refactor: simplify OrderedDict arguments in lexer (#598)

plamut · web-flow · commit c741c381c224 · 2021-04-13T18:50:05.000+02:00
Python 3.6+ guarantees that kwargs order is preserved, thus we
don't need to assure the order by passing them as a list of tuples.
diff --git a/google/cloud/bigquery/magics/line_arg_parser/lexer.py b/google/cloud/bigquery/magics/line_arg_parser/lexer.py
@@ -49,90 +49,45 @@
 # the value of an option other than "--params", we do not really care about its
 # structure, and thus do not want to use any of the "Python tokens" for pattern matching.
 #
-# Since token definition order is important, an OrderedDict is needed with tightly
-# controlled member definitions (i.e. passed as a sequence, and *not* via kwargs).
+# Token definition order is important, thus an OrderedDict is used. In addition, PEP 468
+# guarantees us that the order of kwargs is preserved in Python 3.6+.
 token_types = OrderedDict(
-    [
-        (
-            "state_parse_pos_args",
-            OrderedDict(
-                [
-                    (
-                        "GOTO_PARSE_NON_PARAMS_OPTIONS",
-                        r"(?P<GOTO_PARSE_NON_PARAMS_OPTIONS>(?=--))",  # double dash - starting the options list
-                    ),
-                    (
-                        "DEST_VAR",
-                        r"(?P<DEST_VAR>[^\d\W]\w*)",  # essentially a Python ID
-                    ),
-                ]
-            ),
-        ),
-        (
-            "state_parse_non_params_options",
-            OrderedDict(
-                [
-                    (
-                        "GOTO_PARSE_PARAMS_OPTION",
-                        r"(?P<GOTO_PARSE_PARAMS_OPTION>(?=--params(?:\s|=|--|$)))",  # the --params option
-                    ),
-                    ("OPTION_SPEC", r"(?P<OPTION_SPEC>--\w+)"),
-                    ("OPTION_EQ", r"(?P<OPTION_EQ>=)"),
-                    ("OPT_VAL", r"(?P<OPT_VAL>\S+?(?=\s|--|$))"),
-                ]
-            ),
-        ),
-        (
-            "state_parse_params_option",
-            OrderedDict(
-                [
-                    (
-                        "PY_STRING",
-                        r"(?P<PY_STRING>(?:{})|(?:{}))".format(
-                            r"'(?:[^'\\]|\.)*'",
-                            r'"(?:[^"\\]|\.)*"',  # single and double quoted strings
-                        ),
-                    ),
-                    ("PARAMS_OPT_SPEC", r"(?P<PARAMS_OPT_SPEC>--params(?=\s|=|--|$))"),
-                    ("PARAMS_OPT_EQ", r"(?P<PARAMS_OPT_EQ>=)"),
-                    (
-                        "GOTO_PARSE_NON_PARAMS_OPTIONS",
-                        r"(?P<GOTO_PARSE_NON_PARAMS_OPTIONS>(?=--\w+))",  # found another option spec
-                    ),
-                    ("PY_BOOL", r"(?P<PY_BOOL>True|False)"),
-                    ("DOLLAR_PY_ID", r"(?P<DOLLAR_PY_ID>\$[^\d\W]\w*)"),
-                    (
-                        "PY_NUMBER",
-                        r"(?P<PY_NUMBER>-?[1-9]\d*(?:\.\d+)?(:?[e|E][+-]?\d+)?)",
-                    ),
-                    ("SQUOTE", r"(?P<SQUOTE>')"),
-                    ("DQUOTE", r'(?P<DQUOTE>")'),
-                    ("COLON", r"(?P<COLON>:)"),
-                    ("COMMA", r"(?P<COMMA>,)"),
-                    ("LCURL", r"(?P<LCURL>\{)"),
-                    ("RCURL", r"(?P<RCURL>})"),
-                    ("LSQUARE", r"(?P<LSQUARE>\[)"),
-                    ("RSQUARE", r"(?P<RSQUARE>])"),
-                    ("LPAREN", r"(?P<LPAREN>\()"),
-                    ("RPAREN", r"(?P<RPAREN>\))"),
-                ]
-            ),
-        ),
-        (
-            "common",
-            OrderedDict(
-                [
-                    ("WS", r"(?P<WS>\s+)"),
-                    ("EOL", r"(?P<EOL>$)"),
-                    (
-                        # anything not a whitespace or matched by something else
-                        "UNKNOWN",
-                        r"(?P<UNKNOWN>\S+)",
-                    ),
-                ]
-            ),
+    state_parse_pos_args=OrderedDict(
+        GOTO_PARSE_NON_PARAMS_OPTIONS=r"(?P<GOTO_PARSE_NON_PARAMS_OPTIONS>(?=--))",  # double dash - starting the options list
+        DEST_VAR=r"(?P<DEST_VAR>[^\d\W]\w*)",  # essentially a Python ID
+    ),
+    state_parse_non_params_options=OrderedDict(
+        GOTO_PARSE_PARAMS_OPTION=r"(?P<GOTO_PARSE_PARAMS_OPTION>(?=--params(?:\s|=|--|$)))",  # the --params option
+        OPTION_SPEC=r"(?P<OPTION_SPEC>--\w+)",
+        OPTION_EQ=r"(?P<OPTION_EQ>=)",
+        OPT_VAL=r"(?P<OPT_VAL>\S+?(?=\s|--|$))",
+    ),
+    state_parse_params_option=OrderedDict(
+        PY_STRING=r"(?P<PY_STRING>(?:{})|(?:{}))".format(  # single and double quoted strings
+            r"'(?:[^'\\]|\.)*'", r'"(?:[^"\\]|\.)*"'
         ),
-    ]
+        PARAMS_OPT_SPEC=r"(?P<PARAMS_OPT_SPEC>--params(?=\s|=|--|$))",
+        PARAMS_OPT_EQ=r"(?P<PARAMS_OPT_EQ>=)",
+        GOTO_PARSE_NON_PARAMS_OPTIONS=r"(?P<GOTO_PARSE_NON_PARAMS_OPTIONS>(?=--\w+))",  # found another option spec
+        PY_BOOL=r"(?P<PY_BOOL>True|False)",
+        DOLLAR_PY_ID=r"(?P<DOLLAR_PY_ID>\$[^\d\W]\w*)",
+        PY_NUMBER=r"(?P<PY_NUMBER>-?[1-9]\d*(?:\.\d+)?(:?[e|E][+-]?\d+)?)",
+        SQUOTE=r"(?P<SQUOTE>')",
+        DQUOTE=r'(?P<DQUOTE>")',
+        COLON=r"(?P<COLON>:)",
+        COMMA=r"(?P<COMMA>,)",
+        LCURL=r"(?P<LCURL>\{)",
+        RCURL=r"(?P<RCURL>})",
+        LSQUARE=r"(?P<LSQUARE>\[)",
+        RSQUARE=r"(?P<RSQUARE>])",
+        LPAREN=r"(?P<LPAREN>\()",
+        RPAREN=r"(?P<RPAREN>\))",
+    ),
+    common=OrderedDict(
+        WS=r"(?P<WS>\s+)",
+        EOL=r"(?P<EOL>$)",
+        UNKNOWN=r"(?P<UNKNOWN>\S+)",  # anything not a whitespace or matched by something else
+    ),
 )
 
 
