typedef struct OS_Memory OS_Memory;
struct OS_Memory{
void *data;
SizeU commit;
SizeU reserve;
};

typedef struct Arena Arena;
struct Arena{
union{
OS_Memory memory;
struct {
void *data;
SizeU commit;
SizeU reserve;
};
}
U64 len;
U64 alignment;
};

typedef struct String String;
struct String{
U8 *str;
S64 len;
};

typedef String Intern_String;
typedef enum Token_Kind{
  TK_End,
  TK_Mul,
  TK_Div,
  TK_Add,
  TK_Sub,
  TK_Mod,
  TK_BitAnd,
  TK_BitOr,
  TK_BitXor,
  TK_Neg,
  TK_Not,
  TK_OpenParen,
  TK_CloseParen,
  TK_OpenBrace,
  TK_CloseBrace,
  TK_OpenBracket,
  TK_CloseBracket,
  TK_Comma,
  TK_Pound,
  TK_Question,
  TK_ThreeDots,
  TK_Semicolon,
  TK_Dot,
  TK_LesserThen,
  TK_GreaterThen,
  TK_Colon,
  TK_Assign,
  TK_DivAssign,
  TK_MulAssign,
  TK_ModAssign,
  TK_SubAssign,
  TK_AddAssign,
  TK_AndAssign,
  TK_OrAssign,
  TK_XorAssign,
  TK_LeftShiftAssign,
  TK_RightShiftAssign,
  TK_DoubleColon,
  TK_At,
  TK_Decrement,
  TK_Increment,
  TK_PostDecrement,
  TK_PostIncrement,
  TK_LesserThenOrEqual,
  TK_GreaterThenOrEqual,
  TK_Equals,
  TK_And,
  TK_Or,
  TK_NotEquals,
  TK_LeftShift,
  TK_RightShift,
  TK_Arrow,
  TK_ExprSizeof,
  TK_DocComment,
  TK_Comment,
  TK_Identifier,
  TK_StringLit,
  TK_U8Lit,
  TK_Character,
  TK_Error,
  TK_Float,
  TK_Int,
  TK_Keyword,
}Token_Kind;

typedef struct Token Token;
struct Token{
Token_Kind kind;
union{
String string;
struct {
U8 *str;
S64 len;
};
}
union {
S64 int_val;
String error_val;
Intern_String intern_val;
};
String file;
S64 line;
U8 *line_begin;
};

typedef struct Tokens Tokens;
struct Tokens{
Token *tokens;
S64 len;
S64 cap;
S64 iter;
};

typedef struct Lex_Stream Lex_Stream;
struct Lex_Stream{
U8 *stream;
U8 *line_begin;
String filename;
S64 line;
};

typedef enum Expr_Kind{
  EK_None,
  EK_Atom,
  EK_Unary,
  EK_Binary,
  EK_Ternary,
  EK_Cast,
  EK_List,
  EK_Call,
  EK_Index,
}Expr_Kind;

typedef enum AST_Kind{
  AK_None,
  AK_BaseType,
  AK_Typedef,
  AK_Enum,
  AK_Struct,
  AK_Union,
  AK_Note,
  AK_List,
  AK_Pointer,
  AK_Array,
  AK_Function,
  AK_Variable,
  AK_EnumChild,
}AST_Kind;

typedef struct AST_Node AST_Node;
struct AST_Node{
AST_Kind kind;
Token *pos;
Intern_String name;
AST_Node *next;
AST_Node *next_scope;
AST_Node *first_note;
AST_Node *last_note;
AST_Node *first_child;
AST_Node *last_child;
union {
SizeU base_type_size;
AST_Node *pointer;
AST_Node *typedef_type;
AST_Node *variable_type;
AST_Node *func_return_type;
};
};

typedef struct Parser_Error Parser_Error;
struct Parser_Error{
Parser_Error *next;
String message;
Token *token;
};

typedef struct Scope Scope;
struct Scope{
Scope *next;
AST_Node *first;
AST_Node *last;
};

typedef struct Parser Parser;
struct Parser{
Arena main_arena;
Arena intern_table_arena;
Arena symbol_table_arena;
Scope *scope_free_list;
Scope *scope_stack;
Scope *global_scope;
S64 symbols_inserted;
S64 symbols_count;
AST_Node *symbols;
Intern_String *interns;
S64 interns_in_bytes;
S64 interns_inserted;
S64 interns_count;
U8 *first_keyword;
U8 *last_keyword;
Parser_Error *first_default;
Parser_Error *last_default;

Parser_Error *first_error;
Parser_Error *last_error;

union{
Tokens token_array;
struct {
Token *tokens;
S64 len;
S64 cap;
S64 iter;
};
}
};

global String Token_Kind_metadata[] = {
[TK_End] = lit("End of stream"),
[TK_Mul] = lit("*"),
[TK_Div] = lit("/"),
[TK_Add] = lit("+"),
[TK_Sub] = lit("-"),
[TK_Mod] = lit("%"),
[TK_BitAnd] = lit("&"),
[TK_BitOr] = lit("|"),
[TK_BitXor] = lit("^"),
[TK_Neg] = lit("~"),
[TK_Not] = lit("!"),
[TK_OpenParen] = lit("("),
[TK_CloseParen] = lit(" "),
[TK_OpenBrace] = lit("{"),
[TK_CloseBrace] = lit("}"),
[TK_OpenBracket] = lit("["),
[TK_CloseBracket] = lit("]"),
[TK_Comma] = lit(","),
[TK_Pound] = lit("#"),
[TK_Question] = lit("?"),
[TK_ThreeDots] = lit("..."),
[TK_Semicolon] = lit(";"),
[TK_Dot] = lit("."),
[TK_LesserThen] = lit("<"),
[TK_GreaterThen] = lit(">"),
[TK_Colon] = lit(":"),
[TK_Assign] = lit("="),
[TK_DivAssign] = lit("/="),
[TK_MulAssign] = lit("*="),
[TK_ModAssign] = lit("%="),
[TK_SubAssign] = lit("-="),
[TK_AddAssign] = lit("+="),
[TK_AndAssign] = lit("&="),
[TK_OrAssign] = lit("|="),
[TK_XorAssign] = lit("^="),
[TK_LeftShiftAssign] = lit("<<="),
[TK_RightShiftAssign] = lit(">>="),
[TK_DoubleColon] = lit("::"),
[TK_At] = lit("@"),
[TK_Decrement] = lit("--"),
[TK_Increment] = lit("++"),
[TK_PostDecrement] = lit("--"),
[TK_PostIncrement] = lit("++"),
[TK_LesserThenOrEqual] = lit("<="),
[TK_GreaterThenOrEqual] = lit(">="),
[TK_Equals] = lit("=="),
[TK_And] = lit("&&"),
[TK_Or] = lit("||"),
[TK_NotEquals] = lit("!="),
[TK_LeftShift] = lit("<<"),
[TK_RightShift] = lit(">>"),
[TK_Arrow] = lit("->"),
[TK_ExprSizeof] = lit("sizeof"),
[TK_DocComment] = lit("DocComment"),
[TK_Comment] = lit("Comment"),
[TK_Identifier] = lit("Identifier"),
[TK_StringLit] = lit("StringLit"),
[TK_U8Lit] = lit("U8Lit"),
[TK_Character] = lit("Character"),
[TK_Error] = lit("Error"),
[TK_Float] = lit("Float"),
[TK_Int] = lit("Int"),
[TK_Keyword] = lit("Keyword"),
};
function
 Token*Tokens_array_push_empty(Tokens*a){
if(a->cap==0){
a->cap=1024;
a->tokens=malloc(sizeof(Token)*a->cap);
}
else if(a->len+1>a->cap){
a->cap*=2;
a->tokens=realloc(a->tokens,sizeof(Token)*a->cap);
}
Token*result=a->tokens+a->len++;
memory_zero(result,sizeof(*result));
return result;
}
global String Expr_Kind_metadata[] = {
[EK_None] = lit("None"),
[EK_Atom] = lit("Atom"),
[EK_Unary] = lit("Unary"),
[EK_Binary] = lit("Binary"),
[EK_Ternary] = lit("Ternary"),
[EK_Cast] = lit("Cast"),
[EK_List] = lit("List"),
[EK_Call] = lit("Call"),
[EK_Index] = lit("Index"),
};
global String AST_Kind_metadata[] = {
[AK_None] = lit("None"),
[AK_BaseType] = lit("BaseType"),
[AK_Typedef] = lit("Typedef"),
[AK_Enum] = lit("Enum"),
[AK_Struct] = lit("Struct"),
[AK_Union] = lit("Union"),
[AK_Note] = lit("Note"),
[AK_List] = lit("List"),
[AK_Pointer] = lit("Pointer"),
[AK_Array] = lit("Array"),
[AK_Function] = lit("Function"),
[AK_Variable] = lit("Variable"),
[AK_EnumChild] = lit("EnumChild"),
};
function
 void parser_default_push(Parser*parent,Parser_Error*child){
if(parent->first==0){
parent->first=parent->last=child;
}
else{
parent->last=parent->last->next=child;
}
}
function
 Parser_Error*parser_default_pop_first(Parser*parent){
if(parent->first==parent->last){
Parser_Error*node=parent->first;
parent->first=parent->last=0;
return node;
}
else if(parent->first){
Parser_Error*node=parent->first;
parent->first=parent->first->next;
}
return 0;
}

function
 void parser_error_push(Parser*parent,Parser_Error*child){
if(parent->first_error==0){
parent->first_error=parent->last_error=child;
}
else{
parent->last_error=parent->last_error->next_error=child;
}
}
function
 Parser_Error*parser_error_pop_first(Parser*parent){
if(parent->first_error==parent->last_error){
Parser_Error*node=parent->first_error;
parent->first_error=parent->last_error=0;
return node;
}
else if(parent->first_error){
Parser_Error*node=parent->first_error;
parent->first_error=parent->first_error->next_error;
}
return 0;
}

function
 Token*Parser_array_push_empty(Parser*a){
if(a->cap==0){
a->cap=1024;
a->tokens=malloc(sizeof(Token)*a->cap);
}
else if(a->len+1>a->cap){
a->cap*=2;
a->tokens=realloc(a->tokens,sizeof(Token)*a->cap);
}
Token*result=a->tokens+a->len++;
memory_zero(result,sizeof(*result));
return result;
}