don't go ham on removing fmt useful data

.github/workflows/ci.yaml

@@ -143,6 +143,12 @@ jobs:
       - uses: actions/setup-go@v6
         with:
           go-version: "1.26"
+      # Needed because a build command in memci.json names tinygo. Keep the two
+      # versions in step: TinyGo 0.42 builds with Go 1.25 through 1.27 and
+      # refuses to run outside that window, in either direction.
+      - uses: acifani/setup-tinygo@v2
+        with:
+          tinygo-version: "0.42.0"
       - uses: soypat/memci@main
         with:
           args: -kind package

.github/workflows/memci-comment.yml

@@ -6,7 +6,7 @@ name: memci comment
 
 on:
   workflow_run:
-    workflows: [memci]
+    workflows: [CI]
     types: [completed]
 
 permissions: read-all

.github/workflows/memci.json

@@ -3,5 +3,11 @@
         "name":"Stack MWE",
         "build":"go build -o=mwe.elf -tags=noslog ./examples/min-working-example",
         "elf":"mwe.elf"
+    },
+    {
+        "name":"Stack MWE pico",
+        "build":"tinygo build -o=mwe-pico.elf -target=pico -tags=noslog -panic=trap ./examples/min-working-example",
+        "elf":"mwe-pico.elf",
+        "mem":true
     }
-]
+]

arp/frame.go

@@ -5,6 +5,7 @@ import (
 
 	"github.com/soypat/lneto"
 	"github.com/soypat/lneto/ethernet"
+	"github.com/soypat/lneto/internal"
 )
 
 // NewFrame returns a Frame with data set to buf.
@@ -142,10 +143,24 @@ func (afrm Frame) ValidateSize(v *lneto.Validator) {
 	}
 }
 
+// String returns a basic human readable represetation of ARP frame.
 func (afrm Frame) String() string {
 	opstr := afrm.Operation().String()
-	var rawbuf [11]byte
+	rawbuf := make([]byte, 0, 128)
 	b := append(rawbuf[:0], "ARP "...)
 	b = append(b, opstr...)
-	return string(rawbuf[:len(b)])
+	htyp, hlen := afrm.Hardware()
+	b = internal.AppendStrDecimal(b, " htyp=", int64(htyp))
+	b = internal.AppendStrDecimal(b, " hlen=", int64(hlen))
+	ptyp, plen := afrm.Protocol()
+	b = internal.AppendStrDecimal(b, " plen=", int64(plen))
+	b = append(b, " proto="...)
+	b = append(b, ptyp.String()...)
+	hw, proto := afrm.Target()
+	b = internal.AppendStrHexData(b, " htgt=", hw...)
+	b = internal.AppendStrHexData(b, " ptgt=", proto...)
+	hw, proto = afrm.Sender()
+	b = internal.AppendStrHexData(b, " hsnd=", hw...)
+	b = internal.AppendStrHexData(b, " psnd=", proto...)
+	return string(b)
 }

internal/strconv.go

@@ -1,6 +1,9 @@
 package internal
 
-import "strconv"
+import (
+	"encoding/hex"
+	"strconv"
+)
 
 // AppendStrDecimal appends pfx followed by value in base 10 to dst and returns
 // the resulting slice. It condenses the prefixed-number pattern common to
@@ -10,6 +13,14 @@ func AppendStrDecimal(dst []byte, pfx string, value int64) []byte {
 	return strconv.AppendInt(dst, value, 10)
 }
 
+// AppendStrHexData appends pfx followed by data as hexadecimaldata.
+//
+//	dst = internal.AppendStrHexData(dst, "data=0x", data...) // data=0xdeadbeef
+func AppendStrHexData(dst []byte, pfx string, data ...byte) []byte {
+	dst = append(dst, pfx...)
+	return hex.AppendEncode(dst, data)
+}
+
 // IntLen returns the number of bytes [strconv.AppendInt] emits for value in the
 // given base, including a leading minus sign for negatives. Lets callers size a
 // buffer, or test whether a value fits an existing slot, before writing a byte.

ipv4/frame.go

@@ -4,6 +4,7 @@ import (
 	"encoding/binary"
 
 	"github.com/soypat/lneto"
+	"github.com/soypat/lneto/internal"
 )
 
 // NewFrame returns a new [Frame] with data set to buf.
@@ -237,9 +238,17 @@ func (ifrm Frame) ValidateExceptCRC(v *lneto.Validator) {
 
 func (ifrm Frame) String() string {
 	proto := ifrm.Protocol().String()
-	b := make([]byte, 0, 5+len(proto))
+	b := make([]byte, 0, 91+len(proto))
 	b = append(b, "IP ("...)
 	b = append(b, proto...)
-	b = append(b, ')')
+	b = append(b, ") src="...)
+	b = AppendFormatAddr(b, *ifrm.SourceAddr())
+	b = append(b, " dst="...)
+	b = AppendFormatAddr(b, *ifrm.DestinationAddr())
+	b = internal.AppendStrDecimal(b, " len=", int64(ifrm.TotalLength()))
+	b = internal.AppendStrDecimal(b, " opt=", int64(ifrm.HeaderLength()-20))
+	b = internal.AppendStrDecimal(b, " ttl=", int64(ifrm.TTL()))
+	b = internal.AppendStrDecimal(b, " id=", int64(ifrm.ID()))
+	b = internal.AppendStrHexData(b, " tos=0x", byte(ifrm.ToS()))
 	return string(b)
 }