Style.PRIMARY, ' "content'),
+             (Style.PRIMARY, ' with'), (Style.PRIMARY, ' space"')],
+            [(Style.ACTION, 'az'), (Style.ACTION, ' cmd'), (Style.ACTION, ' --arg'),
+             (Style.PRIMARY, ' val1'), (Style.PRIMARY, ' val2')],
+            [(Style.ACTION, 'az'), (Style.ACTION, ' cmd'), (Style.ACTION, ' sub-cmd'), (Style.ACTION, ' --arg1'),
+             (Style.PRIMARY, ' val1'), (Style.PRIMARY, ' --arg2="'), (Style.PRIMARY, ' "'), (Style.ACTION, ' --arg3'),
+             (Style.PRIMARY, ' "val2'), (Style.PRIMARY, ' val3"'), (Style.ACTION, ' --arg4'), (Style.PRIMARY, ' val4')]
+        ]
+
+        for cmd_index, command in enumerate(raw_commands):
+            styled_command = highlight_command(command)
+            expected_style = expected[cmd_index]
+
+            for tpl_index, style_tuple in enumerate(styled_command):
+                expected_tuple = expected_style[tpl_index]
+                self.assertEqual(style_tuple[0], expected_tuple[0])
+                self.assertEqual(style_tuple[1], expected_tuple[1])
+
     def test_format_styled_text_theme(self):
         from azure.cli.core.style import Style, format_styled_text
         styled_text = [