implement ltrim, rtrim, and trim functions

cli/test.yaml

@@ -2082,6 +2082,63 @@
     "rtrimstr({}) cannot be applied to: string (\"x\")"
     "rtrimstr(\"x\") cannot be applied to: number (10)"
 
+- name: ltrim function
+  args:
+    - 'ltrim'
+  input: |
+    ""
+    "  \tfoo\n  "
+    "\t\u000b\u000c\u0085\u00a0f\ro\no\u2000\u2001\u200a\u3000"
+  expected: "\"\"\n\"foo\\n  \"\n\"f\\ro\\no\u2000\u2001\u200a\u3000\"\n"
+
+- name: ltrim function error
+  args:
+    - 'try ltrim catch .'
+  input: '0 [] {}'
+  expected: |
+    "ltrim cannot be applied to: number (0)"
+    "ltrim cannot be applied to: array ([])"
+    "ltrim cannot be applied to: object ({})"
+
+- name: rtrim function
+  args:
+    - 'rtrim'
+  input: |
+    ""
+    "  \tfoo\n  "
+    "\t\u000b\u000c\u0085\u00a0f\ro\no\u2000\u2001\u200a\u3000"
+  expected: "\"\"\n\"  \\tfoo\"\n\"\\t\\u000b\\f\u0085\u00a0f\\ro\\no\"\n"
+
+- name: rtrim function error
+  args:
+    - 'try rtrim catch .'
+  input: '0 [] {}'
+  expected: |
+    "rtrim cannot be applied to: number (0)"
+    "rtrim cannot be applied to: array ([])"
+    "rtrim cannot be applied to: object ({})"
+
+- name: trim function
+  args:
+    - 'trim'
+  input: |
+    ""
+    "  \tfoo\n  "
+    "\t\u000b\u000c\u0085\u00a0f\ro\no\u2000\u2001\u200a\u3000"
+  expected: |
+    ""
+    "foo"
+    "f\ro\no"
+
+- name: trim function error
+  args:
+    - 'try trim catch .'
+  input: '0 [] {}'
+  expected: |
+    "trim cannot be applied to: number (0)"
+    "trim cannot be applied to: array ([])"
+    "trim cannot be applied to: object ({})"
+
 - name: explode function
   args:
     - -c

func.go

@@ -15,6 +15,7 @@ import (
 	"strconv"
 	"strings"
 	"time"
+	"unicode"
 	"unicode/utf8"
 
 	"github.com/itchyny/timefmt-go"
@@ -70,6 +71,9 @@ func init() {
 		"endswith":       argFunc1(funcEndsWith),
 		"ltrimstr":       argFunc1(funcLtrimstr),
 		"rtrimstr":       argFunc1(funcRtrimstr),
+		"ltrim":          argFunc0(funcLtrim),
+		"rtrim":          argFunc0(funcRtrim),
+		"trim":           argFunc0(funcTrim),
 		"explode":        argFunc0(funcExplode),
 		"implode":        argFunc0(funcImplode),
 		"split":          {argcount1 | argcount2, false, funcSplit},
@@ -702,6 +706,30 @@ func funcRtrimstr(v, x any) any {
 	return strings.TrimSuffix(s, t)
 }
 
+func funcLtrim(v any) any {
+	s, ok := v.(string)
+	if !ok {
+		return &func0TypeError{"ltrim", v}
+	}
+	return strings.TrimLeftFunc(s, unicode.IsSpace)
+}
+
+func funcRtrim(v any) any {
+	s, ok := v.(string)
+	if !ok {
+		return &func0TypeError{"rtrim", v}
+	}
+	return strings.TrimRightFunc(s, unicode.IsSpace)
+}
+
+func funcTrim(v any) any {
+	s, ok := v.(string)
+	if !ok {
+		return &func0TypeError{"trim", v}
+	}
+	return strings.TrimSpace(s)
+}
+
 func funcExplode(v any) any {
 	s, ok := v.(string)
 	if !ok {