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mirror of https://github.com/MontFerret/ferret.git synced 2024-12-16 11:37:36 +02:00
ferret/examples/extensible.go
3timeslazy acf2f13dcb Linter Cleanups (#294)
* sync with MontFerret/ferret

* fix --param handling

When params is converted to map it uses strings.Split,
which slices a string into all substrings separated by :.

* remove impossible conditions nil != nil

* delete ineffectual assignments

* replace '+= 1' with '++'

* remove useless comparison with nil

* merge variable declarations

* remove bool comparison

* fix imports

* fix imports

* delete unused file

* use copy instead of loop

* delete unused DummyInterface

* remove unnecassary break statements

* tidy modules
2019-05-03 17:10:34 -04:00

87 lines
1.7 KiB
Go

package main
import (
"context"
"encoding/json"
"fmt"
"os"
"strings"
"github.com/MontFerret/ferret/pkg/compiler"
"github.com/MontFerret/ferret/pkg/runtime/core"
"github.com/MontFerret/ferret/pkg/runtime/values"
"github.com/MontFerret/ferret/pkg/runtime/values/types"
)
func main() {
strs, err := getStrings()
if err != nil {
fmt.Println(err)
os.Exit(1)
}
for _, str := range strs {
fmt.Println(str)
}
}
func getStrings() ([]string, error) {
// function implements is a type of a function that ferret supports as a runtime function
transform := func(ctx context.Context, args ...core.Value) (core.Value, error) {
// it's just a helper function which helps to validate a number of passed args
err := core.ValidateArgs(args, 1, 1)
if err != nil {
// it's recommended to return built-in None type, instead of nil
return values.None, err
}
// this is another helper functions allowing to do type validation
err = core.ValidateType(args[0], types.String)
if err != nil {
return values.None, err
}
// cast to built-in string type
str := args[0].(values.String)
return values.NewString(strings.ToUpper(str.String() + "_ferret")), nil
}
query := `
FOR el IN ["foo", "bar", "qaz"]
// conventionally all functions are registered in upper case
RETURN TRANSFORM(el)
`
comp := compiler.New()
if err := comp.RegisterFunction("transform", transform); err != nil {
return nil, err
}
program, err := comp.Compile(query)
if err != nil {
return nil, err
}
out, err := program.Run(context.Background())
if err != nil {
return nil, err
}
res := make([]string, 0, 3)
err = json.Unmarshal(out, &res)
if err != nil {
return nil, err
}
return res, nil
}