Add deprecation comments to folly::makeFuture.

[folly.git] / folly / docs / Format.md

diff --git a/folly/docs/Format.md b/folly/docs/Format.md
index 012f0a28a3eac8fd9501451aa25b9e91e0041e77..b822c21a7591bf96ea27574aea0c56ffea760166 100644 (file)
--- a/folly/docs/Format.md
+++ b/folly/docs/Format.md
@@ -63,7 +63,7 @@ std::cout << format("The only {0[what]} is {0[value]}", m);
 // And if you just want the string,
 std::string result = svformat("The only {what} is {value}", m);
 // => "The only answer is 42"
-std::string result = svformat("The only {0[what]} is {0[value]}", m);
+std::string result = sformat("The only {0[what]} is {0[value]}", m);
 // => "The only answer is 42"
 
 // {} works for vformat too
@@ -82,6 +82,16 @@ std::cout << vformat("{0} {2} {1}", t);
 std::cout << format("{:X<10} {}", "hello", "world");
 // => "helloXXXXX world"
 
+// Field width may be a runtime value rather than part of the format string
+int x = 6;
+std::cout << format("{:-^*}", x, "hi");
+// => "--hi--"
+
+// Explicit arguments work with dynamic field width, as long as indexes are
+// given for both the value and the field width.
+std::cout << format("{2:+^*0}",
+9, "unused", 456); // => "+++456+++"
+
 // Format supports printf-style format specifiers
 std::cout << format("{0:05d} decimal = {0:04x} hex", 42);
 // => "00042 decimal = 002a hex"
@@ -142,7 +152,10 @@ Format specification:
   `0X` for hexadecimal; only valid for integers)
 - '`0`': 0-pad after sign, same as specifying "`0=`" as the `fill` and
   `align` parameters (only valid for numbers)
-- `width`: minimum field width
+- `width`: minimum field width. May be '`*`' to indicate that the field width
+  is given by an argument. Defaults to the next argument (preceding the value
+  to be formatted) but an explicit argument index may be given following the
+  '`*`'. Not supported in `vformat()`.
 - '`,`' (comma): output comma as thousands' separator (only valid for integers,
   and only for decimal output)
 - `precision` (not allowed for integers):
@@ -191,4 +204,3 @@ You can extend `format` for your own class by providing a specialization for
 `folly::FormatValue`.  See `folly/Format.h` and `folly/FormatArg.h` for
 details, and the existing specialization for `folly::dynamic` in
 `folly/dynamic-inl.h` for an implementation example.
-