interp: Add Platform() method to OS interface

Felt bad that main should have to know about it

fq.go

@@ -1,8 +1,6 @@
 package main
 
 import (
-	"runtime"
-
 	_ "github.com/wader/fq/format/all"
 	"github.com/wader/fq/format/registry"
 	"github.com/wader/fq/pkg/cli"
@@ -11,5 +9,5 @@ import (
 const version = "0.0.4"
 
 func main() {
-	cli.Main(registry.Default, version, runtime.GOOS, runtime.GOARCH)
+	cli.Main(registry.Default, version)
 }

internal/script/script.go

@@ -82,6 +82,13 @@ func (cr *CaseRun) getEnvInt(name string) int {
 	return n
 }
 
+func (cr *CaseRun) Platform() interp.Platform {
+	return interp.Platform{
+		OS:   "testos",
+		Arch: "testarch",
+	}
+}
+
 func (cr *CaseRun) Stdin() interp.Input {
 	return CaseRunInput{
 		FileReader: interp.FileReader{

pkg/cli/cli.go

@@ -11,6 +11,7 @@ import (
 	"os"
 	"os/signal"
 	"path/filepath"
+	"runtime"
 
 	"github.com/wader/fq/pkg/interp"
 	"github.com/wader/fq/pkg/registry"
@@ -75,6 +76,13 @@ func newStandardOS() *stdOS {
 	}
 }
 
+func (stdOS) Platform() interp.Platform {
+	return interp.Platform{
+		OS:   runtime.GOOS,
+		Arch: runtime.GOARCH,
+	}
+}
+
 type fdTerminal uintptr
 
 func (fd fdTerminal) Size() (int, int) {
@@ -224,7 +232,7 @@ func (o *stdOS) Close() error {
 	return nil
 }
 
-func Main(r *registry.Registry, version string, osStr string, archStr string) {
+func Main(r *registry.Registry, version string) {
 	os.Exit(func() int {
 		defer maybeProfile()()
 		maybeLogFile()
@@ -238,7 +246,7 @@ func Main(r *registry.Registry, version string, osStr string, archStr string) {
 			return 1
 		}
 
-		if err := i.Main(context.Background(), sos.Stdout(), version, osStr, archStr); err != nil {
+		if err := i.Main(context.Background(), sos.Stdout(), version); err != nil {
 			if ex, ok := err.(interp.Exiter); ok { //nolint:errorlint
 				return ex.ExitCode()
 			}

pkg/fqtest/fqtest.go

@@ -41,7 +41,7 @@ func TestPath(t *testing.T, registry *registry.Registry) {
 						t.Fatal(err)
 					}
 
-					err = i.Main(context.Background(), cr.Stdout(), "testversion", "testos", "testarch")
+					err = i.Main(context.Background(), cr.Stdout(), "testversion")
 					if err != nil {
 						if ex, ok := err.(interp.Exiter); ok { //nolint:errorlint
 							cr.ActualExitCode = ex.ExitCode()

pkg/interp/interp.go

@@ -127,7 +127,13 @@ type Output interface {
 	Terminal
 }
 
+type Platform struct {
+	OS   string
+	Arch string
+}
+
 type OS interface {
+	Platform() Platform
 	Stdin() Input
 	Stdout() Output
 	Stderr() Output
@@ -359,17 +365,18 @@ func (i *Interp) Stop() {
 	i.interruptStack.Stop()
 }
 
-func (i *Interp) Main(ctx context.Context, output Output, versionStr string, osStr string, archStr string) error {
+func (i *Interp) Main(ctx context.Context, output Output, versionStr string) error {
 	var args []interface{}
 	for _, a := range i.os.Args() {
 		args = append(args, a)
 	}
 
+	platform := i.os.Platform()
 	input := map[string]interface{}{
 		"args":    args,
 		"version": versionStr,
-		"os":      osStr,
-		"arch":    archStr,
+		"os":      platform.OS,
+		"arch":    platform.Arch,
 	}
 
 	iter, err := i.EvalFunc(ctx, input, "_main", nil, output)