Implement BeforeOutputFormat() (#121)

Resolves #38

docs/api-ref/api-ref.rst

@@ -65,6 +65,12 @@ Input/output formats
 
 Defines the input format. It is mandatory.
 
+.. sourcecode:: cpp
+
+    virtual void BeforeOutputFormat() {}
+
+Executed right before the produced output is validated against the output format. See :ref:`io-formats_before-output-format` for more details.
+
 .. sourcecode:: cpp
 
     virtual void OutputFormat() {}

docs/topic-guides/io-formats.rst

@@ -107,6 +107,28 @@ For more details, consult the :ref:`API reference for I/O formats <api-ref_io-fo
 
 ----
 
+.. _io-formats_before-output-format:
+
+BeforeOutputFormat()
+--------------------
+
+The special ``BeforeOutputFormat()`` method, if specified, will be executed right before the produced output is validated against the output format. It is useful when the output format segments depend on the input variables. For example, suppose that the input is a list of commands, each of which is either a query or an update. The output should contain as many lines as the number of update commands present in the input.
+
+You can declare a helper variable, e.g. ``update_count``, and have ``LINES(answers) % SIZE(update_count)`` as the output format. Then, compute the value of ``update_count`` in the ``BeforeOutputFormat()`` method. For example:
+
+.. sourcecode:: cpp
+
+    int update_count;
+    vector<int> answers;
+
+    void BeforeOutputFormat() {
+        // count the number of update queries and assign it to update_count
+    }
+
+    void OutputFormat() {
+        LINES(answers) % SIZE(update_count);
+    }
+
 Notes
 -----
 

include/tcframe/io_manipulator/IOManipulator.hpp

@@ -38,6 +38,7 @@ class IOManipulator {
 
     virtual void parseOutput(istream* in) {
         if (!ioFormat_.outputFormat().empty()) {
+            ioFormat_.beforeOutputFormat()();
             parse(ioFormat_.outputFormat(), in);
         }
     }

include/tcframe/spec/core/BaseProblemSpec.hpp

@@ -53,6 +53,9 @@ class BaseProblemSpec
     IOFormat buildIOFormat() {
         IOFormatBuilder::prepareForInputFormat();
         InputFormat();
+        IOFormatBuilder::setBeforeOutputFormat([this] {
+            BeforeOutputFormat();
+        });
         IOFormatBuilder::prepareForOutputFormat();
         OutputFormat();
         return IOFormatBuilder::build();
@@ -91,6 +94,7 @@ class BaseProblemSpec
 
 protected:
     virtual void InputFormat() = 0;
+    virtual void BeforeOutputFormat() {}
     virtual void OutputFormat() {}
     virtual void StyleConfig() {}
     virtual void GradingConfig() {}

include/tcframe/spec/io/IOFormat.hpp

@@ -1,5 +1,6 @@
 #pragma once
 
+#include <functional>
 #include <stdexcept>
 #include <utility>
 #include <vector>
@@ -11,6 +12,7 @@
 #include "RawLineIOSegment.hpp"
 #include "RawLinesIOSegment.hpp"
 
+using std::function;
 using std::move;
 using std::runtime_error;
 using std::vector;
@@ -22,13 +24,18 @@ struct IOFormat {
 
 private:
     vector<IOSegment*> inputFormat_;
+    function<void()> beforeOutputFormat_;
     vector<IOSegment*> outputFormat_;
 
 public:
     const vector<IOSegment*>& inputFormat() const {
         return inputFormat_;
     }
 
+    const function<void()>& beforeOutputFormat() const {
+        return beforeOutputFormat_;
+    }
+
     const vector<IOSegment*>& outputFormat() const {
         return outputFormat_;
     }
@@ -68,6 +75,10 @@ class IOFormatBuilder {
         currentFormat_ = &subject_.inputFormat_;
     }
 
+    void setBeforeOutputFormat(function<void()> beforeOutputFormat) {
+        subject_.beforeOutputFormat_ = beforeOutputFormat;
+    }
+
     void prepareForOutputFormat() {
         addLastSegment();
         currentFormat_ = &subject_.outputFormat_;

test/ete/resources/normal-lifecycle/solution.cpp

@@ -0,0 +1,7 @@
+#include <cstdio>
+
+int main() {
+    printf("even\n");
+    printf("odd\n");
+    printf("even\n");
+}

test/ete/resources/normal-lifecycle/spec.cpp

@@ -0,0 +1,64 @@
+#include <bits/stdc++.h>
+#include <tcframe/spec.hpp>
+
+using namespace std;
+using namespace tcframe;
+
+class ProblemSpec : public BaseProblemSpec {
+protected:
+    int N;
+    vector<int> A;
+
+    int positive_count;
+    vector<string> answers;
+
+    void InputFormat() {
+        LINE(N);
+        LINE(A % SIZE(N));
+    }
+
+    void BeforeOutputFormat() {
+        positive_count = count_if(A.begin(), A.end(), [](int a) {return a > 0;});
+    }
+
+    void OutputFormat() {
+        LINES(answers) % SIZE(positive_count);
+    }
+
+    void GradingConfig() {
+        TimeLimit(2);
+        MemoryLimit(64);
+    }
+
+    void Constraints() {
+        CONS(1 <= N && N <= 10);
+    }
+};
+
+class TestSpec : public BaseTestSpec<ProblemSpec> {
+protected:
+    void BeforeTestCase() {
+        A.clear();
+    }
+
+    void AfterTestCase() {
+        N++;
+        A.push_back(-100);
+    }
+
+    void SampleTestCase1() {
+        Input({
+            "5",
+            "4 -1 3 2 -5",
+        });
+        Output({
+            "even",
+            "odd",
+            "even"
+        });
+    }
+
+    void TestCases() {
+        CASE(N = 6, A = {-1, 2, 3, -4, -5, 6});
+    }
+};

test/ete/tcframe/GenerationEteTests.cpp

@@ -62,6 +62,35 @@ TEST_F(GenerationEteTests, Normal_CustomScorer) {
     ));
 }
 
+TEST_F(GenerationEteTests, Normal_Lifecycle) {
+    ASSERT_THAT(execStatus("cd test-ete/normal-lifecycle && ../scripts/generate.sh"), Eq(0));
+
+    EXPECT_THAT(ls("test-ete/normal-lifecycle/tc"), UnorderedElementsAre(
+            "normal-lifecycle_sample_1.in",
+            "normal-lifecycle_sample_1.out",
+            "normal-lifecycle_1.in",
+            "normal-lifecycle_1.out"
+    ));
+
+    EXPECT_THAT(readFile("test-ete/normal-lifecycle/tc/normal-lifecycle_sample_1.in"), Eq(
+            "5\n"
+            "4 -1 3 2 -5\n"));
+
+    EXPECT_THAT(readFile("test-ete/normal-lifecycle/tc/normal-lifecycle_sample_1.out"), Eq(
+            "even\n"
+            "odd\n"
+            "even\n"));
+
+    EXPECT_THAT(readFile("test-ete/normal-lifecycle/tc/normal-lifecycle_1.in"), Eq(
+            "7\n"
+            "-1 2 3 -4 -5 6 -100\n"));
+
+    EXPECT_THAT(readFile("test-ete/normal-lifecycle/tc/normal-lifecycle_1.out"), Eq(
+            "even\n"
+            "odd\n"
+            "even\n"));
+}
+
 TEST_F(GenerationEteTests, Subtasks) {
     ASSERT_THAT(execStatus("cd test-ete/subtasks && ../scripts/generate.sh"), Eq(0));
 

test/unit/tcframe/io_manipulator/IOManipulatorTests.cpp

@@ -16,15 +16,17 @@ namespace tcframe {
 class IOManipulatorTests : public Test {
 protected:
     int A;
+    int N;
     string S;
     vector<int> V;
     vector<string> W;
     vector<vector<int>> M;
 
+    IOManipulator* manipulatorEmpty;
+    IOManipulator* manipulatorWithOutputFormat;
     IOManipulator* manipulatorWithScalarLast;
     IOManipulator* manipulatorWithVectorLast;
     IOManipulator* manipulatorWithMatrixLast;
-    IOManipulator* manipulatorEmpty;
 
     void SetUp() {
         {
@@ -34,6 +36,17 @@ class IOManipulatorTests : public Test {
 
             manipulatorEmpty = new IOManipulator(ioFormat);
         }
+        {
+            IOFormatBuilder ioFormatBuilder;
+            ioFormatBuilder.prepareForOutputFormat();
+            ioFormatBuilder.setBeforeOutputFormat([=] {N = 3;});
+            ioFormatBuilder.newLinesIOSegment()
+                    .addVectorVariable(Vector::create(V, "V"))
+                    .setSize([=] {return N;});
+            IOFormat ioFormat = ioFormatBuilder.build();
+
+            manipulatorWithOutputFormat = new IOManipulator(ioFormat);
+        }
         {
             IOFormatBuilder ioFormatBuilder;
             ioFormatBuilder.prepareForInputFormat();
@@ -128,6 +141,13 @@ TEST_F(IOManipulatorTests, Parsing_Failed_MissingEof_WithMatrixLast) {
     }
 }
 
+TEST_F(IOManipulatorTests, Parsing_Output) {
+    istringstream in("1\n2\n3\n");
+    N = 0;
+    manipulatorWithOutputFormat->parseOutput(&in);
+    EXPECT_THAT(V, Eq((vector<int>{1, 2, 3})));
+}
+
 TEST_F(IOManipulatorTests, Printing_Successful) {
     A = 123;
     S = "hello, world!";