diff options
Diffstat (limited to 'vendor/github.com/davecgh/go-spew/README.md')
| -rw-r--r-- | vendor/github.com/davecgh/go-spew/README.md | 205 |
1 files changed, 205 insertions, 0 deletions
diff --git a/vendor/github.com/davecgh/go-spew/README.md b/vendor/github.com/davecgh/go-spew/README.md new file mode 100644 index 000000000..262430449 --- /dev/null +++ b/vendor/github.com/davecgh/go-spew/README.md @@ -0,0 +1,205 @@ +go-spew +======= + +[] +(https://travis-ci.org/davecgh/go-spew) [![ISC License] +(http://img.shields.io/badge/license-ISC-blue.svg)](http://copyfree.org) [![Coverage Status] +(https://img.shields.io/coveralls/davecgh/go-spew.svg)] +(https://coveralls.io/r/davecgh/go-spew?branch=master) + + +Go-spew implements a deep pretty printer for Go data structures to aid in +debugging. A comprehensive suite of tests with 100% test coverage is provided +to ensure proper functionality. See `test_coverage.txt` for the gocov coverage +report. Go-spew is licensed under the liberal ISC license, so it may be used in +open source or commercial projects. + +If you're interested in reading about how this package came to life and some +of the challenges involved in providing a deep pretty printer, there is a blog +post about it +[here](https://web.archive.org/web/20160304013555/https://blog.cyphertite.com/go-spew-a-journey-into-dumping-go-data-structures/). + +## Documentation + +[] +(http://godoc.org/github.com/davecgh/go-spew/spew) + +Full `go doc` style documentation for the project can be viewed online without +installing this package by using the excellent GoDoc site here: +http://godoc.org/github.com/davecgh/go-spew/spew + +You can also view the documentation locally once the package is installed with +the `godoc` tool by running `godoc -http=":6060"` and pointing your browser to +http://localhost:6060/pkg/github.com/davecgh/go-spew/spew + +## Installation + +```bash +$ go get -u github.com/davecgh/go-spew/spew +``` + +## Quick Start + +Add this import line to the file you're working in: + +```Go +import "github.com/davecgh/go-spew/spew" +``` + +To dump a variable with full newlines, indentation, type, and pointer +information use Dump, Fdump, or Sdump: + +```Go +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): + +```Go +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) +``` + +## Debugging a Web Application Example + +Here is an example of how you can use `spew.Sdump()` to help debug a web application. Please be sure to wrap your output using the `html.EscapeString()` function for safety reasons. You should also only use this debugging technique in a development environment, never in production. + +```Go +package main + +import ( + "fmt" + "html" + "net/http" + + "github.com/davecgh/go-spew/spew" +) + +func handler(w http.ResponseWriter, r *http.Request) { + w.Header().Set("Content-Type", "text/html") + fmt.Fprintf(w, "Hi there, %s!", r.URL.Path[1:]) + fmt.Fprintf(w, "<!--\n" + html.EscapeString(spew.Sdump(w)) + "\n-->") +} + +func main() { + http.HandleFunc("/", handler) + http.ListenAndServe(":8080", nil) +} +``` + +## Sample Dump Output + +``` +(main.Foo) { + unexportedField: (*main.Bar)(0xf84002e210)({ + flag: (main.Flag) flagTwo, + data: (uintptr) <nil> + }), + ExportedField: (map[interface {}]interface {}) { + (string) "one": (bool) true + } +} +([]uint8) { + 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| +} +``` + +## 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>} +``` + +## 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. + +``` +* 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. This option + relies on access to the unsafe package, so it will not have any effect when + running in environments without access to the unsafe package such as Google + App Engine or with the "safe" build tag specified. + Pointer method invocation is enabled by default. + +* DisablePointerAddresses + DisablePointerAddresses specifies whether to disable the printing of + pointer addresses. This is useful when diffing data structures in tests. + +* DisableCapacities + DisableCapacities specifies whether to disable the printing of capacities + for arrays, slices, maps and channels. This is useful when diffing data + structures in tests. + +* 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 + 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. + +``` + +## Unsafe Package Dependency + +This package relies on the unsafe package to perform some of the more advanced +features, however it also supports a "limited" mode which allows it to work in +environments where the unsafe package is not available. By default, it will +operate in this mode on Google App Engine and when compiled with GopherJS. The +"safe" build tag may also be specified to force the package to build without +using the unsafe package. + +## License + +Go-spew is licensed under the [copyfree](http://copyfree.org) ISC License. |