Don't parse 5.attr or :foo.attr as symbols

NEWS

@@ -3,6 +3,11 @@ Changes from 0.13.0
    [ Language Changes ]
    * Single-character "sharp macros" changed to "tag macros", which can have
      longer names
+   * Periods are no longer allowed in keywords
+
+   [ Bug Fixes ]
+   * Numeric literals are no longer parsed as symbols when followed by a dot
+     and a symbol
 
 Changes from 0.12.1
 

hy/lex/parser.py

@@ -288,6 +288,24 @@ def t_partial_string(p):
 def t_identifier(p):
     obj = p[0].value
 
+    val = symbol_like(obj)
+    if val is not None:
+        return val
+
+    if "." in obj and symbol_like(obj.split(".", 1)[0]) is not None:
+        # E.g., `5.attr` or `:foo.attr`
+        raise LexException(
+            'Cannot access attribute on anything other than a name (in '
+            'order to get attributes of expressions, use '
+            '`(. <expression> <attr>)` or `(.<attr> <expression>)`)',
+            p[0].source_pos.lineno, p[0].source_pos.colno)
+
+    return HySymbol(".".join(hy_symbol_mangle(x) for x in obj.split(".")))
+
+
+def symbol_like(obj):
+    "Try to interpret `obj` as a number or keyword."
+
     try:
         return HyInteger(obj)
     except ValueError:
@@ -312,13 +330,9 @@ def t_identifier(p):
         except ValueError:
             pass
 
-    if obj.startswith(":"):
+    if obj.startswith(":") and "." not in obj:
         return HyKeyword(obj)
 
-    obj = ".".join([hy_symbol_mangle(part) for part in obj.split(".")])
-
-    return HySymbol(obj)
-
 
 @pg.error
 def error_handler(token):

tests/native_tests/language.hy

@@ -1446,7 +1446,6 @@
   (assert (= (keyword 'foo) :foo))
   (assert (= (keyword 'foo-bar) :foo-bar))
   (assert (= (keyword 1) :1))
-  (assert (= (keyword 1.0) :1.0))
   (assert (= (keyword :foo_bar) :foo-bar)))
 
 (defn test-name-conversion []

tests/test_lex.py

@@ -129,6 +129,21 @@ def test_lex_digit_separators():
             [HySymbol(",,,,___,__1__,,__,,2__,q,__")])
 
 
+def test_lex_bad_attrs():
+    with lexe(): tokenize("1.foo")
+    with lexe(): tokenize("0.foo")
+    with lexe(): tokenize("1.5.foo")
+    with lexe(): tokenize("1e3.foo")
+    with lexe(): tokenize("5j.foo")
+    with lexe(): tokenize("3+5j.foo")
+    with lexe(): tokenize("3.1+5.1j.foo")
+    assert tokenize("j.foo")
+    with lexe(): tokenize("3/4.foo")
+    assert tokenize("a/1.foo")
+    assert tokenize("1/a.foo")
+    with lexe(): tokenize(":hello.foo")
+
+
 def test_lex_line_counting():
     """ Make sure we can count lines / columns """
     entry = tokenize("(foo (one two))")[0]