Added new function support microsoft#1227

docs/CHANGELOG-v2.md

@@ -35,6 +35,9 @@ What's changed since pre-release v2.7.0-B0016:
 - New features:
   - Added API version date comparison assertion method and expression by @BernieWhite.
     [#1356](https://github.com/microsoft/PSRule/issues/1356)
+  - Added support for new functions by @BernieWhite.
+    [#1227](https://github.com/microsoft/PSRule/issues/1227)
+    - Added support for `trim`, `replace`, `split`, `first`, and `last`.
 - Bug fixes:
   - Fixes CLI failed to load required assemblies by @BernieWhite.
     [#1361](https://github.com/microsoft/PSRule/issues/1361)

docs/expressions/functions.md

@@ -22,12 +22,17 @@ Functions cover two (2) main scenarios:
 It may be necessary to perform minor transformation before evaluating a condition.
 
 - `boolean` - Convert a value to a boolean.
-- `string` - Convert a value to a string.
-- `integer` - Convert a value to an integer.
 - `concat` - Concatenate multiple values.
-- `substring` - Extract a substring from a string.
 - `configuration` - Get a configuration value.
+- `first` - Return the first element in an array or the first character of a string.
+- `integer` - Convert a value to an integer.
+- `last` - Return the last element in an array or the last character of a string.
 - `path` - Get a value from an object path.
+- `replace` - Replace an old string with a new string.
+- `split` - Split a string into an array by a delimiter.
+- `string` - Convert a value to a string.
+- `substring` - Extract a substring from a string.
+- `trim` - Remove whitespace from the start and end of a string.
 
 ## Supported conditions
 

schemas/PSRule-language.schema.json

@@ -3034,6 +3034,21 @@
             },
             {
               "$ref": "#/definitions/fn/definitions/function/definitions/configuration"
+            },
+            {
+              "$ref": "#/definitions/fn/definitions/function/definitions/replace"
+            },
+            {
+              "$ref": "#/definitions/fn/definitions/function/definitions/trim"
+            },
+            {
+              "$ref": "#/definitions/fn/definitions/function/definitions/first"
+            },
+            {
+              "$ref": "#/definitions/fn/definitions/function/definitions/last"
+            },
+            {
+              "$ref": "#/definitions/fn/definitions/function/definitions/split"
             }
           ],
           "definitions": {
@@ -3305,6 +3320,159 @@
               "required": [
                 "configuration"
               ]
+            },
+            "replace": {
+              "type": "object",
+              "properties": {
+                "replace": {
+                  "type": "object",
+                  "title": "Trim",
+                  "description": "The replace function searches for a string and replaces them with a new string.",
+                  "markdownDescription": "The `replace` function searches for a string and replaces them with a new string.",
+                  "$ref": "#/definitions/fn/definitions/function"
+                },
+                "oldString": {
+                  "type": "string",
+                  "description": "The string to replace.",
+                  "minLength": 1
+                },
+                "newString": {
+                  "type": "string",
+                  "description": "The new string to replace oldString."
+                },
+                "caseSensitive": {
+                  "type": "boolean",
+                  "title": "Case-sensitive",
+                  "description": "Determines if the replace is case-sensitive. By default, a case-insensitive comparison is performed.",
+                  "default": false
+                }
+              },
+              "additionalProperties": false,
+              "required": [
+                "replace",
+                "oldString",
+                "newString"
+              ]
+            },
+            "trim": {
+              "type": "object",
+              "properties": {
+                "trim": {
+                  "type": "object",
+                  "title": "Trim",
+                  "description": "Trim a string value by removing leading and trailings whitespace.",
+                  "markdownDescription": "Trim a string value by removing leading and trailings whitespace.",
+                  "$ref": "#/definitions/fn/definitions/function"
+                }
+              },
+              "additionalProperties": false,
+              "required": [
+                "trim"
+              ]
+            },
+            "first": {
+              "type": "object",
+              "properties": {
+                "first": {
+                  "oneOf": [
+                    {
+                      "type": "array",
+                      "description": "The first function returns the first element in the array.",
+                      "markdownDescription": "The `first` function returns the first element in the array.",
+                      "items": {
+                        "$ref": "#/definitions/fn/definitions/function"
+                      },
+                      "additionalItems": false,
+                      "minItems": 2
+                    },
+                    {
+                      "type": "object",
+                      "description": "The first function returns the first element of arrays or the first character of a string.",
+                      "markdownDescription": "The `first` function returns the first element of arrays or the first character of a string.",
+                      "$ref": "#/definitions/fn/definitions/function"
+                    }
+                  ]
+                }
+              },
+              "additionalProperties": false,
+              "required": [
+                "first"
+              ]
+            },
+            "last": {
+              "type": "object",
+              "properties": {
+                "last": {
+                  "oneOf": [
+                    {
+                      "type": "array",
+                      "description": "The last function returns the last element in the array.",
+                      "markdownDescription": "The `last` function returns the last element in the array.",
+                      "items": {
+                        "$ref": "#/definitions/fn/definitions/function"
+                      },
+                      "additionalItems": false,
+                      "minItems": 2
+                    },
+                    {
+                      "type": "object",
+                      "description": "The last function returns the last element of arrays or the last character of a string.",
+                      "markdownDescription": "The `last` function returns the last element of arrays or the last character of a string.",
+                      "$ref": "#/definitions/fn/definitions/function"
+                    }
+                  ]
+                }
+              },
+              "additionalProperties": false,
+              "required": [
+                "last"
+              ]
+            },
+            "split": {
+              "type": "object",
+              "properties": {
+                "split": {
+                  "oneOf": [
+                    {
+                      "type": "string",
+                      "description": "The split function returns converts a string into an array by spliting based on a delimiter.",
+                      "markdownDescription": "The `split` function returns converts a string into an array by spliting based on a delimiter."
+                    },
+                    {
+                      "type": "object",
+                      "description": "The split function returns converts a string into an array by spliting based on a delimiter.",
+                      "markdownDescription": "The `split` function returns converts a string into an array by spliting based on a delimiter.",
+                      "$ref": "#/definitions/fn/definitions/function"
+                    }
+                  ],
+                  "default": {}
+                },
+                "delimiter": {
+                  "oneOf": [
+                    {
+                      "type": "string",
+                      "minLength": 1
+                    },
+                    {
+                      "type": "array",
+                      "items": {
+                        "type": "string",
+                        "minLength": 1
+                      },
+                      "minItems": 1,
+                      "additionalItems": false
+                    }
+                  ],
+                  "default": [
+                    ""
+                  ]
+                }
+              },
+              "additionalProperties": false,
+              "required": [
+                "split",
+                "delimiter"
+              ]
             }
           }
         }

src/PSRule/Common/ArrayExtensions.cs

@@ -0,0 +1,23 @@
+// Copyright (c) Microsoft Corporation.
+// Licensed under the MIT License.
+
+using System;
+
+namespace PSRule.Common
+{
+    /// <summary>
+    /// Extension methods for arrays.
+    /// </summary>
+    internal static class ArrayExtensions
+    {
+        internal static object Last(this Array array)
+        {
+            return array.Length > 0 ? array.GetValue(array.Length - 1) : null;
+        }
+
+        internal static object First(this Array array)
+        {
+            return array.Length > 0 ? array.GetValue(0) : null;
+        }
+    }
+}

src/PSRule/Common/ExpressionHelpers.cs

@@ -7,6 +7,7 @@
 using System.IO;
 using System.Linq;
 using System.Management.Automation;
+using System.Reflection;
 using System.Text.RegularExpressions;
 using System.Threading;
 using Newtonsoft.Json.Linq;
@@ -57,6 +58,9 @@ internal static bool Equal(object expectedValue, object actualValue, bool caseSe
             if (TryInt(expectedValue, convertExpected, out var i1) && TryInt(actualValue, convertActual, out var i2))
                 return i1 == i2;
 
+            if (TryArray(expectedValue, out var a1) && TryArray(actualValue, out var a2))
+                return SequenceEqual(a1, a2);
+
             var expectedBase = GetBaseObject(expectedValue);
             var actualBase = GetBaseObject(actualValue);
             if (expectedBase == null || actualBase == null)
@@ -65,6 +69,69 @@ internal static bool Equal(object expectedValue, object actualValue, bool caseSe
             return expectedBase.Equals(actualBase) || expectedValue.Equals(actualValue);
         }
 
+        internal static bool SequenceEqual(Array array1, Array array2)
+        {
+            if (array1.Length != array2.Length)
+                return false;
+
+            for (var i = 0; i < array1.Length; i++)
+            {
+                if (!Equal(array1.GetValue(i), array2.GetValue(i)))
+                    return false;
+            }
+            return true;
+        }
+
+        internal static bool Equal(object o1, object o2)
+        {
+            // One null
+            if (o1 == null || o2 == null)
+                return o1 == o2;
+
+            // Arrays
+            if (o1 is Array array1 && o2 is Array array2)
+                return SequenceEqual(array1, array2);
+            else if (o1 is Array || o2 is Array)
+                return false;
+
+            // String and int
+            if (TryString(o1, out var s1) && TryString(o2, out var s2))
+                return s1 == s2;
+            else if (TryString(o1, out _) || TryString(o2, out _))
+                return false;
+            else if (TryLong(o1, false, out var i1) && TryLong(o2, false, out var i2))
+                return i1 == i2;
+            else if (TryLong(o1, false, out var _) || TryLong(o2, false, out var _))
+                return false;
+
+            // JTokens
+            if (o1 is JToken t1 && o2 is JToken t2)
+                return JTokenEquals(t1, t2);
+
+            // Objects
+            return ObjectEquals(o1, o2);
+        }
+
+        private static bool JTokenEquals(JToken t1, JToken t2)
+        {
+            return JToken.DeepEquals(t1, t2);
+        }
+
+        internal static bool ObjectEquals(object o1, object o2)
+        {
+            var objectType = o1.GetType();
+            if (objectType != o2.GetType())
+                return false;
+
+            var props = objectType.GetProperties(BindingFlags.Public | BindingFlags.Instance | BindingFlags.GetProperty);
+            for (var i = 0; i < props.Length; i++)
+            {
+                if (!object.Equals(props[i].GetValue(o1), props[i].GetValue(o2)))
+                    return false;
+            }
+            return true;
+        }
+
         internal static int Compare(object left, object right)
         {
             if (TryString(left, out var stringLeft) && TryString(right, out var stringRight))
@@ -162,13 +229,18 @@ internal static bool TryString(object o, bool convert, out string value)
         internal static bool TryArray(object o, out Array value)
         {
             o = GetBaseObject(o);
+            value = null;
+            if (o is string) return false;
             if (o is Array a)
-            {
                 value = a;
-                return true;
-            }
-            value = null;
-            return false;
+
+            else if (o is JArray jArray)
+                value = jArray.Values<object>().ToArray();
+
+            else if (o is IEnumerable e)
+                value = e.OfType<object>().ToArray();
+
+            return value != null;
         }
 
         internal static bool TryConvertStringArray(object o, out string[] value)

src/PSRule/Common/StringExtensions.cs

@@ -1,8 +1,9 @@
-// Copyright (c) Microsoft Corporation.
+// Copyright (c) Microsoft Corporation.
 // Licensed under the MIT License.
 
 using System;
 using System.Collections.Generic;
+using System.Text;
 
 namespace PSRule
 {
@@ -78,5 +79,31 @@ public static bool Contains(this string source, string value, StringComparison c
         {
             return source?.IndexOf(value, comparison) >= 0;
         }
+
+        public static string Replace(this string s, string oldString, string newString, bool caseSensitive)
+        {
+            if (string.IsNullOrEmpty(s) || string.IsNullOrEmpty(oldString) || s.Length < oldString.Length)
+                return s;
+
+            if (caseSensitive)
+                return s.Replace(oldString, newString);
+
+            var sb = new StringBuilder(s.Length);
+            var pos = 0;
+            var replaceWithEmpty = string.IsNullOrEmpty(newString);
+            int indexAt;
+            while ((indexAt = s.IndexOf(oldString, pos, StringComparison.OrdinalIgnoreCase)) != -1)
+            {
+                sb.Append(s, pos, indexAt - pos);
+                if (!replaceWithEmpty)
+                    sb.Append(newString);
+
+                pos = indexAt + oldString.Length;
+            }
+            if (pos < s.Length)
+                sb.Append(s, pos, s.Length - pos);
+
+            return sb.ToString();
+        }
     }
 }