From 03f17af97d5f2a8b61f58f74bea206ad23446a58 Mon Sep 17 00:00:00 2001
From: Leon Mika <lmika@lmika.org>
Date: Mon, 21 Oct 2024 20:56:13 +1100
Subject: [PATCH] issue-2: added some more string functions

---
 ucl/builtins/strs.go      |  45 +++++++++++++++++
 ucl/builtins/strs_test.go | 102 ++++++++++++++++++++++++++++++++++++++
 ucl/testbuiltins_test.go  |   4 ++
 3 files changed, 151 insertions(+)
 create mode 100644 ucl/builtins/strs.go
 create mode 100644 ucl/builtins/strs_test.go

diff --git a/ucl/builtins/strs.go b/ucl/builtins/strs.go
new file mode 100644
index 0000000..33eb4e9
--- /dev/null
+++ b/ucl/builtins/strs.go
@@ -0,0 +1,45 @@
+package builtins
+
+import (
+	"context"
+	"strings"
+	"ucl.lmika.dev/ucl"
+)
+
+func Strs() ucl.Module {
+	return ucl.Module{
+		Name: "strs",
+		Builtins: map[string]ucl.BuiltinHandler{
+			"to-upper": toUpper,
+			"to-lower": toLower,
+			"trim":     trim,
+		},
+	}
+}
+
+func toUpper(ctx context.Context, args ucl.CallArgs) (any, error) {
+	var s string
+	if err := args.Bind(&s); err != nil {
+		return nil, err
+	}
+
+	return strings.ToUpper(s), nil
+}
+
+func toLower(ctx context.Context, args ucl.CallArgs) (any, error) {
+	var s string
+	if err := args.Bind(&s); err != nil {
+		return nil, err
+	}
+
+	return strings.ToLower(s), nil
+}
+
+func trim(ctx context.Context, args ucl.CallArgs) (any, error) {
+	var s string
+	if err := args.Bind(&s); err != nil {
+		return nil, err
+	}
+
+	return strings.ToLower(s), nil
+}
diff --git a/ucl/builtins/strs_test.go b/ucl/builtins/strs_test.go
new file mode 100644
index 0000000..c6ef90a
--- /dev/null
+++ b/ucl/builtins/strs_test.go
@@ -0,0 +1,102 @@
+package builtins_test
+
+import (
+	"context"
+	"github.com/stretchr/testify/assert"
+	"testing"
+	"ucl.lmika.dev/ucl"
+	"ucl.lmika.dev/ucl/builtins"
+)
+
+func TestStrs_ToUpper(t *testing.T) {
+	tests := []struct {
+		desc    string
+		eval    string
+		want    any
+		wantErr bool
+	}{
+		{desc: "to upper 1", eval: `strs:to-upper "hello"`, want: "HELLO"},
+		{desc: "to upper 2", eval: `strs:to-upper ""`, want: ""},
+		{desc: "to upper 3", eval: `strs:to-upper 123`, want: "123"},
+		{desc: "to upper 4", eval: `strs:to-upper "foo Bar BaZ"`, want: "FOO BAR BAZ"},
+
+		{desc: "err to upper 1", eval: `strs:to-upper`, wantErr: true},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.desc, func(t *testing.T) {
+			inst := ucl.New(
+				ucl.WithModule(builtins.Strs()),
+			)
+			res, err := inst.Eval(context.Background(), tt.eval)
+			if tt.wantErr {
+				assert.Error(t, err)
+			} else {
+				assert.NoError(t, err)
+				assert.Equal(t, tt.want, res)
+			}
+		})
+	}
+}
+
+func TestStrs_ToLower(t *testing.T) {
+	tests := []struct {
+		desc    string
+		eval    string
+		want    any
+		wantErr bool
+	}{
+		{desc: "to lower 1", eval: `strs:to-lower "HeLLo"`, want: "hello"},
+		{desc: "to lower 2", eval: `strs:to-lower ""`, want: ""},
+		{desc: "to lower 3", eval: `strs:to-lower 123`, want: "123"},
+		{desc: "to lower 4", eval: `strs:to-lower "foo Bar BaZ"`, want: "foo bar baz"},
+
+		{desc: "err to lower 1", eval: `strs:to-lower`, wantErr: true},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.desc, func(t *testing.T) {
+			inst := ucl.New(
+				ucl.WithModule(builtins.Strs()),
+			)
+			res, err := inst.Eval(context.Background(), tt.eval)
+			if tt.wantErr {
+				assert.Error(t, err)
+			} else {
+				assert.NoError(t, err)
+				assert.Equal(t, tt.want, res)
+			}
+		})
+	}
+}
+
+func TestStrs_Trim(t *testing.T) {
+	tests := []struct {
+		desc    string
+		eval    string
+		want    any
+		wantErr bool
+	}{
+		{desc: "trim space 1", eval: `strs:trim "  hello   "`, want: "hello"},
+		{desc: "trim space 2", eval: `strs:trim ""`, want: ""},
+		{desc: "trim space 3", eval: `strs:trim "   123"`, want: "123"},
+		{desc: "trim space 4", eval: `strs:trim "foo Bar BaZ    "`, want: "foo Bar BaZ"},
+
+		{desc: "err trim space 1", eval: `strs:trim`, wantErr: true},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.desc, func(t *testing.T) {
+			inst := ucl.New(
+				ucl.WithModule(builtins.Strs()),
+			)
+			res, err := inst.Eval(context.Background(), tt.eval)
+			if tt.wantErr {
+				assert.Error(t, err)
+			} else {
+				assert.NoError(t, err)
+				assert.Equal(t, tt.want, res)
+			}
+		})
+	}
+}
diff --git a/ucl/testbuiltins_test.go b/ucl/testbuiltins_test.go
index 7d0ae1c..3e6c68a 100644
--- a/ucl/testbuiltins_test.go
+++ b/ucl/testbuiltins_test.go
@@ -17,6 +17,10 @@ func WithTestBuiltin() InstOption {
 			return args.args[0], nil
 		}))
 
+		i.rootEC.addCmd("toUpper", invokableFunc(func(ctx context.Context, args invocationArgs) (object, error) {
+			return strObject(strings.ToUpper(args.args[0].String())), nil
+		}))
+
 		i.rootEC.addCmd("sjoin", invokableFunc(func(ctx context.Context, args invocationArgs) (object, error) {
 			if len(args.args) == 0 {
 				return strObject(""), nil