From 8c5cb299c2ce2a2ac4c7f905e1e68820b65ac596 Mon Sep 17 00:00:00 2001
From: Leon Mika <lmika@lmika.org>
Date: Wed, 11 Dec 2024 20:47:05 +1100
Subject: [PATCH] Started working on a REPL helper

---
 cmd/cmsh/main.go    |  3 ++-
 repl/docs.go        |  6 +++++
 repl/evaldisplay.go | 37 ++++++++++++++++++++++++++
 repl/repl.go        | 64 +++++++++++++++++++++++++++++++++++++++++++++
 ucl/evaldisplay.go  | 35 -------------------------
 ucl/inst.go         |  2 +-
 6 files changed, 110 insertions(+), 37 deletions(-)
 create mode 100644 repl/docs.go
 create mode 100644 repl/evaldisplay.go
 create mode 100644 repl/repl.go
 delete mode 100644 ucl/evaldisplay.go

diff --git a/cmd/cmsh/main.go b/cmd/cmsh/main.go
index afd1ba5..1688d2d 100644
--- a/cmd/cmsh/main.go
+++ b/cmd/cmsh/main.go
@@ -4,6 +4,7 @@ import (
 	"context"
 	"github.com/chzyer/readline"
 	"log"
+	"ucl.lmika.dev/repl"
 	"ucl.lmika.dev/ucl"
 	"ucl.lmika.dev/ucl/builtins"
 )
@@ -15,7 +16,7 @@ func main() {
 	}
 	defer rl.Close()
 
-	inst := ucl.New(
+	instRepl := repl.New(
 		ucl.WithModule(builtins.OS()),
 		ucl.WithModule(builtins.FS(nil)),
 	)
diff --git a/repl/docs.go b/repl/docs.go
new file mode 100644
index 0000000..a8ba0e4
--- /dev/null
+++ b/repl/docs.go
@@ -0,0 +1,6 @@
+package repl
+
+type Doc struct {
+	Brief    string
+	Detailed string
+}
diff --git a/repl/evaldisplay.go b/repl/evaldisplay.go
new file mode 100644
index 0000000..c8704ec
--- /dev/null
+++ b/repl/evaldisplay.go
@@ -0,0 +1,37 @@
+package repl
+
+import (
+	"context"
+	"fmt"
+	"os"
+	"ucl.lmika.dev/ucl"
+)
+
+func (r *REPL) EvalAndDisplay(ctx context.Context, expr string) error {
+	res, err := r.inst.Eval(ctx, expr)
+	if err != nil {
+		return err
+	}
+
+	return displayResult(ctx, r.inst, res)
+}
+
+func displayResult(ctx context.Context, inst *ucl.Inst, res any) (err error) {
+	switch v := res.(type) {
+	case nil:
+		if _, err = fmt.Fprintln(os.Stdout, "(nil)"); err != nil {
+			return err
+		}
+	case listable:
+		for i := 0; i < v.Len(); i++ {
+			if err = displayResult(ctx, inst, v.Index(i)); err != nil {
+				return err
+			}
+		}
+	default:
+		if _, err = fmt.Fprintln(os.Stdout, v.String()); err != nil {
+			return err
+		}
+	}
+	return nil
+}
diff --git a/repl/repl.go b/repl/repl.go
new file mode 100644
index 0000000..ec872c1
--- /dev/null
+++ b/repl/repl.go
@@ -0,0 +1,64 @@
+package repl
+
+import (
+	"context"
+	"fmt"
+	"github.com/lmika/gopkgs/fp/maps"
+	"sort"
+	"ucl.lmika.dev/ucl"
+)
+
+type CommandOpt interface {
+	config(cmdName string, r *REPL)
+}
+
+type REPL struct {
+	inst *ucl.Inst
+
+	commandDocs map[string]Doc
+}
+
+func New(opts ...ucl.InstOption) *REPL {
+	inst := ucl.New(opts...)
+
+	r := &REPL{
+		inst:        inst,
+		commandDocs: make(map[string]Doc),
+	}
+	inst.SetBuiltin("help", r.helpBuiltin)
+
+	return r
+}
+
+func (r *REPL) Inst() *ucl.Inst {
+	return r.inst
+}
+
+func (r *REPL) SetCommand(name string, fn ucl.BuiltinHandler, opts ...CommandOpt) {
+	r.commandDocs[name] = Doc{}
+	for _, opt := range opts {
+		opt.config(name, r)
+	}
+
+	r.inst.SetBuiltin(name, fn)
+}
+
+func (r *REPL) helpBuiltin(ctx context.Context, args ucl.CallArgs) (any, error) {
+	switch {
+	case args.NArgs() == 0:
+		// TEMP
+		names := maps.Keys(r.commandDocs)
+		sort.Strings(names)
+
+		for _, name := range names {
+			cdoc := r.commandDocs[name]
+			if cdoc.Brief != "" {
+				fmt.Println("%v\t%v", name, r.commandDocs[name])
+			} else {
+				fmt.Println("%v", name)
+			}
+		}
+		// END TEMP
+	}
+	return nil, nil
+}
diff --git a/ucl/evaldisplay.go b/ucl/evaldisplay.go
deleted file mode 100644
index b73fe87..0000000
--- a/ucl/evaldisplay.go
+++ /dev/null
@@ -1,35 +0,0 @@
-package ucl
-
-import (
-	"context"
-	"fmt"
-)
-
-func EvalAndDisplay(ctx context.Context, inst *Inst, expr string) error {
-	res, err := inst.eval(ctx, expr)
-	if err != nil {
-		return err
-	}
-
-	return displayResult(ctx, inst, res)
-}
-
-func displayResult(ctx context.Context, inst *Inst, res Object) (err error) {
-	switch v := res.(type) {
-	case nil:
-		if _, err = fmt.Fprintln(inst.out, "(nil)"); err != nil {
-			return err
-		}
-	case Listable:
-		for i := 0; i < v.Len(); i++ {
-			if err = displayResult(ctx, inst, v.Index(i)); err != nil {
-				return err
-			}
-		}
-	default:
-		if _, err = fmt.Fprintln(inst.out, v.String()); err != nil {
-			return err
-		}
-	}
-	return nil
-}
diff --git a/ucl/inst.go b/ucl/inst.go
index 07b316c..f1c9b19 100644
--- a/ucl/inst.go
+++ b/ucl/inst.go
@@ -47,7 +47,7 @@ func New(opts ...InstOption) *Inst {
 	rootEC.root = rootEC
 
 	rootEC.addCmd("echo", invokableFunc(echoBuiltin))
-	rootEC.addCmd("set", invokableFunc(setBuiltin))
+	rootEC.addCmd("var", invokableFunc(setBuiltin))
 	rootEC.addCmd("toUpper", invokableFunc(toUpperBuiltin))
 	rootEC.addCmd("len", invokableFunc(lenBuiltin))
 	rootEC.addCmd("keys", invokableFunc(keysBuiltin))