Added upper bounds for sequences (#149)

* Added top-level option shape to well-formedness specifications * Replaced Option class by extended Sequence class * Bounds checking for sequences --------- Co-authored-by: Sylvan Clebsch <[email protected]>
microsoft · Dec 16, 2024 · 5858239 · 5858239
1 parent 7825421
commit 5858239
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Showing 2 changed files with 62 additions and 13 deletions.
diff --git a/include/trieste/wf.h b/include/trieste/wf.h
@@ -246,10 +246,13 @@ namespace trieste
     struct Sequence
     {
       Choice choice;
-      size_t minlen;
+      size_t min_len;
+      size_t max_len;
+      bool has_minlen = false;
+      bool has_maxlen = false;
 
-      SNMALLOC_SLOW_PATH Sequence(Choice choice_, size_t minlen_) :
-        choice{choice_}, minlen{minlen_} {}
+      SNMALLOC_SLOW_PATH Sequence(Choice choice_, size_t minlen_, size_t maxlen_) :
+        choice{choice_}, min_len{minlen_}, max_len(maxlen_) {}
       SNMALLOC_SLOW_PATH Sequence() = default;
       SNMALLOC_SLOW_PATH Sequence(const Sequence&) = default;
       SNMALLOC_SLOW_PATH Sequence(Sequence&&) = default;
@@ -262,9 +265,30 @@ namespace trieste
         return std::numeric_limits<size_t>::max();
       }
 
-      Sequence& operator[](size_t new_minlen)
+      Sequence& operator[](size_t new_len)
       {
-        minlen = new_minlen;
+        if (has_minlen && has_maxlen)
+          throw std::runtime_error(
+            "Too many bounds when building sequence: ["
+            + std::to_string(min_len) + "]["
+            + std::to_string(max_len) + "]["
+            + std::to_string(new_len) + "]");
+
+        if (has_minlen && !has_maxlen && new_len < min_len)
+          throw std::runtime_error(
+            "Upper bound is below lower bound when building sequence: ["
+            + std::to_string(min_len) + "][" + std::to_string(new_len) + "]");
+
+        if (!has_minlen)
+        {
+          min_len = new_len;
+          has_minlen = true;
+        }
+        else
+        {
+          max_len = new_len;
+          has_maxlen = true;
+        }
         return *this;
       }
 
@@ -285,10 +309,19 @@ namespace trieste
           ok = choice.check(child) && ok;
         }
 
-        if (!has_err && (node->size() < minlen))
+        if (!has_err && (node->size() < min_len))
         {
           logging::Error() << node->location().origin_linecol()
-                           << ": expected at least " << minlen
+                           << ": expected at least " << min_len
+                           << " children, found " << node->size() << std::endl
+                           << node->location().str() << node << std::endl;
+          ok = false;
+        }
+
+        if (!has_err && (node->size() > max_len))
+        {
+          logging::Error() << node->location().origin_linecol()
+                           << ": expected at most " << max_len
                            << " children, found " << node->size() << std::endl
                            << node->location().str() << node << std::endl;
           ok = false;
@@ -305,10 +338,11 @@ namespace trieste
 
       void gen(Gen& g, size_t depth, Node node) const
       {
-        for (size_t i = 0; i < minlen; ++i)
+        size_t i;
+        for (i = 0; i < min_len; ++i)
           choice.gen(g, depth, node);
 
-        while (g.next() % 2)
+        while (i++ < max_len && g.next() % 2)
           choice.gen(g, depth, node);
       }
     };
@@ -830,17 +864,32 @@ namespace trieste
 
       inline Sequence operator++(const Token& type, int)
       {
-        return Sequence{Choice{std::vector<Token>{type}}, 0};
+        return Sequence{Choice{std::vector<Token>{type}}, 0, std::numeric_limits<size_t>::max()};
       }
 
       inline Sequence operator++(const Choice& choice, int)
       {
-        return Sequence{choice, 0};
+        return Sequence{choice, 0, std::numeric_limits<size_t>::max()};
       }
 
       inline Sequence operator++(Choice&& choice, int)
       {
-        return Sequence{choice, 0};
+        return Sequence{choice, 0, std::numeric_limits<size_t>::max()};
+      }
+
+      inline Sequence operator~(const Token& type)
+      {
+        return Sequence{Choice{std::vector<Token>{type}}, 0, 1};
+      }
+
+      inline Sequence operator~(const Choice& choice)
+      {
+        return Sequence{choice, 0, 1};
+      }
+
+      inline Sequence operator~(Choice&& choice)
+      {
+        return Sequence{choice, 0, 1};
       }
 
       inline Field operator>>=(const Token& name, const Token& type)

diff --git a/parsers/json/internal.h b/parsers/json/internal.h
@@ -19,7 +19,7 @@ namespace trieste
     // clang-format off
     inline const auto wf_parse =
       (Top <<= File)
-      | (File <<= Group++)
+      | (File <<= ~Group)
       | (Value <<= Group)
       | (Array <<= Group)
       | (Object <<= Group)