13fc9b8d2f
Rather than stuffing a ConfigState instance into a separate SpewState,
just add the functionality directly to the ConfigState. This provides
simpler syntax for the consumer.
One side effect of this change is that, unlike a zero value SpewState, a
zero value ConfigState doesn't provide default values which means the
Indent field is set to provide no indentation. The consumer is now
expected to set the indent to their desired value when declaring an
instance of ConfigState.
Alternatively, the consumer can call a new function, NewDefaultConfig,
which returns a ConfigState with default values, including a default
indentation of a single space.
For example, to change the indent to a tab, the previous syntax was:
ss := new(spew.SpewState) // or var ss spew.SpewState
scs := ss.Config()
scs.Indent = "\t"
scs.Dump(whatever)
The new syntax is simply:
scs := spew.ConfigState{Indent: "\t"}
scs.Dump(whatever)
|
||
|---|---|---|
| spew | ||
| .gitignore | ||
| LICENSE | ||
| README.md | ||
README.md
go-spew
Go-spew implements a deep pretty printer for Go data structures to aid in debugging. It is still under initial development, so some of the formatting output is likely to change, however it is already quite capable. It 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 provide a deep pretty printer, there is a blog post about it here.
Documentation
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
$ go get github.com/davecgh/go-spew/spew
Quick Start
To dump a variable with full newlines, indentation, type, and pointer information use Dump or Fdump:
spew.Dump(myVar1, myVar2, ...)
spew.Fdump(someWriter, 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)
Sample Dump Output
(main.Foo) {
unexportedField: (*main.Bar)(0xf84002e210)({
flag: (main.Flag) flagTwo,
data: (uintptr) <nil>
}),
ExportedField: (map[interface {}]interface {}) {
(string) "one": (bool) true
}
}
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 SpewState instance which provides a unique ConfigState accessible via the Config method. The methods of SpewState are equivalent to the top-level functions. This allows concurrent configuration options. See the SpewState documentation for more details.
* MaxDepth
Maximum number of levels to descend into nested data structures.
There is no limit by default.
* Indent
String to use for each indentation level for Dump functions.
It is a single space by default. A popular alternative is "\t".
* 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.
License
Go-spew is licensed under the liberal ISC License.