[Python-checkins] cpython (3.6): Update docs to reflect new behavior around backslashes in expressions (not

Sun Nov 6 11:27:39 EST 2016

https://hg.python.org/cpython/rev/d9eb609be2ca
changeset: 104928:d9eb609be2ca
branch: 3.6
user: Jason R. Coombs <jaraco at jaraco.com>
date: Sun Nov 06 11:27:17 2016 -0500
summary:
 Update docs to reflect new behavior around backslashes in expressions (not allowed), matching recent changes to PEP 498.
files:
 Doc/reference/lexical_analysis.rst | 19 +++++++++++------
 1 files changed, 12 insertions(+), 7 deletions(-)

diff --git a/Doc/reference/lexical_analysis.rst b/Doc/reference/lexical_analysis.rst
--- a/Doc/reference/lexical_analysis.rst
+++ b/Doc/reference/lexical_analysis.rst
@@ -679,17 +679,22 @@
 
 A consequence of sharing the same syntax as regular string literals is
 that characters in the replacement fields must not conflict with the
-quoting used in the outer formatted string literal. Also, escape
-sequences normally apply to the outer formatted string literal,
-rather than inner string literals::
+quoting used in the outer formatted string literal::
 
 f"abc {a["x"]} def" # error: outer string literal ended prematurely
- f"abc {a[\"x\"]} def" # workaround: escape the inner quotes
 f"abc {a['x']} def" # workaround: use different quoting
 
- f"newline: {ord('\n')}" # error: literal line break in inner string
- f"newline: {ord('\\n')}" # workaround: double escaping
- fr"newline: {ord('\n')}" # workaround: raw outer string
+Backslashes are not allowed in format expressions and will raise
+an error::
+
+ f"newline: {ord('\n')}" # raises SyntaxError
+
+To include a value in which a backslash escape is required, create
+a temporary variable.
+
+ >>> newline = ord('\n')
+ >>> f"newline: {newline}"
+ 'newline: 10'
 
 See also :pep:`498` for the proposal that added formatted string literals,
 and :meth:`str.format`, which uses a related format string mechanism.
-- 
Repository URL: https://hg.python.org/cpython
