Docs: add validators API

include/tcframe/validator/core.hpp

@@ -38,23 +38,23 @@ inline ScalarValidator<T> valueOf(T val) {
 template<typename T, typename = ScalarType<T>>
 struct VectorElementValidator {
 private:
-    const vector<T>& val;
+    const vector<T>& vec;
 
 public:
-    explicit VectorElementValidator(const vector<T>& _val) : val(_val) {}
+    explicit VectorElementValidator(const vector<T>& _vec) : vec(_vec) {}
 
     bool isBetween(T minVal, T maxVal) {
-        for (T v : val) {
-            if (!valueOf(v).isBetween(minVal, maxVal)) {
+        for (T e : vec) {
+            if (!valueOf(e).isBetween(minVal, maxVal)) {
                 return false;
             }
         }
         return true;
     }
 
     bool satisfies(function<bool(T)> predicate) {
-        for (T v : val) {
-            if (!predicate(v)) {
+        for (T e : vec) {
+            if (!predicate(e)) {
                 return false;
             }
         }
@@ -63,98 +63,98 @@ struct VectorElementValidator {
 };
 
 template<typename T, typename = ScalarType<T>>
-inline VectorElementValidator<T> eachElementOf(const vector<T>& val) {
-    return VectorElementValidator(val);
+inline VectorElementValidator<T> eachElementOf(const vector<T>& vec) {
+    return VectorElementValidator(vec);
 }
 
 template<typename T, typename = ScalarType<T>>
 struct VectorElementsValidator {
 private:
-    const vector<T>& val;
+    const vector<T>& vec;
 
 public:
-    explicit VectorElementsValidator(const vector<T>& _val) : val(_val) {}
+    explicit VectorElementsValidator(const vector<T>& _vec) : vec(_vec) {}
 
     bool areAscending() {
-        for (size_t i = 1; i < val.size(); ++i) {
-            if (val[i - 1] >= val[i]) {
+        for (size_t i = 1; i < vec.size(); ++i) {
+            if (vec[i - 1] >= vec[i]) {
                 return false;
             }
         }
         return true;
     }
 
     bool areDescending() {
-        for (size_t i = 1; i < val.size(); ++i) {
-            if (val[i - 1] <= val[i]) {
+        for (size_t i = 1; i < vec.size(); ++i) {
+            if (vec[i - 1] <= vec[i]) {
                 return false;
             }
         }
         return true;
     }
 
     bool areNonAscending() {
-        for (size_t i = 1; i < val.size(); ++i) {
-            if (val[i - 1] < val[i]) {
+        for (size_t i = 1; i < vec.size(); ++i) {
+            if (vec[i - 1] < vec[i]) {
                 return false;
             }
         }
         return true;
     }
 
     bool areNonDescending() {
-        for (size_t i = 1; i < val.size(); ++i) {
-            if (val[i - 1] > val[i]) {
+        for (size_t i = 1; i < vec.size(); ++i) {
+            if (vec[i - 1] > vec[i]) {
                 return false;
             }
         }
         return true;
     }
 
     bool areUnique() {
-        vector<T> v = val;
+        vector<T> v = vec;
         sort(v.begin(), v.end());
         size_t ns = unique(v.begin(), v.end()) - v.begin();
         return ns == v.size();
     }
 };
 
 template<typename T, typename = ScalarType<T>>
-inline VectorElementsValidator<T> elementsOf(const vector<T>& val) {
-    return VectorElementsValidator(val);
+inline VectorElementsValidator<T> elementsOf(const vector<T>& vec) {
+    return VectorElementsValidator(vec);
 }
 
 struct StringElementValidator {
 private:
-    const string& val;
+    const string& str;
 
 public:
-    explicit StringElementValidator(const string& _val) : val(_val) {}
+    explicit StringElementValidator(const string& _str) : str(_str) {}
 
     bool isBetween(char minVal, char maxVal) {
-        for (char v : val) {
-            if (!valueOf(v).isBetween(minVal, maxVal)) {
+        for (char c : str) {
+            if (!valueOf(c).isBetween(minVal, maxVal)) {
                 return false;
             }
         }
         return true;
     }
 };
 
-inline StringElementValidator eachCharacterOf(const string& val) {
-    return StringElementValidator(val);
+inline StringElementValidator eachCharacterOf(const string& str) {
+    return StringElementValidator(str);
 }
 
 template<typename T, typename = ScalarType<T>>
 struct MatrixElementValidator {
 private:
-    const vector<vector<T>>& val;
+    const vector<vector<T>>& mat;
 
 public:
-    explicit MatrixElementValidator(const vector<vector<T>>& _val) : val(_val) {}
+    explicit MatrixElementValidator(const vector<vector<T>>& _mat) : mat(_mat) {}
 
     bool isBetween(T minVal, T maxVal) {
-        for (const vector<T>& v : val) {
+        for (const vector<T>& v : mat) {
             if (!eachElementOf(v).isBetween(minVal, maxVal)) {
                 return false;
             }
@@ -163,7 +163,7 @@ struct MatrixElementValidator {
     }
 
     bool satisfies(function<bool(T)> predicate) {
-        for (const vector<T>& v : val) {
+        for (const vector<T>& v : mat) {
             if (!eachElementOf(v).satisfies(predicate)) {
                 return false;
             }
@@ -173,8 +173,8 @@ struct MatrixElementValidator {
 };
 
 template<typename T, typename = ScalarType<T>>
-inline MatrixElementValidator<T> eachElementOf(const vector<vector<T>>& val) {
-    return MatrixElementValidator(val);
+inline MatrixElementValidator<T> eachElementOf(const vector<vector<T>>& mat) {
+    return MatrixElementValidator(mat);
 }
 
 }

web/docs/api/04-validators/01-core.md

@@ -0,0 +1,174 @@
+---
+toc_max_heading_level: 4
+---
+
+# Core validators
+
+## Validating a scalar value
+
+A scalar type is defined as:
+
+```cpp
+template<typename T>
+using ScalarType = std::enable_if_t<std::is_arithmetic_v<T>>;
+```
+
+Or in simple words, it includes `int`, `long long`, `double`, and `char`.
+
+To instantiate the validator for a value, say `val`, call the following function:
+
+### `valueOf(val)`
+
+```cpp
+template<typename T, typename = ScalarType<T>>
+ScalarValidator<T> valueOf(T val);
+```
+
+This validator contains the following function:
+
+#### `.isBetween()`
+
+```cpp
+bool ScalarValidator<T>::isBetween(T minVal, T maxVal);
+```
+
+Returns whether `val` is between `minVal` and `maxVal`, inclusive.
+
+---
+
+## Validating each element of a vector
+
+To instantiate the validator for a each element of a vector, say `vec`, call the following function:
+
+### `eachElementOf(vec)`
+
+```cpp
+template<typename T, typename = ScalarType<T>>
+VectorElementValidator<T> eachElementOf(const std::vector<T>& vec);
+```
+
+This validator contains the following functions:
+
+#### `.isBetween()`
+
+```cpp
+bool VectorElementValidator<T>::isBetween(T minVal, T maxVal);
+```
+
+Returns whether each element of `vec` is between `minVal` and `maxVal`, inclusive.
+
+#### `.satisfies()`
+
+```cpp
+bool VectorElementValidator<T>::satisfies(std::function<bool(T)> predicate);
+```
+
+Returns whether `predicate(e)` returns true for each `e` element of `vec`.
+
+---
+
+## Validating each element of a matrix
+
+To instantiate the validator for a each element of a matrix, say `mat`, call the following function:
+
+### `eachElementOf(mat)`
+
+```cpp
+template<typename T, typename = ScalarType<T>>
+MatrixElementValidator<T> eachElementOf(const std::vector<std::vector<T>>& mat);
+```
+
+This validator contains the following functions:
+
+#### `.isBetween()`
+
+```cpp
+bool MatrixElementValidator<T>::isBetween(T minVal, T maxVal);
+```
+
+Returns whether each element of `mat` is between `minVal` and `maxVal`, inclusive.
+
+#### `.satisfies()`
+
+```cpp
+bool MatrixElementValidator<T>::satisfies(std::function<bool(T)> predicate);
+```
+
+Returns whether `predicate(e)` returns true for each `e` element of `mat`.
+
+---
+
+## Validating each character of a string
+
+To instantiate the validator for a each character of a string, say `str`, call the following function:
+
+### `eachCharacterOf(str)`
+
+```cpp
+StringElementValidator eachCharacterOf(const std::string& str);
+```
+
+This validator contains the following functions:
+
+#### `.isBetween()`
+
+```cpp
+bool StringElementValidator::isBetween(char minVal, char maxVal);
+```
+
+Returns whether each character of `str` is between `minVal` and `maxVal`, inclusive.
+
+---
+
+## Validating all elements of a vector
+
+To instantiate the validator for all elements of a vector, say `vec`, call the following function:
+
+### `elementsOf(vec)`
+
+```cpp
+template<typename T, typename = ScalarType<T>>
+VectorElementsValidator<T> elementsOf(const std::vector<T>& vec);
+```
+
+This validator contains the following functions:
+
+#### `.areAscending()`
+
+```cpp
+bool VectorElementsValidator<T>::areAscending();
+```
+
+Returns whether the elements of `vec` are in a strictly ascending order.
+
+#### `.areDescending()`
+
+```cpp
+bool VectorElementsValidator<T>::areDescending();
+```
+
+Returns whether the elements of `vec` are in a strictly descending order.
+
+#### `.areNonAscending()`
+
+```cpp
+bool VectorElementsValidator<T>::areNonAscending();
+```
+
+Returns whether the elements of `vec` are in a non-ascending order.
+
+#### `.areNonDescending()`
+
+```cpp
+bool VectorElementsValidator<T>::areNonDescending();
+```
+
+Returns whether the elements of `vec` are in a non-descending order.
+
+#### `.areUnique()`
+
+```cpp
+bool VectorElementsValidator<T>::areUnique();
+```
+
+Returns whether the elements of `vec` are unique (all different).

web/docs/api/04-validators/_category_.yml

@@ -0,0 +1,5 @@
+label: Validators
+link: 
+  type: generated-index
+  slug: /api/validators
+  description: TCFrame provides several validators, which can be used to validate the I/O variables in problem spec.

web/docs/topic-guides/05-constraints.md

@@ -24,7 +24,11 @@ void Constraints() {
 }
 ```
 
-The constraint definition can be pulled directly from the constraints section in the actual problem description. For example: "1 ≤ **A** ≤ 1,000" can be specified by `CONS(1 <= A && A <= 1000)`. "1 ≤ **A**, **B** ≤ 1,000" translates into two specifications: `CONS(1 <= A && A <= 1000)` and `CONS(1 <= B && B <= 1000)`. "1 ≤ **A** ≤ **B** ≤ 1,000" translates into `CONS(1 <= A && A <= B && B <= 1000)`.
+The constraint definition can be pulled directly from the constraints section in the actual problem description. For example:
+
+- "1 ≤ **A** ≤ 1,000" can be specified by `CONS(1 <= A && A <= 1000)`.
+- "1 ≤ **A**, **B** ≤ 1,000" translates into two specifications: `CONS(1 <= A && A <= 1000)` and `CONS(1 <= B && B <= 1000)`.
+- "1 ≤ **A** ≤ **B** ≤ 1,000" translates into `CONS(1 <= A && A <= B && B <= 1000)`.
 
 How about more complex predicates, such as "1 ≤ **A**[i] ≤ 1,000"? You can write a private method for this purpose. For example, it can be translated into `CONS(eachElementBetween(A, 1, 1000))` and a private method as follows:
 
@@ -41,6 +45,9 @@ bool eachElementBetween(const vector<int>& X, int lo, int hi) {
 
 This also applies to even more complex predicates, such as "It is guaranteed that the given graph is a tree". This can be translated to `CONS(graphIsTree())` and define the appropriate private boolean method.
 
-## Notes
+## Using built-in validators
+
+To simplify constraint specifications, TCFrame provides built-in [validators](../api/validators). For example:
 
-It is tedious to write `eachElementBetween()` predicate over and over again as it is very common in problems. We are working on providing such helper methods as core part of TCFrame in the next versions.
+- `CONS(1 <= A && A <= 1000)` can be rewritten as `CONS(valueOf(A).isBetween(1, 1000))`
+- `CONS(eachElementBetween(A, 1, 1000))` and the `eachElementBetween()` function can be rewritten as `CONS(eachElementOf(A).isBetween(1, 1000))`.

web/docs/topic-guides/11-grading.md

@@ -64,7 +64,7 @@ This will override what is set in `GradingConfig()`.
 
 ## Helper programs
 
-If [helper programs](../api/helper) are present, they must be compiled prior to the local grading.
+If [helper programs](../api/helpers) are present, they must be compiled prior to the local grading.
 
 ### Scorer
 

web/src/components/HomepageFeatures/index.js

@@ -16,8 +16,8 @@ void OutputFormat() {
 
 const constraints =
 `void Constraints() {
-    CONS(1 <= N && N <= 1000);
-    CONS(eachElementBetween(A, 1, 1000000));
+    CONS(valueOf(N).isBetween(1, 1000);
+    CONS(eachElementOf(A).isBetween(1, 10));
 }`
 
 const testCases =