Support multiple output formats (#141)

Resolve #123

docs/api-ref/api-ref.rst

@@ -69,13 +69,18 @@ Defines the input format. It is mandatory.
 
     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.
+Executed right before the produced output is validated against the output format(s). See :ref:`io-formats_before-output-format` for more details.
 
 .. sourcecode:: cpp
 
     virtual void OutputFormat() {}
 
-Defines the output format. It is optional; if not implemented, then the output will not be validated.
+    virtual void OutputFormat1() {}
+    virtual void OutputFormat2() {}
+    // ...
+    virtual void OutputFormat5() {}
+
+Defines the possible output format(s). If there is only one output format, only ``OutputFormat()`` can be specified, otherwise multiple ``OutputFormatX()`` should be specified.
 
 **Defining format**
 

docs/topic-guides/io-formats.rst

@@ -129,6 +129,41 @@ You can declare a helper variable, e.g. ``update_count``, and have ``LINES(answe
         LINES(answers) % SIZE(update_count);
     }
 
+----
+
+.. _io-formats_multiple-output-formats:
+
+Multiple output formats
+-----------------------
+
+Sometimes, there are more than one possible output formats. For example: "If there is no valid solution, output a single line containing -1. Otherwise, the first line of the output should contain **K**, followed by a line containing **K** space-separated integers representing the answer."
+
+This can be accomplished using ``OutputFormatX()``, where ``X`` is the output format number. A test case output is valid if it conforms to at least one of the output formats.
+
+.. note::
+
+    As of this version, you can define up to 5 output formats: **OutputFormat1()** .. **OutputFormat5()**.
+
+The above example could be implemented as follows.
+
+.. sourcecode:: cpp
+
+    int impossible;
+
+    int K;
+    vector<int> answers;
+
+    void OutputFormat1() {
+        LINE(impossible);
+    }
+
+    void OutputFormat2() {
+        LINE(K);
+        LINE(answers % SIZE(K));
+    }
+
+----
+
 Notes
 -----
 
@@ -139,13 +174,5 @@ Constants in I/O segments
 
     As a workaround, just create an input variable and initialize it to ``BEGIN``.
 
-Complex conditional I/O format that can't be handled by jagged vectors
-    There is **NO** known general workaround yet. We're still working on designing how to handle complex format.
-
-    However, there are workarounds for simple cases, for example:
-
-    "Output the required sum, or the string ``IMPOSSIBLE`` if there is no solution."
-
-    In this case, you can just use a string as the output variable. The downside is that it is not type-safe; for example, the generation won't fail if the reference solution mistakenly output an invalid string such as ``123abc``.
-
-However, a last resort for a workaround does exist for output format. If you have complex output format, you can just omit the method ``OutputFormat()`` altogether and your solution's output won't be checked at all for validity.
+Complex conditional I/O format that can't be handled by jagged vectors/raw line(s)
+    As a workaround, if you have a very complex output format, you can just omit the methods ``OutputFormat()``/``OutputFormatX()`` altogether and your solution's output won't be checked at all for validity.

include/tcframe/io_manipulator/IOManipulator.hpp

@@ -1,5 +1,8 @@
 #pragma once
 
+#include <istream>
+#include <ostream>
+#include <string>
 #include <vector>
 
 #include "GridIOSegmentManipulator.hpp"
@@ -12,6 +15,7 @@
 
 using std::istream;
 using std::ostream;
+using std::string;
 using std::vector;
 
 namespace tcframe {
@@ -35,9 +39,32 @@ class IOManipulator {
     }
 
     virtual void parseOutput(istream* in) {
-        if (!ioFormat_.outputFormat().empty()) {
+        if (!ioFormat_.outputFormats().empty()) {
             ioFormat_.beforeOutputFormat()();
-            parse(ioFormat_.outputFormat(), in);
+
+            long long initialPos = in->tellg();
+            bool successful = false;
+            string errorMessage;
+            for (const IOSegments& outputFormat : ioFormat_.outputFormats()) {
+                try {
+                    parse(outputFormat, in);
+                    successful = true;
+                    break;
+                } catch (runtime_error& e) {
+                    in->clear();
+                    in->seekg(initialPos);
+                    if (errorMessage.empty()) {
+                        errorMessage = e.what();
+                    }
+                }
+            }
+
+            if (!successful) {
+                if (ioFormat_.outputFormats().size() == 1) {
+                    throw runtime_error(errorMessage);
+                }
+                throw runtime_error("Test case output does not conform to any of the output formats");
+            }
         }
     }
 

include/tcframe/spec/core/BaseProblemSpec.hpp

@@ -20,6 +20,13 @@ class BaseProblemSpec
           protected MultipleTestCasesConfigBuilder,
           protected ConstraintSuiteBuilder {
 private:
+    vector<void(BaseProblemSpec::*)()> outputFormats_ = {
+            &BaseProblemSpec::OutputFormat1,
+            &BaseProblemSpec::OutputFormat2,
+            &BaseProblemSpec::OutputFormat3,
+            &BaseProblemSpec::OutputFormat4,
+            &BaseProblemSpec::OutputFormat5};
+
     vector<void(BaseProblemSpec::*)()> subtasks_ = {
             &BaseProblemSpec::Subtask1,
             &BaseProblemSpec::Subtask2,
@@ -56,8 +63,25 @@ class BaseProblemSpec
         IOFormatBuilder::setBeforeOutputFormat([this] {
             BeforeOutputFormat();
         });
-        IOFormatBuilder::prepareForOutputFormat();
-        OutputFormat();
+        try {
+            IOFormatBuilder::newOutputFormat();
+            OutputFormat();
+            for (auto outputFormat : outputFormats_) {
+                try {
+                    (this->*outputFormat)();
+                    throw runtime_error("If OutputFormat() is specified, no other OutputFormatX() can be specified");
+                } catch (NotImplementedException&) {}
+            }
+        } catch (NotImplementedException&) {
+            for (auto outputFormat : outputFormats_) {
+                try {
+                    (this->*outputFormat)();
+                    IOFormatBuilder::newOutputFormat();
+                } catch (NotImplementedException&) {
+                    break;
+                }
+            }
+        }
         return IOFormatBuilder::build();
     }
 
@@ -95,7 +119,12 @@ class BaseProblemSpec
 protected:
     virtual void InputFormat() = 0;
     virtual void BeforeOutputFormat() {}
-    virtual void OutputFormat() {}
+    virtual void OutputFormat() {throw NotImplementedException();}
+    virtual void OutputFormat1() {throw NotImplementedException();}
+    virtual void OutputFormat2() {throw NotImplementedException();}
+    virtual void OutputFormat3() {throw NotImplementedException();}
+    virtual void OutputFormat4() {throw NotImplementedException();}
+    virtual void OutputFormat5() {throw NotImplementedException();}
     virtual void StyleConfig() {}
     virtual void GradingConfig() {}
     virtual void MultipleTestCasesConfig() {}

include/tcframe/spec/io/IOFormat.hpp

@@ -25,7 +25,7 @@ struct IOFormat {
 private:
     IOSegments inputFormat_;
     function<void()> beforeOutputFormat_;
-    IOSegments outputFormat_;
+    vector<IOSegments> outputFormats_;
 
 public:
     const IOSegments& inputFormat() const {
@@ -36,12 +36,12 @@ struct IOFormat {
         return beforeOutputFormat_;
     }
 
-    const IOSegments& outputFormat() const {
-        return outputFormat_;
+    const vector<IOSegments>& outputFormats() const {
+        return outputFormats_;
     }
 
     bool operator==(const IOFormat& o) const {
-        return equals(inputFormat_, o.inputFormat_) && equals(outputFormat_, o.outputFormat_);
+        return equals(inputFormat_, o.inputFormat_) && equals(outputFormats_, o.outputFormats_);
     }
 
 private:
@@ -56,6 +56,18 @@ struct IOFormat {
         }
         return true;
     }
+
+    bool equals(const vector<IOSegments>& a, const vector<IOSegments>& b) const {
+        if (a.size() != b.size()) {
+            return false;
+        }
+        for (int i = 0; i < a.size(); i++) {
+            if (!equals(a[i], b[i])) {
+                return false;
+            }
+        }
+        return true;
+    }
 };
 
 class IOFormatBuilder {
@@ -77,9 +89,10 @@ class IOFormatBuilder {
         subject_.beforeOutputFormat_ = beforeOutputFormat;
     }
 
-    void prepareForOutputFormat() {
+    void newOutputFormat() {
         addLastSegment();
-        currentFormat_ = &subject_.outputFormat_;
+        subject_.outputFormats_.push_back(IOSegments());
+        currentFormat_ = &subject_.outputFormats_.back();
     }
 
     LineIOSegmentBuilder& newLineIOSegment() {
@@ -119,6 +132,9 @@ class IOFormatBuilder {
 
     IOFormat build() {
         addLastSegment();
+        if (!subject_.outputFormats_.empty() && subject_.outputFormats_.back().empty()) {
+            subject_.outputFormats_.pop_back();
+        }
         return move(subject_);
     }
 

test/ete/resources/normal-complex-formats/solution.cpp

@@ -1,9 +1,17 @@
 #include <cstdio>
 
-int A, B;
+int N;
+char buf[100];
 
 int main() {
-    printf("yes\n");
-    printf("lorem ipsum\n");
-    printf(" dolor sit amet! \n");
+    gets(buf);
+
+    scanf("%d", &N);
+    if (N == 1) {
+        printf("no it's impossible\n");
+    } else {
+        printf("yes\n");
+        printf("lorem ipsum\n");
+        printf(" dolor sit amet! \n");
+    }
 }

test/ete/resources/normal-complex-formats/spec.cpp

@@ -12,6 +12,7 @@ class ProblemSpec : public BaseProblemSpec {
     vector<int> X, Y;
     vector<vector<int>> M;
 
+    vector<string> res_impossible;
     string res;
     vector<string> answers;
 
@@ -23,7 +24,11 @@ class ProblemSpec : public BaseProblemSpec {
         GRID(M) % SIZE(2, 3);
     }
 
-    void OutputFormat() {
+    void OutputFormat1() {
+        LINE(res_impossible % SIZE(3));
+    }
+
+    void OutputFormat2() {
         LINE(res);
         RAW_LINES(answers);
     }
@@ -57,7 +62,21 @@ class TestSpec : public BaseTestSpec<ProblemSpec> {
         });
     }
 
+    void SampleTestCase2() {
+        Input({
+            "[BEGIN INPUT]",
+            "1",
+            "3 5",
+            "7 7 7",
+            "8 8 8"
+        });
+        Output({
+            "no it's impossible"
+        });
+    }
+
     void TestCases() {
+        CASE(S = "[BEGIN INPUT]", N = 1, A = {10, 20}, X = {}, Y = {}, M = { {1, 2, 3}, {4, 5, 6} });
         CASE(S = "[BEGIN INPUT]", N = 3, A = {10, 20}, X = {0, 0}, Y = {1, 1}, M = { {1, 2, 3}, {4, 5, 6} });
     }
 };

test/ete/tcframe/GenerationEteTests.cpp

@@ -42,8 +42,12 @@ TEST_F(GenerationEteTests, Normal_ComplexFormats) {
     EXPECT_THAT(ls("test-ete/normal-complex-formats/tc"), UnorderedElementsAre(
             "normal-complex-formats_sample_1.in",
             "normal-complex-formats_sample_1.out",
+            "normal-complex-formats_sample_2.in",
+            "normal-complex-formats_sample_2.out",
             "normal-complex-formats_1.in",
-            "normal-complex-formats_1.out"
+            "normal-complex-formats_1.out",
+            "normal-complex-formats_2.in",
+            "normal-complex-formats_2.out"
     ));
 }