Port parsing of env instructions

tools/cmd/ssh/config.go

@@ -4,20 +4,43 @@ package ssh
 
 import (
 	"fmt"
+	"strings"
 )
 
 var _ = fmt.Print
 
 type EnvInstruction struct {
+	key, val                          string
+	delete_on_remote, copy_from_local bool
 }
 
 type CopyInstruction struct {
+	local_path, arcname string
+	exclude_patterns    []string
 }
 
 func NewEnvInstruction(spec string) (ei *EnvInstruction, err error) {
+	const COPY_FROM_LOCAL string = "_kitty_copy_env_var_"
+	ei = &EnvInstruction{}
+	found := false
+	ei.key, ei.val, found = strings.Cut(spec, "=")
+	ei.key = strings.TrimSpace(ei.key)
+	if found {
+		ei.val = strings.TrimSpace(ei.val)
+		if ei.val == COPY_FROM_LOCAL {
+			ei.val = ""
+			ei.copy_from_local = true
+		}
+	} else {
+		ei.delete_on_remote = true
+	}
+	if ei.key == "" {
+		err = fmt.Errorf("The env directive must not be empty")
+	}
 	return
 }
 
 func NewCopyInstruction(spec string) (ci *CopyInstruction, err error) {
+	ci = &CopyInstruction{}
 	return
 }