Merge pull request #922 from CleoQc/feature/support_scientific_notation

Feature/support scientific notation

CHANGES.rst

@@ -21,6 +21,8 @@ unreleased
 - Added a ``default`` parameter for the ``map`` filter. (`#557`_)
 -   Exclude environment globals from
     :func:`meta.find_undeclared_variables`. #931
+-   Float literals can be written with scientific notation, like
+    ``{{ 2.56e-3 }}``. #912, #922
 
 .. _#557: https://github.com/pallets/jinja/issues/557
 .. _#765: https://github.com/pallets/jinja/issues/765

docs/templates.rst

@@ -396,7 +396,7 @@ this template, it first locates the parent.  The extends tag should be the
 first tag in the template.  Everything before it is printed out normally and
 may cause confusion.  For details about this behavior and how to take
 advantage of it, see :ref:`null-master-fallback`. Also a block will always be
-filled in regardless of whether the surrounding condition is evaluated to be true 
+filled in regardless of whether the surrounding condition is evaluated to be true
 or false.
 
 The filename of the template depends on the template loader.  For example, the
@@ -1177,11 +1177,13 @@ for Python objects such as strings and numbers.  The following literals exist:
     arguments to function calls and filters, or just to extend or include a
     template).
 
-42 / 42.23:
-    Integers and floating point numbers are created by just writing the
-    number down.  If a dot is present, the number is a float, otherwise an
-    integer.  Keep in mind that, in Python, ``42`` and ``42.0``
-    are different (``int`` and ``float``, respectively).
+42:
+    Integers are whole numbers without a decimal part.
+
+42.23 / 42.1e2:
+    Floating point numbers can be written using a '.' as a decimal mark.
+    They can also be written in scientific notation with an upper or
+    lower case 'e' to indicate the exponent part.
 
 ['list', 'of', 'objects']:
     Everything between two brackets is a list.  Lists are useful for storing

jinja2/lexer.py

@@ -15,6 +15,7 @@
     :license: BSD, see LICENSE for more details.
 """
 import re
+from ast import literal_eval
 from collections import deque
 from operator import itemgetter
 
@@ -52,7 +53,7 @@ else:
     del jinja2._identifier
     del _identifier
 
-float_re = re.compile(r'(?<!\.)\d+\.\d+')
+float_re = re.compile(r'(?<!\.)\d+(?:\.\d+)?(?:e[+\-]?\d+)?', re.IGNORECASE)
 newline_re = re.compile(r'(\r\n|\r|\n)')
 
 # internal the tokens and keep references to them
@@ -601,7 +602,7 @@ class Lexer(object):
             elif token == 'integer':
                 value = int(value)
             elif token == 'float':
-                value = float(value)
+                value = literal_eval(value)
             elif token == 'operator':
                 token = operators[value]
             yield Token(lineno, token, value)

tests/test_filters.py

@@ -136,9 +136,11 @@ class TestFilter(object):
     def test_float(self, env):
         tmpl = env.from_string('{{ "42"|float }}|'
                                '{{ "ajsghasjgd"|float }}|'
+                               '{{ "10e1"|float }}|'
+                               '{{ "10.5e-10"|float }}|'
                                '{{ "32.32"|float }}')
         out = tmpl.render()
-        assert out == '42.0|0.0|32.32'
+        assert out == '42.0|0.0|100.0|1.05e-09|32.32'
 
     def test_format(self, env):
         tmpl = env.from_string('''{{ "%s|%s"|format("a", "b") }}''')

tests/test_lexnparse.py

@@ -336,9 +336,36 @@ class TestSyntax(object):
         tmpl = env.from_string('{{ 1 in [1, 2, 3] }}|{{ 1 not in [1, 2, 3] }}')
         assert tmpl.render() == 'True|False'
 
-    def test_literals(self, env):
-        tmpl = env.from_string('{{ [] }}|{{ {} }}|{{ () }}')
-        assert tmpl.render().lower() == '[]|{}|()'
+    @pytest.mark.parametrize("value", ("[]", "{}", "()"))
+    def test_collection_literal(self, env, value):
+        t = env.from_string("{{ %s }}" % value)
+        assert t.render() == value
+
+    @pytest.mark.parametrize("value", ("1", "123"))
+    def test_int_literal(self, env, value):
+        t = env.from_string("{{ %s }}" % value)
+        assert t.render() == value
+
+    @pytest.mark.parametrize(
+        "value",
+        (
+            "1.2",
+            "34.56",
+            ("1e0", "1.0"),
+            ("10e1", "100.0"),
+            ("2.5e100", "2.5e+100"),
+            "2.5e+100",
+            ("25.6e-10", "2.56e-09"),
+        ),
+    )
+    def test_float_literal(self, env, value):
+        if isinstance(value, tuple):
+            value, expect = value
+        else:
+            expect = value
+
+        t = env.from_string("{{ %s }}" % value)
+        assert t.render() == expect
 
     def test_bool(self, env):
         tmpl = env.from_string('{{ true and false }}|{{ false '