Simple library to match regex expression named groups into go struct using struct tags and automatic parsing
go get github.com/oriser/regroup
package main
import (
"fmt"
"github.com/oriser/regroup"
)
var re = regroup.MustCompile(`(?P<duration>.*?)\s+(?P<num>\d+)\s+(?P<foo>.*)`)
func main() {
matches, err := re.Groups("5s 123 bar")
if err != nil {
panic(err)
}
fmt.Printf("%+v\n", matches)
}Will output:
map[duration:5s foo:bar num:123]
package main
import (
"fmt"
"github.com/oriser/regroup"
"time"
)
var re = regroup.MustCompile(`(?P<duration>.*?)\s+(?P<num>\d+)\s+(?P<foo>.*)`)
type B struct {
Str string `regroup:"foo"`
}
type A struct {
Number int `regroup:"num"`
Dur time.Duration `regroup:"duration"`
AnotherStruct B
}
func main() {
a := &A{}
if err := re.MatchToTarget("5s 123 bar", a); err != nil {
panic(err)
}
fmt.Printf("%+v\n", a)
}Will output:
&{Number:123 Dur:5s AnotherStruct:{Str:bar}}
You can also get all matches parsed as given target struct. The return value in this case will be an array of interfaces, you should cast it to the target type in order to access its fields.
package main
import (
"fmt"
"github.com/oriser/regroup"
"time"
)
var re = regroup.MustCompile(`\s*(?P<duration>.*?)\s+(?P<num>\d+)\s+(?P<foo>.*)`)
type B struct {
Str string `regroup:"foo"`
}
type A struct {
Number int `regroup:"num"`
Dur time.Duration `regroup:"duration"`
AnotherStruct B
}
func main() {
a := &A{}
s := `5s 123 bar1
1m 456 bar2
10h 789 bar3`
rets, err := re.MatchAllToTarget(s, -1, a)
if err != nil {
panic(err)
}
for _, elem := range rets {
fmt.Printf("%+v\n", elem.(*A))
}
}Will output:
&{Number:123 Dur:5s AnotherStruct:{Str:bar1}}
&{Number:456 Dur:1m0s AnotherStruct:{Str:bar2}}
&{Number:789 Dur:10h0m0s AnotherStruct:{Str:bar3}}
You can specify that a specific group is required, means that it can't be empty.
If a required group is empty, an error (*regroup.RequiredGroupIsEmpty) will be returned .
package main
import (
"fmt"
"github.com/oriser/regroup"
"time"
)
var re = regroup.MustCompile(`(?P<duration>.*?)\s+(?P<num>\d+)\s+(?P<foo>.*)`)
type B struct {
Str string `regroup:"foo,required"`
}
type A struct {
Number int `regroup:"num"`
Dur time.Duration `regroup:"duration"`
AnotherStruct B
}
func main() {
a := &A{}
if err := re.MatchToTarget("5s 123 ", a); err != nil {
panic(err)
}
fmt.Printf("%+v\n", a)
}Will return an error: required regroup "foo" is empty for field "Str"
You can check for the presence of an optional group using a bool with the exists tag.
package main
type Exist struct {
IsAdmin bool `regroup:"is_admin,exists"`
}
func main() {
r := MustCompile(`^(?P<name>\w*)(?:,(?P<is_admin>admin))?$`)
parsed := &Exist{}
if err := r.MatchToTarget("bob_smith", parsed); err != nil {
panic(err)
}
fmt.Printf("%t\n", parsed.IsAdmin)
}This example would print false. However if the input were bob_smith,admin it would print true. When using the exists tag, make ure that you regular expression has an optional group and matches all the expected input patterns.
time.Durationboolstringintint8int16int32int64uintuint8uint16uint32uint64float32float64
Pointers and nested structs are also supported, both on single match and multiple matches