Weave provides the ability to turn data stored in arbitrary structs of arbitrary depth into exportable formats like CSV or JSON. It supports field selection, named/unnamed structs, and embeds.
Basic usage is via the output modules (To*). Simply pass your array of the same struct to an output module along with the fully qualified (more on this below) names of the columns you want outputted.
Ex: out := ToCSV(data, []string{"fieldname", "structname.anotherinnerstruct.fieldname"})
Call StructField() on your struct to see the full, qualified names of every field at every depth.
type someEmbed struc {
Fld int
}
type someData struct {
someEmbed
A int
}
data := someData{someEmbed: someEmbed{Fld: 5}, A: 10}
output := ToCSV(data, []string{"A"})
fmt.Println(output)See the test suite in weave_test for more usage examples.
Column names are dot qualified and follow Go's rules for struct nesting and promotion. They are all compatible with Gabs paths.
To repeat: call StructField() on your struct to see the full, qualified names of every field at every depth.
type A struct {
a int
b int
C int
}Can be accessed directly ("a", "b", "C").
type mbd struct {
X string
z string
}
type A struct {
a int
b int
C int
mbd
}Embedded field are accessed as "X" and "z".
type deep struct {
F float 64
}
type shallow struct {
D deep
X string
z string
}
type A struct {
a int
b int
C int
i inner
}"i.D.F", "i.z"
- Column names (and qualifications) are case sensitive
-
Encoding/json does not accept complex numbers. Weave can by converting them to a generic struct and outputing the struct as JSON objects with the fields "Real" and "Imaginary".
-
As with normal JSON encoding, only exported struct fields can be output.
The blacklist parameter is currently ineffectual due to a bug in how the JSON library (Gabs) .Wrap()s existing structures. I have opened a PR #142 to fix this.
This function will instead output ALL exported fields at all depths.
- Create ToCSVExclude, consuming column list as blacklist
- Make qualified column names case-insensitive