src/tint/ast/override.h

// Copyright 2022 The Tint Authors.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

#ifndef SRC_TINT_AST_OVERRIDE_H_
#define SRC_TINT_AST_OVERRIDE_H_

#include <string>

#include "src/tint/ast/variable.h"

namespace tint::ast {

/// An "override" declaration - a name for a pipeline-overridable constant.
/// Examples:
///
/// ```
///   override radius : i32 = 2;       // Can be overridden by name.
///   @id(5) override width : i32 = 2; // Can be overridden by ID.
///   override scale : f32;            // No default - must be overridden.
/// ```
/// @see https://www.w3.org/TR/WGSL/#override-decls
class Override final : public Castable<Override, Variable> {
  public:
    /// Create an 'override' pipeline-overridable constant.
    /// @param pid the identifier of the program that owns this node
    /// @param nid the unique node identifier
    /// @param source the variable source
    /// @param sym the variable symbol
    /// @param type the declared variable type
    /// @param constructor the constructor expression
    /// @param attributes the variable attributes
    Override(ProgramID pid,
             NodeID nid,
             const Source& source,
             const Symbol& sym,
             const ast::Type* type,
             const Expression* constructor,
             AttributeList attributes);

    /// Move constructor
    Override(Override&&);

    /// Destructor
    ~Override() override;

    /// @returns "override"
    const char* Kind() const override;

    /// Clones this node and all transitive child nodes using the `CloneContext`
    /// `ctx`.
    /// @param ctx the clone context
    /// @return the newly cloned node
    const Override* Clone(CloneContext* ctx) const override;

    /// @param symbols the symbol table to retrieve the name from
    /// @returns the identifier string for the override. If the override has
    /// an ID attribute, the string is the id-stringified. Otherwise, the ID
    /// is the symbol.
    std::string Identifier(const SymbolTable& symbols) const;
};

}  // namespace tint::ast

#endif  // SRC_TINT_AST_OVERRIDE_H_