vam: Add typeof() function

runtime/vam/expr/function/function.go

@@ -40,6 +40,8 @@ func New(zctx *zed.Context, name string, narg int) (expr.Function, field.Path, e
 		f = &Split{zctx}
 	case "trim":
 		f = &Trim{zctx}
+	case "typeof":
+		f = &TypeOf{zctx}
 	case "upper":
 		f = &ToUpper{zctx}
 	default:

runtime/vam/expr/function/types.go

@@ -0,0 +1,16 @@
+package function
+
+import (
+	"github.com/brimdata/zed"
+	"github.com/brimdata/zed/vector"
+)
+
+// https://github.com/brimdata/zed/blob/main/docs/language/functions.md#typeof
+type TypeOf struct {
+	zctx *zed.Context
+}
+
+func (t *TypeOf) Call(args ...vector.Any) vector.Any {
+	v := t.zctx.LookupTypeValue(args[0].Type())
+	return vector.NewConst(v, args[0].Len(), nil)
+}

runtime/ztests/expr/function/typeof.yaml

@@ -0,0 +1,68 @@
+zed: yield typeof(this)
+
+vector: true
+
+input: |
+  {
+      info: "Connection Example",
+      src: {
+          addr: 10.1.1.2,
+          port: 80 (uint16)
+      } (=socket),
+      dst: {
+          addr: 10.0.1.2,
+          port: 20130
+      } (socket)
+  } (=conn)
+  {
+      info: "Connection Example 2",
+      src: {
+          addr: 10.1.1.8,
+          port: 80 (uint16)
+      } (=socket),
+      dst: {
+          addr: 10.1.2.88,
+          port: 19801
+      } (socket)
+  } (=conn)
+  null(conn)
+  {
+      info: "Access List Example",
+      nets: [
+          10.1.1.0/24,
+          10.1.2.0/24
+      ]
+  } (=access_list)
+  {
+      metric: "A",
+      ts: 2020-11-24T16:44:09.586441Z,
+      value: 120
+  }
+  {
+      metric: "B",
+      ts: 2020-11-24T16:44:20.726057Z,
+      value: 0.86
+  }
+  {
+      metric: "A",
+      ts: 2020-11-24T16:44:32.201458Z,
+      value: 126
+  }
+  {
+      metric: "C",
+      ts: 2020-11-24T16:44:43.547506Z,
+      value: {
+          x: 10,
+          y: 101
+      }
+  }
+
+output: |
+  <conn={info:string,src:socket={addr:ip,port:uint16},dst:socket}>
+  <conn={info:string,src:socket={addr:ip,port:uint16},dst:socket}>
+  <conn={info:string,src:socket={addr:ip,port:uint16},dst:socket}>
+  <access_list={info:string,nets:[net]}>
+  <{metric:string,ts:time,value:int64}>
+  <{metric:string,ts:time,value:float64}>
+  <{metric:string,ts:time,value:int64}>
+  <{metric:string,ts:time,value:{x:int64,y:int64}}>