add antlr

lib/antlr4/include/atn/SemanticContext.h

@@ -0,0 +1,222 @@
+/* Copyright (c) 2012-2017 The ANTLR Project. All rights reserved.
+ * Use of this file is governed by the BSD 3-clause license that
+ * can be found in the LICENSE.txt file in the project root.
+ */
+
+#pragma once
+
+#include "Recognizer.h"
+#include "support/CPPUtils.h"
+
+namespace antlr4 {
+namespace atn {
+
+  /// A tree structure used to record the semantic context in which
+  ///  an ATN configuration is valid.  It's either a single predicate,
+  ///  a conjunction "p1 && p2", or a sum of products "p1||p2".
+  ///
+  ///  I have scoped the AND, OR, and Predicate subclasses of
+  ///  SemanticContext within the scope of this outer class.
+  class ANTLR4CPP_PUBLIC SemanticContext : public std::enable_shared_from_this<SemanticContext> {
+  public:
+    struct Hasher
+    {
+      size_t operator()(Ref<SemanticContext> const& k) const {
+        return k->hashCode();
+      }
+    };
+
+    struct Comparer {
+      bool operator()(Ref<SemanticContext> const& lhs, Ref<SemanticContext> const& rhs) const {
+        if (lhs == rhs)
+          return true;
+        return (lhs->hashCode() == rhs->hashCode()) && (*lhs == *rhs);
+      }
+    };
+
+
+    using Set = std::unordered_set<Ref<SemanticContext>, Hasher, Comparer>;
+
+    /**
+     * The default {@link SemanticContext}, which is semantically equivalent to
+     * a predicate of the form {@code {true}?}.
+     */
+    static const Ref<SemanticContext> NONE;
+
+    virtual ~SemanticContext();
+
+    virtual size_t hashCode() const = 0;
+    virtual std::string toString() const = 0;
+    virtual bool operator == (const SemanticContext &other) const = 0;
+    virtual bool operator != (const SemanticContext &other) const;
+
+    /// <summary>
+    /// For context independent predicates, we evaluate them without a local
+    /// context (i.e., null context). That way, we can evaluate them without
+    /// having to create proper rule-specific context during prediction (as
+    /// opposed to the parser, which creates them naturally). In a practical
+    /// sense, this avoids a cast exception from RuleContext to myruleContext.
+    /// <p/>
+    /// For context dependent predicates, we must pass in a local context so that
+    /// references such as $arg evaluate properly as _localctx.arg. We only
+    /// capture context dependent predicates in the context in which we begin
+    /// prediction, so we passed in the outer context here in case of context
+    /// dependent predicate evaluation.
+    /// </summary>
+    virtual bool eval(Recognizer *parser, RuleContext *parserCallStack) = 0;
+
+    /**
+     * Evaluate the precedence predicates for the context and reduce the result.
+     *
+     * @param parser The parser instance.
+     * @param parserCallStack
+     * @return The simplified semantic context after precedence predicates are
+     * evaluated, which will be one of the following values.
+     * <ul>
+     * <li>{@link #NONE}: if the predicate simplifies to {@code true} after
+     * precedence predicates are evaluated.</li>
+     * <li>{@code null}: if the predicate simplifies to {@code false} after
+     * precedence predicates are evaluated.</li>
+     * <li>{@code this}: if the semantic context is not changed as a result of
+     * precedence predicate evaluation.</li>
+     * <li>A non-{@code null} {@link SemanticContext}: the new simplified
+     * semantic context after precedence predicates are evaluated.</li>
+     * </ul>
+     */
+    virtual Ref<SemanticContext> evalPrecedence(Recognizer *parser, RuleContext *parserCallStack);
+
+    static Ref<SemanticContext> And(Ref<SemanticContext> const& a, Ref<SemanticContext> const& b);
+
+    /// See also: ParserATNSimulator::getPredsForAmbigAlts.
+    static Ref<SemanticContext> Or(Ref<SemanticContext> const& a, Ref<SemanticContext> const& b);
+
+    class Predicate;
+    class PrecedencePredicate;
+    class Operator;
+    class AND;
+    class OR;
+
+  private:
+    static std::vector<Ref<PrecedencePredicate>> filterPrecedencePredicates(const Set &collection);
+  };
+
+  class ANTLR4CPP_PUBLIC SemanticContext::Predicate : public SemanticContext {
+  public:
+    const size_t ruleIndex;
+    const size_t predIndex;
+    const bool isCtxDependent; // e.g., $i ref in pred
+
+  protected:
+    Predicate();
+
+  public:
+    Predicate(size_t ruleIndex, size_t predIndex, bool isCtxDependent);
+
+    virtual bool eval(Recognizer *parser, RuleContext *parserCallStack) override;
+    virtual size_t hashCode() const override;
+    virtual bool operator == (const SemanticContext &other) const override;
+    virtual std::string toString() const override;
+  };
+
+  class ANTLR4CPP_PUBLIC SemanticContext::PrecedencePredicate : public SemanticContext {
+  public:
+    const int precedence;
+
+  protected:
+    PrecedencePredicate();
+
+  public:
+    PrecedencePredicate(int precedence);
+
+    virtual bool eval(Recognizer *parser, RuleContext *parserCallStack) override;
+    virtual Ref<SemanticContext> evalPrecedence(Recognizer *parser, RuleContext *parserCallStack) override;
+    virtual int compareTo(PrecedencePredicate *o);
+    virtual size_t hashCode() const override;
+    virtual bool operator == (const SemanticContext &other) const override;
+    virtual std::string toString() const override;
+  };
+
+  /**
+   * This is the base class for semantic context "operators", which operate on
+   * a collection of semantic context "operands".
+   *
+   * @since 4.3
+   */
+  class ANTLR4CPP_PUBLIC SemanticContext::Operator : public SemanticContext {
+  public:
+    virtual ~Operator() override;
+
+    /**
+     * Gets the operands for the semantic context operator.
+     *
+     * @return a collection of {@link SemanticContext} operands for the
+     * operator.
+     *
+     * @since 4.3
+     */
+
+    virtual std::vector<Ref<SemanticContext>> getOperands() const = 0;
+  };
+
+  /**
+   * A semantic context which is true whenever none of the contained contexts
+   * is false.
+   */
+  class ANTLR4CPP_PUBLIC SemanticContext::AND : public SemanticContext::Operator {
+  public:
+    std::vector<Ref<SemanticContext>> opnds;
+
+    AND(Ref<SemanticContext> const& a, Ref<SemanticContext> const& b) ;
+
+    virtual std::vector<Ref<SemanticContext>> getOperands() const override;
+    virtual bool operator == (const SemanticContext &other) const override;
+    virtual size_t hashCode() const override;
+
+    /**
+     * The evaluation of predicates by this context is short-circuiting, but
+     * unordered.</p>
+     */
+    virtual bool eval(Recognizer *parser, RuleContext *parserCallStack) override;
+    virtual Ref<SemanticContext> evalPrecedence(Recognizer *parser, RuleContext *parserCallStack) override;
+    virtual std::string toString() const override;
+  };
+
+  /**
+   * A semantic context which is true whenever at least one of the contained
+   * contexts is true.
+   */
+  class ANTLR4CPP_PUBLIC SemanticContext::OR : public SemanticContext::Operator {
+  public:
+    std::vector<Ref<SemanticContext>> opnds;
+
+    OR(Ref<SemanticContext> const& a, Ref<SemanticContext> const& b);
+
+    virtual std::vector<Ref<SemanticContext>> getOperands() const override;
+    virtual bool operator == (const SemanticContext &other) const override;
+    virtual size_t hashCode() const override;
+
+    /**
+     * The evaluation of predicates by this context is short-circuiting, but
+     * unordered.
+     */
+    virtual bool eval(Recognizer *parser, RuleContext *parserCallStack) override;
+    virtual Ref<SemanticContext> evalPrecedence(Recognizer *parser, RuleContext *parserCallStack) override;
+    virtual std::string toString() const override;
+  };
+
+} // namespace atn
+} // namespace antlr4
+
+// Hash function for SemanticContext, used in the MurmurHash::update function
+
+namespace std {
+  using antlr4::atn::SemanticContext;
+
+  template <> struct hash<SemanticContext>
+  {
+    size_t operator () (SemanticContext &x) const
+    {
+      return x.hashCode();
+    }
+  };
+}