Compiler_Parser_Utils.H

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/*
                          Aleph_w
 
  Data structures & Algorithms
  version 2.0.0b
  https://github.com/lrleon/Aleph-w
 
  This file is part of Aleph-w library
 
  Copyright (c) 2002-2026 Leandro Rabindranath Leon
 
  Permission is hereby granted, free of charge, to any person obtaining a copy
  of this software and associated documentation files (the "Software"), to deal
  in the Software without restriction, including without limitation the rights
  to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  copies of the Software, and to permit persons to whom the Software is
  furnished to do so, subject to the following conditions:
 
  The above copyright notice and this permission notice shall be included in all
  copies or substantial portions of the Software.
 
  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
  SOFTWARE.
*/
 
#ifndef COMPILER_PARSER_UTILS_H
#define COMPILER_PARSER_UTILS_H
 
#include <string>
#include <string_view>
 
#include <Compiler_Lexer.H>
 
namespace Aleph {
inline bool compiler_is_expression_start(const Compiler_Token_Kind kind) noexcept
{
  switch (kind)
    {
    case Compiler_Token_Kind::Identifier:
    case Compiler_Token_Kind::Integer_Literal:
    case Compiler_Token_Kind::String_Literal:
    case Compiler_Token_Kind::Char_Literal:
    case Compiler_Token_Kind::Kw_True:
    case Compiler_Token_Kind::Kw_False:
    case Compiler_Token_Kind::LParen:
    case Compiler_Token_Kind::Bang:
    case Compiler_Token_Kind::Minus:
    case Compiler_Token_Kind::Plus:
    case Compiler_Token_Kind::Tilde:
      return true;
    default:
      return false;
    }
}
 
inline bool compiler_is_statement_start(const Compiler_Token_Kind kind) noexcept
{
  switch (kind)
    {
    case Compiler_Token_Kind::LBrace:
    case Compiler_Token_Kind::Kw_Let:
    case Compiler_Token_Kind::Kw_Return:
    case Compiler_Token_Kind::Kw_If:
    case Compiler_Token_Kind::Kw_While:
    case Compiler_Token_Kind::Kw_Break:
    case Compiler_Token_Kind::Kw_Continue:
      return true;
    default:
      return compiler_is_expression_start(kind);
    }
}
 
inline bool compiler_is_top_level_declaration_start(const Compiler_Token_Kind kind) noexcept
{
  switch (kind)
    {
    case Compiler_Token_Kind::Kw_Import:
    case Compiler_Token_Kind::Kw_Fn:
    case Compiler_Token_Kind::Kw_Type:
    case Compiler_Token_Kind::Kw_Struct:
    case Compiler_Token_Kind::Kw_Enum:
      return true;
    default:
      return false;
    }
}
 
inline std::string compiler_unquote_string_token(const Compiler_Token &token)
{
  if (token.kind != Compiler_Token_Kind::String_Literal)
    return token.lexeme;
  if (token.lexeme.size() >= 2 and token.lexeme.front() == '"' and token.lexeme.back() == '"')
    return token.lexeme.substr(1, token.lexeme.size() - 2);
  return token.lexeme;
}
 
class Compiler_Parser_Stream
{
  Compiler_Lexer *lexer = nullptr;
  Diagnostic_Engine *diagnostics = nullptr;
 
  void emit_error(const Source_Span &span,
                  const std::string &message,
                  const std::string &code,
                  const std::string &note = "",
                  const std::string &help = "") const
  {
    if (diagnostics == nullptr)
      return;
 
    auto builder = diagnostics->error(span, message).code(code);
    if (not note.empty())
      builder.note(note);
    if (not help.empty())
      builder.help(help);
    builder.emit();
  }
 
public:
  Compiler_Parser_Stream(Compiler_Lexer &token_source, Diagnostic_Engine *dx = nullptr) noexcept
    : lexer(&token_source), diagnostics(dx)
  {}
 
  [[nodiscard]] Compiler_Token peek()
  {
    return lexer->peek();
  }
 
  [[nodiscard]] Compiler_Token next()
  {
    return lexer->next();
  }
 
  [[nodiscard]] bool check(const Compiler_Token_Kind kind)
  {
    return peek().kind == kind;
  }
 
  bool match(const Compiler_Token_Kind kind)
  {
    if (not check(kind))
      return false;
    (void) next();
    return true;
  }
 
  [[nodiscard]] Compiler_Token expect(const Compiler_Token_Kind kind,
                                      const std::string &message,
                                      const std::string &code,
                                      const std::string &note = "",
                                      const std::string &help = "")
  {
    const auto tok = peek();
    if (tok.kind == kind)
      return next();
 
    emit_error(tok.span, message, code, note, help);
    return {kind, "", tok.span};
  }
 
  [[nodiscard]] Compiler_Token expect_identifier(const std::string_view context,
                                                 const std::string &code = "PAR002")
  {
    const auto tok = peek();
    if (tok.kind == Compiler_Token_Kind::Identifier)
      return next();
 
    emit_error(tok.span, "expected identifier " + std::string(context), code);
    return {Compiler_Token_Kind::Identifier, "", tok.span};
  }
 
  template <typename Parse_Item>
  bool parse_separated_list(const Compiler_Token_Kind separator,
                            const Compiler_Token_Kind terminator,
                            Parse_Item &&parse_item,
                            const bool allow_trailing_separator = false)
  {
    if (check(terminator))
      return true;
 
    while (true)
      {
        if (not parse_item())
          return false;
 
        if (not match(separator))
          return true;
 
        if (allow_trailing_separator and check(terminator))
          return true;
      }
  }
 
  void synchronize_statement()
  {
    while (true)
      {
        const auto tok = peek();
        if (tok.is_eof() or tok.kind == Compiler_Token_Kind::RBrace
            or compiler_is_top_level_declaration_start(tok.kind))
          return;
 
        switch (tok.kind)
          {
          case Compiler_Token_Kind::LBrace:
          case Compiler_Token_Kind::Kw_Let:
          case Compiler_Token_Kind::Kw_Return:
          case Compiler_Token_Kind::Kw_If:
          case Compiler_Token_Kind::Kw_While:
          case Compiler_Token_Kind::Kw_Break:
          case Compiler_Token_Kind::Kw_Continue:
            return;
          default:
            break;
          }
 
        if (tok.kind == Compiler_Token_Kind::Semicolon)
          {
            (void) next();
            return;
          }
 
        (void) next();
      }
  }
};
}  // namespace Aleph
 
#endif