fixed parsing derived predicates

drexlerd · May 26, 2024 · b10e9fc · b10e9fc
1 parent 0191959
commit b10e9fc
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Showing 3 changed files with 12 additions and 1 deletion.
diff --git a/include/loki/details/pddl/context.hpp b/include/loki/details/pddl/context.hpp
@@ -36,6 +36,8 @@ struct Context
     ScopeStack& scopes;
     // For strict error checking
     bool strict;
+    // Toggle error checks during parsing
+    bool allow_free_variables;
     // For checking that certain PDDL objects were referenced at least once
     ReferencedPDDLObjects references;
     // For convenience, to avoid an additional parameter during semantic parsing
@@ -47,6 +49,7 @@ struct Context
         positions(positions_),
         scopes(scopes_),
         strict(strict_),
+        allow_free_variables(false),
         references(ReferencedPDDLObjects()),
         requirements(nullptr)
     {

diff --git a/src/pddl/parser/common.cpp b/src/pddl/parser/common.cpp
@@ -79,7 +79,10 @@ Term TermReferenceTermVisitor::operator()(const ast::Name& node) const
 Term TermReferenceTermVisitor::operator()(const ast::Variable& node) const
 {
     const auto variable = parse(node, context);
-    test_undefined_variable(variable, node, context);
+    if (!context.allow_free_variables)
+    {
+        test_undefined_variable(variable, node, context);
+    }
     const auto term = context.factories.get_or_create_term_variable(variable);
     context.positions.push_back(term, node);
     return term;

diff --git a/src/pddl/parser/structure.cpp b/src/pddl/parser/structure.cpp
@@ -64,9 +64,14 @@ Axiom parse(const ast::Axiom& node, Context& context)
 {
     test_undefined_requirement(RequirementEnum::DERIVED_PREDICATES, node, context);
     context.references.untrack(RequirementEnum::DERIVED_PREDICATES);
+
+    // Allow free variables in axiom head and body
+    context.allow_free_variables = true;
     const auto literal = parse(node.literal, context);
     test_expected_derived_predicate(literal->get_atom()->get_predicate(), node, context);
     const auto condition = parse(node.goal_descriptor, context);
+    context.allow_free_variables = false;
+
     // Free variables and literal variables become explicit parameters
     auto variables = collect_free_variables(*condition);
     for (const auto& term : literal->get_atom()->get_terms())