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author | =Corey Hulen <corey@hulen.com> | 2015-11-23 15:53:48 -0800 |
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committer | =Corey Hulen <corey@hulen.com> | 2015-11-23 15:53:48 -0800 |
commit | 4f4cd5e63573da4d6edcc7d4213afaca67c19f88 (patch) | |
tree | cefbc7af53629d97644ca2f6b2369e9d879f0101 /Godeps/_workspace/src/github.com/davecgh/go-spew/spew/doc.go | |
parent | f8a3c9a14edca6df0647d89cf225f2470cbe025c (diff) | |
download | chat-4f4cd5e63573da4d6edcc7d4213afaca67c19f88.tar.gz chat-4f4cd5e63573da4d6edcc7d4213afaca67c19f88.tar.bz2 chat-4f4cd5e63573da4d6edcc7d4213afaca67c19f88.zip |
upgrading libs
Diffstat (limited to 'Godeps/_workspace/src/github.com/davecgh/go-spew/spew/doc.go')
-rw-r--r-- | Godeps/_workspace/src/github.com/davecgh/go-spew/spew/doc.go | 202 |
1 files changed, 202 insertions, 0 deletions
diff --git a/Godeps/_workspace/src/github.com/davecgh/go-spew/spew/doc.go b/Godeps/_workspace/src/github.com/davecgh/go-spew/spew/doc.go new file mode 100644 index 000000000..5be0c4060 --- /dev/null +++ b/Godeps/_workspace/src/github.com/davecgh/go-spew/spew/doc.go @@ -0,0 +1,202 @@ +/* + * Copyright (c) 2013 Dave Collins <dave@davec.name> + * + * Permission to use, copy, modify, and distribute this software for any + * purpose with or without fee is hereby granted, provided that the above + * copyright notice and this permission notice appear in all copies. + * + * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES + * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF + * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR + * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES + * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN + * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF + * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. + */ + +/* +Package spew implements a deep pretty printer for Go data structures to aid in +debugging. + +A quick overview of the additional features spew provides over the built-in +printing facilities for Go data types are as follows: + + * Pointers are dereferenced and followed + * Circular data structures are detected and handled properly + * Custom Stringer/error interfaces are optionally invoked, including + on unexported types + * Custom types which only implement the Stringer/error interfaces via + a pointer receiver are optionally invoked when passing non-pointer + variables + * Byte arrays and slices are dumped like the hexdump -C command which + includes offsets, byte values in hex, and ASCII output (only when using + Dump style) + +There are two different approaches spew allows for dumping Go data structures: + + * Dump style which prints with newlines, customizable indentation, + and additional debug information such as types and all pointer addresses + used to indirect to the final value + * A custom Formatter interface that integrates cleanly with the standard fmt + package and replaces %v, %+v, %#v, and %#+v to provide inline printing + similar to the default %v while providing the additional functionality + outlined above and passing unsupported format verbs such as %x and %q + along to fmt + +Quick Start + +This section demonstrates how to quickly get started with spew. See the +sections below for further details on formatting and configuration options. + +To dump a variable with full newlines, indentation, type, and pointer +information use Dump, Fdump, or Sdump: + spew.Dump(myVar1, myVar2, ...) + spew.Fdump(someWriter, myVar1, myVar2, ...) + str := spew.Sdump(myVar1, myVar2, ...) + +Alternatively, if you would prefer to use format strings with a compacted inline +printing style, use the convenience wrappers Printf, Fprintf, etc with +%v (most compact), %+v (adds pointer addresses), %#v (adds types), or +%#+v (adds types and pointer addresses): + spew.Printf("myVar1: %v -- myVar2: %+v", myVar1, myVar2) + spew.Printf("myVar3: %#v -- myVar4: %#+v", myVar3, myVar4) + spew.Fprintf(someWriter, "myVar1: %v -- myVar2: %+v", myVar1, myVar2) + spew.Fprintf(someWriter, "myVar3: %#v -- myVar4: %#+v", myVar3, myVar4) + +Configuration Options + +Configuration of spew is handled by fields in the ConfigState type. For +convenience, all of the top-level functions use a global state available +via the spew.Config global. + +It is also possible to create a ConfigState instance that provides methods +equivalent to the top-level functions. This allows concurrent configuration +options. See the ConfigState documentation for more details. + +The following configuration options are available: + * Indent + String to use for each indentation level for Dump functions. + It is a single space by default. A popular alternative is "\t". + + * MaxDepth + Maximum number of levels to descend into nested data structures. + There is no limit by default. + + * DisableMethods + Disables invocation of error and Stringer interface methods. + Method invocation is enabled by default. + + * DisablePointerMethods + Disables invocation of error and Stringer interface methods on types + which only accept pointer receivers from non-pointer variables. + Pointer method invocation is enabled by default. + + * ContinueOnMethod + Enables recursion into types after invoking error and Stringer interface + methods. Recursion after method invocation is disabled by default. + + * SortKeys + Specifies map keys should be sorted before being printed. Use + this to have a more deterministic, diffable output. Note that + only native types (bool, int, uint, floats, uintptr and string) + and types which implement error or Stringer interfaces are + supported with other types sorted according to the + reflect.Value.String() output which guarantees display + stability. Natural map order is used by default. + + * SpewKeys + Specifies that, as a last resort attempt, map keys should be + spewed to strings and sorted by those strings. This is only + considered if SortKeys is true. + +Dump Usage + +Simply call spew.Dump with a list of variables you want to dump: + + spew.Dump(myVar1, myVar2, ...) + +You may also call spew.Fdump if you would prefer to output to an arbitrary +io.Writer. For example, to dump to standard error: + + spew.Fdump(os.Stderr, myVar1, myVar2, ...) + +A third option is to call spew.Sdump to get the formatted output as a string: + + str := spew.Sdump(myVar1, myVar2, ...) + +Sample Dump Output + +See the Dump example for details on the setup of the types and variables being +shown here. + + (main.Foo) { + unexportedField: (*main.Bar)(0xf84002e210)({ + flag: (main.Flag) flagTwo, + data: (uintptr) <nil> + }), + ExportedField: (map[interface {}]interface {}) (len=1) { + (string) (len=3) "one": (bool) true + } + } + +Byte (and uint8) arrays and slices are displayed uniquely like the hexdump -C +command as shown. + ([]uint8) (len=32 cap=32) { + 00000000 11 12 13 14 15 16 17 18 19 1a 1b 1c 1d 1e 1f 20 |............... | + 00000010 21 22 23 24 25 26 27 28 29 2a 2b 2c 2d 2e 2f 30 |!"#$%&'()*+,-./0| + 00000020 31 32 |12| + } + +Custom Formatter + +Spew provides a custom formatter that implements the fmt.Formatter interface +so that it integrates cleanly with standard fmt package printing functions. The +formatter is useful for inline printing of smaller data types similar to the +standard %v format specifier. + +The custom formatter only responds to the %v (most compact), %+v (adds pointer +addresses), %#v (adds types), or %#+v (adds types and pointer addresses) verb +combinations. Any other verbs such as %x and %q will be sent to the the +standard fmt package for formatting. In addition, the custom formatter ignores +the width and precision arguments (however they will still work on the format +specifiers not handled by the custom formatter). + +Custom Formatter Usage + +The simplest way to make use of the spew custom formatter is to call one of the +convenience functions such as spew.Printf, spew.Println, or spew.Printf. The +functions have syntax you are most likely already familiar with: + + spew.Printf("myVar1: %v -- myVar2: %+v", myVar1, myVar2) + spew.Printf("myVar3: %#v -- myVar4: %#+v", myVar3, myVar4) + spew.Println(myVar, myVar2) + spew.Fprintf(os.Stderr, "myVar1: %v -- myVar2: %+v", myVar1, myVar2) + spew.Fprintf(os.Stderr, "myVar3: %#v -- myVar4: %#+v", myVar3, myVar4) + +See the Index for the full list convenience functions. + +Sample Formatter Output + +Double pointer to a uint8: + %v: <**>5 + %+v: <**>(0xf8400420d0->0xf8400420c8)5 + %#v: (**uint8)5 + %#+v: (**uint8)(0xf8400420d0->0xf8400420c8)5 + +Pointer to circular struct with a uint8 field and a pointer to itself: + %v: <*>{1 <*><shown>} + %+v: <*>(0xf84003e260){ui8:1 c:<*>(0xf84003e260)<shown>} + %#v: (*main.circular){ui8:(uint8)1 c:(*main.circular)<shown>} + %#+v: (*main.circular)(0xf84003e260){ui8:(uint8)1 c:(*main.circular)(0xf84003e260)<shown>} + +See the Printf example for details on the setup of variables being shown +here. + +Errors + +Since it is possible for custom Stringer/error interfaces to panic, spew +detects them and handles them internally by printing the panic information +inline with the output. Since spew is intended to provide deep pretty printing +capabilities on structures, it intentionally does not return any errors. +*/ +package spew |