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/*
* MRustC - Rust Compiler
* - By John Hodge (Mutabah/thePowersGang)
*
* parse/lex.hpp
* - Lexer header
*/
#ifndef LEX_HPP_INCLUDED
#define LEX_HPP_INCLUDED
#include <debug.hpp>
#include <serialise.hpp>
#include "../coretypes.hpp"
#include <string>
#include <fstream>
#include "../include/span.hpp"
#include "token.hpp"
namespace AST {
class Module;
class MetaItems;
}
/// State the parser needs to pass down via a second channel.
struct ParseState
{
// Used for "for/if/while" to handle ambiguity
bool disallow_struct_literal = false;
// A debugging hook that disables expansion of macros
bool no_expand_macros = false;
::AST::Module* module = nullptr;
::AST::MetaItems* parent_attrs = nullptr;
::AST::Module& get_current_mod() {
assert(this->module);
return *this->module;
}
friend ::std::ostream& operator<<(::std::ostream& os, const ParseState& ps) {
os << "ParseState {";
if(ps.disallow_struct_literal) os << " disallow_struct_literal";
if(ps.no_expand_macros) os << " no_expand_macros";
os << " }";
return os;
}
};
class TokenStream
{
friend class TTLexer; // needs access to internals to know what was consumed
bool m_cache_valid;
Token m_cache;
::std::vector<Token> m_lookahead;
ParseState m_parse_state;
public:
TokenStream();
virtual ~TokenStream();
Token getToken();
void putback(Token tok);
eTokenType lookahead(unsigned int count);
virtual Position getPosition() const = 0;
ParseState& parse_state() { return m_parse_state; }
ProtoSpan start_span() const;
Span end_span(ProtoSpan ps) const;
protected:
virtual Token realGetToken() = 0;
private:
Token innerGetToken();
};
class SavedParseState
{
TokenStream& m_lex;
ParseState m_state;
public:
SavedParseState(TokenStream& lex, ParseState state):
m_lex(lex),
m_state(state)
{
}
~SavedParseState()
{
DEBUG("Restoring " << m_state);
m_lex.parse_state() = m_state;
}
};
#define SET_MODULE(lex, mod) SavedParseState _sps(lex, lex.parse_state()); lex.parse_state().module = &(mod)
#define SET_ATTRS(lex, attrs) SavedParseState _sps(lex, lex.parse_state()); lex.parse_state().parent_attrs = &(attrs)
#define SET_PARSE_FLAG(lex, flag) SavedParseState _sps(lex, lex.parse_state()); lex.parse_state().flag = true
#define CLEAR_PARSE_FLAG(lex, flag) SavedParseState _sps(lex, lex.parse_state()); lex.parse_state().flag = false
#define CHECK_PARSE_FLAG(lex, flag) (lex.parse_state().flag == true)
struct Codepoint {
uint32_t v;
Codepoint(): v(0) { }
Codepoint(uint32_t v): v(v) { }
bool isspace() const;
bool isdigit() const;
bool isxdigit() const;
bool operator==(char x) { return v == static_cast<uint32_t>(x); }
bool operator!=(char x) { return v != static_cast<uint32_t>(x); }
bool operator==(Codepoint x) { return v == x.v; }
bool operator!=(Codepoint x) { return v != x.v; }
};
extern ::std::string& operator+=(::std::string& s, const Codepoint& cp);
extern ::std::ostream& operator<<(::std::ostream& s, const Codepoint& cp);
typedef Codepoint uchar;
class Lexer:
public TokenStream
{
RcString m_path;
unsigned int m_line;
unsigned int m_line_ofs;
::std::ifstream m_istream;
bool m_last_char_valid;
Codepoint m_last_char;
Token m_next_token; // Used when lexing generated two tokens
public:
Lexer(const ::std::string& filename);
virtual Position getPosition() const override;
virtual Token realGetToken() override;
private:
Token getTokenInt();
signed int getSymbol();
Token getTokenInt_RawString(bool is_byte);
Token getTokenInt_Identifier(Codepoint ch, Codepoint ch2='\0');
double parseFloat(uint64_t whole);
uint32_t parseEscape(char enclosing);
void ungetc();
Codepoint getc_num();
Codepoint getc();
Codepoint getc_cp();
char getc_byte();
class EndOfFile {};
};
#endif // LEX_HPP_INCLUDED
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