From: Eric V. Smith <eric@trueblade.com>
Date: Tue, 3 Nov 2015 18:09:01 +0000 (-0500)
Subject: Issue 25483: Update dis.rst with FORMAT_VALUE opcode description.
X-Git-Tag: v3.6.0a1~1131
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=281d5321a3bdee1fd7091e439855c0358371216c;p=python

Issue 25483: Update dis.rst with FORMAT_VALUE opcode description.
---

diff --git a/Doc/library/dis.rst b/Doc/library/dis.rst
index 1bcb3a4a07..c6e1656786 100644
--- a/Doc/library/dis.rst
+++ b/Doc/library/dis.rst
@@ -989,6 +989,25 @@ the more significant byte last.
    arguments.
 
 
+.. opcode:: FORMAT_VALUE (flags)
+
+   Used for implementing formatted literal strings (f-strings).  Pops
+   an optional *fmt_spec* from the stack, then a required *value*.
+   *flags* is interpreted as follows:
+
+   * ``(flags & 0x03) == 0x00``: *value* is formattedd as-is.
+   * ``(flags & 0x03) == 0x01``: call :func:`str` on *value* before
+     formatting it.
+   * ``(flags & 0x03) == 0x02``: call :func:`repr` on *value* before
+     formatting it.
+   * ``(flags & 0x03) == 0x03``: call :func:`ascii` on *value* before
+     formatting it.
+   * ``(flags & 0x04) == 0x04``: pop *fmt_spec* from the stack and use
+     it, else use an empty *fmt_spec*.
+
+   Formatting is performed using the :c:func:`PyObject_Format` function.
+
+
 .. opcode:: HAVE_ARGUMENT
 
    This is not really an opcode.  It identifies the dividing line between