Add new default answer pattern for string type

Author: jmshea

README.md

@@ -233,7 +233,11 @@ Numerical questions consist of a Question, an optional Precision, and one or mor
 
 ## String Questions
 
-String questions are specified by setting the "type" property to "string". These questions offer a single question prompt that is specified by the "question" property, but may have multiple possible answers specified by the Answers array. Each Answer in the Answers array is an object that consists of an "answer" (string), a Boolean called "correct", and several optional properties. By default answers case is ignored in comparing submissions to the Answers; however, this can be changed using the boolean "match_case" property. Each answer can have a string "feedback" that is displayed when this answer is matched. Fuzzy matching can be used by specifying a value for the "fuzzy_threshold" property, which should take values between 0 and 1. Fuzzy matching calculates the Levenshtein distance, dividing that by the string length, and then subtracting the result from 1. The resulting value is 1 when the strings match exactly and decreases when the strings are more different. The schema for String Questions is shown below:
+String questions are specified by setting the "type" property to "string". These questions offer a single question prompt that is specified by the "question" property, but may have multiple possible answers specified by the Answers array. Each Answer in the Answers array is an object that consists of an "answer" (string), a Boolean called "correct", and several optional properties. By default answers case is ignored in comparing submissions to the Answers; however, this can be changed using the boolean "match_case" property. Each answer can have a string "feedback" that is displayed when this answer is matched. Fuzzy matching can be used by specifying a value for the "fuzzy_threshold" property, which should take values between 0 and 1. Fuzzy matching calculates the Levenshtein distance, dividing that by the string length, and then subtracting the result from 1. The resulting value is 1 when the strings match exactly and decreases when the strings are more different.
+
+You can optionally include a default answer pattern by specifying an object with a "type" property set to "default" and a "feedback" string. If no other answer patterns match the user's submission, the question will be marked incorrect and the provided feedback will be displayed.
+
+The schema for String Questions is shown below:
 
 ![Schema for String Questions](schema/string_schema.png)
 

jupyterquiz/__init__.py

@@ -11,5 +11,5 @@
 All files in the package are distributed under the MIT License
 '''
 
-__version__ = '2.9.5.2'
+__version__ = '2.9.6'
 from .dynamic import display_quiz, capture_responses

jupyterquiz/js/string.js

@@ -51,6 +51,17 @@ function check_string(ths, event) {
         var correct;
         var done = false;
 
+        // Handle default answer pattern: filter out and capture default feedback
+        var filteredAnswers = [];
+        answers.forEach(answer => {
+            if (answer.type === "default") {
+                defaultFB = answer.feedback;
+            } else {
+                filteredAnswers.push(answer);
+            }
+        });
+        answers = filteredAnswers;
+
         answers.every(answer => {
             correct = false;
 

schema/string_schema.json

@@ -21,29 +21,50 @@
 	          "items": { "$ref": "#/$defs/possible_answer" }
         }
     },
-        "$defs": {
+    "$defs": {
         "possible_answer": {
-            "type": "object",
-            "properties": {
-                "answer": {
-                    "type": "string"
+            "oneOf": [
+                {
+                    "type": "object",
+                    "properties": {
+                        "type": {
+                            "const": "default"
+                        },
+                        "feedback": {
+                            "type": "string"
+                        }
+                    },
+                    "required": [
+                        "type",
+                        "feedback"
+                    ],
+                    "additionalProperties": false
                 },
-                "correct": {
-                    "type": "boolean"
-                },
-                "feedback": {
-                    "type": "string"
-                },
-                "match_case": {
-                    "type": "boolean"
-                },
-                "fuzzy_threshold": {
-                    "type": "number"
+                {
+                    "type": "object",
+                    "properties": {
+                        "answer": {
+                            "type": "string"
+                        },
+                        "correct": {
+                            "type": "boolean"
+                        },
+                        "feedback": {
+                            "type": "string"
+                        },
+                        "match_case": {
+                            "type": "boolean"
+                        },
+                        "fuzzy_threshold": {
+                            "type": "number"
+                        }
+                    },
+                    "required": [
+                        "answer",
+                        "correct"
+                    ],
+                    "additionalProperties": false
                 }
-            },
-            "required": [
-                "answer",
-                "correct"
             ]
         }
     }