frostfs-node/pkg/policy/grammar.go
Evgenii Stratonikov d7c53debb5 [#46] Make SELECT attribute optional
Signed-off-by: Evgenii Stratonikov <evgeniy@nspcc.ru>
2020-10-16 16:15:27 +03:00

59 lines
1.1 KiB
Go

package policy
import (
"github.com/alecthomas/participle"
)
var parser *participle.Parser
func init() {
p, err := participle.Build(&query{})
if err != nil {
panic(err)
}
parser = p
}
type query struct {
Replicas []*replicaStmt `@@+`
CBF uint32 `("CBF" @Int)?`
Selectors []*selectorStmt `@@*`
Filters []*filterStmt `@@*`
}
type replicaStmt struct {
Count int `"REP" @Int`
Selector string `("IN" @Ident)?`
}
type selectorStmt struct {
Count uint32 `"SELECT" @Int`
Bucket []string `("IN" @(("SAME" | "DISTINCT")? Ident))?`
Filter string `"FROM" @(Ident | "*")`
Name string `("AS" @Ident)?`
}
type filterStmt struct {
Value *orChain `"FILTER" @@`
Name string `"AS" @Ident`
}
type filterOrExpr struct {
Reference string `"@"@Ident`
Expr *simpleExpr `| @@`
}
type orChain struct {
Clauses []*andChain `@@ ("OR" @@)*`
}
type andChain struct {
Clauses []*filterOrExpr `@@ ("AND" @@)*`
}
type simpleExpr struct {
Key string `@Ident`
// We don't use literals here to improve error messages.
Op string `@Ident`
Value string `@(Ident | String | Int)`
}