Auto-defuse SUP output

[mattnibs]

This pr adds functionality to auto-defuse fusion values in SUP output. If the -fusion flag is enabled, fusion values will be displayed.

[nwt]

This change creates a lot of extra work for the garbage collector on each parse_sup() call. I wouldn't cry about that if there were no other way to avoid the import cycle, but how about doing it in anyio instead of supio?

--- a/sio/anyio/writer.go
+++ b/sio/anyio/writer.go
@@ -4,7 +4,11 @@ import (
        "fmt"
        "io"

+       "github.com/brimdata/super"
        "github.com/brimdata/super/csup"
+       "github.com/brimdata/super/runtime/sam/expr"
+       "github.com/brimdata/super/runtime/sam/expr/function"
+       "github.com/brimdata/super/sbuf"
        "github.com/brimdata/super/sio/arrowio"
        "github.com/brimdata/super/sio/bsupio"
        "github.com/brimdata/super/sio/csvio"
@@ -20,12 +24,13 @@ import (
 )

 type WriterOpts struct {
-       Format string
-       BSUP   *bsupio.WriterOpts // Nil means use defaults via bsupio.NewWriter.
-       CSV    csvio.WriterOpts
-       DB     dbio.WriterOpts
-       JSON   jsonio.WriterOpts
-       SUP    supio.WriterOpts
+       Format    string
+       SUPFusion bool
+       BSUP      *bsupio.WriterOpts // Nil means use defaults via bsupio.NewWriter.
+       CSV       csvio.WriterOpts
+       DB        dbio.WriterOpts
+       JSON      jsonio.WriterOpts
+       SUP       supio.WriterOpts
 }

 func NewWriter(w io.WriteCloser, opts WriterOpts) (vio.PushCloser, error) {
@@ -52,7 +57,11 @@ func NewWriter(w io.WriteCloser, opts WriterOpts) (vio.PushCloser, error) {
        case "parquet":
                return parquetio.NewWriter(w), nil
        case "sup", "":
-               return supio.NewWriter(w, opts.SUP), nil
+               w := supio.NewWriter(w, opts.SUP)
+               if !opts.SUPFusion {
+                       return &supDefuser{w, function.NewDefuse(super.NewContext())}, nil
+               }
+               return w, nil
        case "table":
                return tableio.NewWriter(w), nil
        case "tsv":
@@ -65,6 +74,21 @@ func NewWriter(w io.WriteCloser, opts WriterOpts) (vio.PushCloser, error) {
        }
 }

+type supDefuser struct {
+       *supio.Writer
+       defuse expr.Function
+}
+
+func (d *supDefuser) Push(vec vector.Any) error {
+       for _, val := range sbuf.Materialize(vec).Values() {
+               val = d.defuse.Call([]super.Value{val})
+               if err := d.Writer.Write(val); err != nil {
+                       return err
+               }
+       }
+       return nil
+}
+

[mattnibs]

Ugh I really don't have like having surprising behavior like this.

[mattnibs]

I'd honestly rather just duplicate the code in supio.Reader in sam/expr/function.ParseSUP.