path: root/src/sim86/libs/metadesk/md.h

// LICENSE AT END OF FILE (MIT).

/*
** Welcome to Metadesk!
** 
** Metadesk is a data description language designed to look like a programming
** language, and this is the accompanying parser library. While you are free to
** use it however you see fit, here are a couple of the uses we have intended
** to support:
**  + quickly writing a C or C++ metaprogram from scratch
**  + building "low budget" domain specific languages, such as marked-up
**    webpage content, or asset metadata
**  + creating robust and flexible config systems for applications
** 
** If it's your first time with Metadesk, check out the "How to Build" section
** below, and consider looking at the examples included with the library. The
** examples_directory.txt will help you find your way from the intro examples
** through all the more advanced aspects of the library you might like to
** learn about.
**
** Direct issues, questions, suggestions, requests, etc to:
** https://github.com/Dion-Systems/metadesk
** 
**
** How To Build:
**
** The library is set up as a direct source-include library, so if you have a
** single unit build you can just #include "md.h" and "md.c". If you have a
** multiple unit build you can #include "md.h" where necessary and add "md.c"
** as a separate compilation unit (extra care has to be taken if you intend to
** use overrides in a multiple unit build).
**
** See `bin/compile_flags.txt` for the flags to build with.
**
** The tests and examples can be built with the bash scripts in bin. There are
** a few things to know to use these scripts:
**  1. First you should run `bld_init.sh` which will initialize your copy of
**     Metadesk's build system.
**  2. On Linux the shell scripts should work as written. On Windows you will
**     need to use a bash interpreter specifically. Generally the `bash.exe`
**     that comes with an install of git on Windows works well for this.
**     Add it to your path or setup a batch script that calls it and then
**     pass the bash scripts to the interpreter to build.
**  3. You should be able to run the scripts:
**      `build_tests.sh`
**      `build_examples.sh`
**      `run_tests.sh`
**      `run_examples.sh`
**      `type_metadata_example.sh`
*/

#ifndef MD_H
#define MD_H

#define MD_VERSION_MAJ 1
#define MD_VERSION_MIN 0

//~ Set default values for controls
#if !defined(MD_DEFAULT_BASIC_TYPES)
# define MD_DEFAULT_BASIC_TYPES 1
#endif
#if !defined(MD_DEFAULT_MEMSET)
# define MD_DEFAULT_MEMSET 1
#endif
#if !defined(MD_DEFAULT_FILE_LOAD)
# define MD_DEFAULT_FILE_LOAD 1
#endif
#if !defined(MD_DEFAULT_FILE_ITER)
# define MD_DEFAULT_FILE_ITER 1
#endif
#if !defined(MD_DEFAULT_MEMORY)
# define MD_DEFAULT_MEMORY 1
#endif
#if !defined(MD_DEFAULT_ARENA)
# define MD_DEFAULT_ARENA 1
#endif
#if !defined(MD_DEFAULT_SCRATCH)
# define MD_DEFAULT_SCRATCH 1
#endif
#if !defined(MD_DEFAULT_SPRINTF)
# define MD_DEFAULT_SPRINTF 1
#endif

#if !defined(MD_DISABLE_PRINT_HELPERS)
# define MD_DISABLE_PRINT_HELPERS 0
#endif


//~/////////////////////////////////////////////////////////////////////////////
////////////////////////////// Context Cracking ////////////////////////////////
////////////////////////////////////////////////////////////////////////////////

#if defined(__clang__)

# define MD_COMPILER_CLANG 1

# if defined(__APPLE__) && defined(__MACH__)
#  define MD_OS_MAC 1
# elif defined(__gnu_linux__)
#  define MD_OS_LINUX 1
# elif defined(_WIN32)
#  define MD_OS_WINDOWS 1
# else
#  error This compiler/platform combo is not supported yet
# endif

# if defined(__amd64__) || defined(__amd64) || defined(__x86_64__) || defined(__x86_64)
#  define MD_ARCH_X64 1
# elif defined(i386) || defined(__i386) || defined(__i386__)
#  define MD_ARCH_X86 1
# elif defined(__aarch64__)
#  define MD_ARCH_ARM64 1
# elif defined(__arm__)
#  define MD_ARCH_ARM32 1
# else
#  error architecture not supported yet
# endif

#elif defined(_MSC_VER)

# define MD_COMPILER_CL 1

# if defined(_WIN32)
#  define MD_OS_WINDOWS 1
# else
#  error This compiler/platform combo is not supported yet
# endif

# if defined(_M_AMD64)
#  define MD_ARCH_X64 1
# elif defined(_M_IX86)
#  define MD_ARCH_X86 1
# elif defined(_M_ARM64)
#  define MD_ARCH_ARM64 1
# elif defined(_M_ARM)
#  define MD_ARCH_ARM32 1
# else
#  error architecture not supported yet
# endif

# if _MSC_VER >= 1920
#  define MD_COMPILER_CL_YEAR 2019
# elif _MSC_VER >= 1910
#  define MD_COMPILER_CL_YEAR 2017
# elif _MSC_VER >= 1900
#  define MD_COMPILER_CL_YEAR 2015
# elif _MSC_VER >= 1800
#  define MD_COMPILER_CL_YEAR 2013
# elif _MSC_VER >= 1700
#  define MD_COMPILER_CL_YEAR 2012
# elif _MSC_VER >= 1600
#  define MD_COMPILER_CL_YEAR 2010
# elif _MSC_VER >= 1500
#  define MD_COMPILER_CL_YEAR 2008
# elif _MSC_VER >= 1400
#  define MD_COMPILER_CL_YEAR 2005
# else
#  define MD_COMPILER_CL_YEAR 0
# endif

#elif defined(__GNUC__) || defined(__GNUG__)

# define MD_COMPILER_GCC 1

# if defined(__gnu_linux__)
#  define MD_OS_LINUX 1
# else
#  error This compiler/platform combo is not supported yet
# endif

# if defined(__amd64__) || defined(__amd64) || defined(__x86_64__) || defined(__x86_64)
#  define MD_ARCH_X64 1
# elif defined(i386) || defined(__i386) || defined(__i386__)
#  define MD_ARCH_X86 1
# elif defined(__aarch64__)
#  define MD_ARCH_ARM64 1
# elif defined(__arm__)
#  define MD_ARCH_ARM32 1
# else
#  error architecture not supported yet
# endif

#else
# error This compiler is not supported yet
#endif

#if defined(MD_ARCH_X64)
# define MD_ARCH_64BIT 1
#elif defined(MD_ARCH_X86)
# define MD_ARCH_32BIT 1
#endif

#if defined(__cplusplus)
# define MD_LANG_CPP 1

// We can't get this 100% correct thanks to Microsoft's compiler.
// So this check lets us pre-define MD_CPP_VERSION if we have to.
# if !defined(MD_CPP_VERSION)
#  if defined(MD_COMPILER_CL)
// CL is annoying and didn't update __cplusplus over time
// If it is available _MSVC_LANG serves the same role
#   if defined(_MSVC_LANG)
#    if _MSVC_LANG <= 199711L
#     define MD_CPP_VERSION 98
#    elif _MSVC_LANG <= 201103L
#     define MD_CPP_VERSION 11
#    elif _MSVC_LANG <= 201402L
#     define MD_CPP_VERSION 14
#    elif _MSVC_LANG <= 201703L
#     define MD_CPP_VERSION 17
#    elif _MSVC_LANG <= 202002L
#     define MD_CPP_VERSION 20
#    else
#     define MD_CPP_VERSION 23
#    endif
// If we don't have _MSVC_LANG we can guess from the compiler version
#   else
#    if MD_COMPILER_CL_YEAR <= 2010
#     define MD_CPP_VERSION 98
#    elif MD_COMPILER_CL_YEAR <= 2015
#     define MD_CPP_VERSION 11
#    else
#     define MD_CPP_VERSION 17
#    endif
#   endif
#  else
// Other compilers use __cplusplus correctly
#   if __cplusplus <= 199711L
#    define MD_CPP_VERSION 98
#   elif __cplusplus <= 201103L
#    define MD_CPP_VERSION 11
#   elif __cplusplus <= 201402L
#    define MD_CPP_VERSION 14
#   elif __cplusplus <= 201703L
#    define MD_CPP_VERSION 17
#   elif __cplusplus <= 202002L
#    define MD_CPP_VERSION 20
#   else
#    define MD_CPP_VERSION 23
#   endif
#  endif
# endif

#else
# define MD_LANG_C 1
#endif

// zeroify

#if !defined(MD_ARCH_32BIT)
# define MD_ARCH_32BIT 0
#endif
#if !defined(MD_ARCH_64BIT)
# define MD_ARCH_64BIT 0
#endif
#if !defined(MD_ARCH_X64)
# define MD_ARCH_X64 0
#endif
#if !defined(MD_ARCH_X86)
# define MD_ARCH_X86 0
#endif
#if !defined(MD_ARCH_ARM64)
# define MD_ARCH_ARM64 0
#endif
#if !defined(MD_ARCH_ARM32)
# define MD_ARCH_ARM32 0
#endif
#if !defined(MD_COMPILER_CL)
# define MD_COMPILER_CL 0
#endif
#if !defined(MD_COMPILER_GCC)
# define MD_COMPILER_GCC 0
#endif
#if !defined(MD_COMPILER_CLANG)
# define MD_COMPILER_CLANG 0
#endif
#if !defined(MD_OS_WINDOWS)
# define MD_OS_WINDOWS 0
#endif
#if !defined(MD_OS_LINUX)
# define MD_OS_LINUX 0
#endif
#if !defined(MD_OS_MAC)
# define MD_OS_MAC 0
#endif
#if !defined(MD_LANG_C)
# define MD_LANG_C 0
#endif
#if !defined(MD_LANG_CPP)
# define MD_LANG_CPP 0
#endif
#if !defined(MD_CPP_VERSION)
# define MD_CPP_VERSION 0
#endif

#if MD_LANG_CPP
# define MD_ZERO_STRUCT {}
#else
# define MD_ZERO_STRUCT {0}
#endif

#if MD_LANG_C
# define MD_C_LINKAGE_BEGIN
# define MD_C_LINKAGE_END
#else
# define MD_C_LINKAGE_BEGIN extern "C"{
# define MD_C_LINKAGE_END }
#endif

#if MD_COMPILER_CL
# define MD_THREAD_LOCAL __declspec(thread)
#elif MD_COMPILER_GCC || MD_COMPILER_CLANG
# define MD_THREAD_LOCAL __thread
#endif

//~/////////////////////////////////////////////////////////////////////////////
///////////////////////////// Helpers, Macros, Etc /////////////////////////////
////////////////////////////////////////////////////////////////////////////////

//~ Linkage Wrappers

#if !defined(MD_FUNCTION)
# define MD_FUNCTION
#endif

#if !defined(MD_GLOBAL)
# define MD_GLOBAL static
#endif

//~ Basic Utilities

#define MD_Assert(c) if (!(c)) { *(volatile MD_u64 *)0 = 0; }
#define MD_StaticAssert(c,label) MD_u8 MD_static_assert_##label[(c)?(1):(-1)]
#define MD_ArrayCount(a) (sizeof(a) / sizeof((a)[0]))

#define MD_Min(a,b) (((a)<(b))?(a):(b))
#define MD_Max(a,b) (((a)>(b))?(a):(b))
#define MD_ClampBot(a,b) MD_Max(a,b)
#define MD_ClampTop(a,b) MD_Min(a,b)

#define MD_AlignPow2(x,b) (((x)+((b)-1))&(~((b)-1)))

//~ Linked List Macros

// terminator modes
#define MD_CheckNull(p) ((p)==0)
#define MD_SetNull(p) ((p)=0)
#define MD_CheckNil(p) (MD_NodeIsNil(p))
#define MD_SetNil(p) ((p)=MD_NilNode())

// implementations
#define MD_QueuePush_NZ(f,l,n,next,zchk,zset) (zchk(f)?\
(f)=(l)=(n):\
((l)->next=(n),(l)=(n),zset((n)->next)))
#define MD_QueuePop_NZ(f,l,next,zset) ((f)==(l)?\
(zset(f),zset(l)):\
((f)=(f)->next))
#define MD_StackPush_N(f,n,next) ((n)->next=(f),(f)=(n))
#define MD_StackPop_NZ(f,next,zchk) (zchk(f)?0:(f)=(f)->next)

#define MD_DblPushBack_NPZ(f,l,n,next,prev,zchk,zset) \
(zchk(f)?\
((f)=(l)=(n),zset((n)->next),zset((n)->prev)):\
((n)->prev=(l),(l)->next=(n),(l)=(n),zset((n)->next)))
#define MD_DblRemove_NPZ(f,l,n,next,prev,zset) (((f)==(n)?\
((f)=(f)->next,zset((f)->prev)):\
(l)==(n)?\
((l)=(l)->prev,zset((l)->next)):\
((n)->next->prev=(n)->prev,\
(n)->prev->next=(n)->next)))

// compositions
#define MD_QueuePush(f,l,n) MD_QueuePush_NZ(f,l,n,next,MD_CheckNull,MD_SetNull)
#define MD_QueuePop(f,l)    MD_QueuePop_NZ(f,l,next,MD_SetNull)
#define MD_StackPush(f,n)   MD_StackPush_N(f,n,next)
#define MD_StackPop(f)      MD_StackPop_NZ(f,next,MD_CheckNull)
#define MD_DblPushBack(f,l,n)  MD_DblPushBack_NPZ(f,l,n,next,prev,MD_CheckNull,MD_SetNull)
#define MD_DblPushFront(f,l,n) MD_DblPushBack_NPZ(l,f,n,prev,next,MD_CheckNull,MD_SetNull)
#define MD_DblRemove(f,l,n)    MD_DblRemove_NPZ(f,l,n,next,prev,MD_SetNull)

#define MD_NodeDblPushBack(f,l,n)  MD_DblPushBack_NPZ(f,l,n,next,prev,MD_CheckNil,MD_SetNil)
#define MD_NodeDblPushFront(f,l,n) MD_DblPushBack_NPZ(l,f,n,prev,next,MD_CheckNil,MD_SetNil)
#define MD_NodeDblRemove(f,l,n)    MD_DblRemove_NPZ(f,l,n,next,prev,MD_SetNil)


//~ Memory Operations

#define MD_MemorySet(p,v,z)    (MD_IMPL_Memset(p,v,z))
#define MD_MemoryZero(p,z)     (MD_IMPL_Memset(p,0,z))
#define MD_MemoryZeroStruct(p) (MD_IMPL_Memset(p,0,sizeof(*(p))))
#define MD_MemoryCopy(d,s,z)   (MD_IMPL_Memmove(d,s,z))

//~ sprintf
#if MD_DEFAULT_SPRINTF
#define STB_SPRINTF_DECORATE(name) md_stbsp_##name
#define MD_IMPL_Vsnprintf md_stbsp_vsnprintf
#include "md_stb_sprintf.h"
#endif

//~/////////////////////////////////////////////////////////////////////////////
//////////////////////////////////// Types /////////////////////////////////////
////////////////////////////////////////////////////////////////////////////////

//~ Basic Types

#include <stdarg.h>

#if defined(MD_DEFAULT_BASIC_TYPES)

#include <stdint.h>
typedef int8_t   MD_i8;
typedef int16_t  MD_i16;
typedef int32_t  MD_i32;
typedef int64_t  MD_i64;
typedef uint8_t  MD_u8;
typedef uint16_t MD_u16;
typedef uint32_t MD_u32;
typedef uint64_t MD_u64;
typedef float    MD_f32;
typedef double   MD_f64;

#endif

typedef MD_i8  MD_b8;
typedef MD_i16 MD_b16;
typedef MD_i32 MD_b32;
typedef MD_i64 MD_b64;

//~ Default Arena

#if MD_DEFAULT_ARENA

typedef struct MD_ArenaDefault MD_ArenaDefault;
struct MD_ArenaDefault
{
    MD_ArenaDefault *prev;
    MD_ArenaDefault *current;
    MD_u64 base_pos;
    MD_u64 pos;
    MD_u64 cmt;
    MD_u64 cap;
    MD_u64 align;
};
#define MD_IMPL_Arena MD_ArenaDefault

#endif

//~ Abstract Arena

#if !defined(MD_IMPL_Arena)
# error Missing implementation for MD_IMPL_Arena
#endif

typedef MD_IMPL_Arena MD_Arena;

//~ Arena Helpers

typedef struct MD_ArenaTemp MD_ArenaTemp;
struct MD_ArenaTemp
{
    MD_Arena *arena;
    MD_u64 pos;
};

//~ Basic Unicode string types.

typedef struct MD_String8 MD_String8;
struct MD_String8
{
    MD_u8 *str;
    MD_u64 size;
};

typedef struct MD_String16 MD_String16;
struct MD_String16
{
    MD_u16 *str;
    MD_u64 size;
};

typedef struct MD_String32 MD_String32;
struct MD_String32
{
    MD_u32 *str;
    MD_u64 size;
};

typedef struct MD_String8Node MD_String8Node;
struct MD_String8Node
{
    MD_String8Node *next;
    MD_String8 string;
};

typedef struct MD_String8List MD_String8List;
struct MD_String8List
{
    MD_u64 node_count;
    MD_u64 total_size;
    MD_String8Node *first;
    MD_String8Node *last;
};

typedef struct MD_StringJoin MD_StringJoin;
struct MD_StringJoin
{
    MD_String8 pre;
    MD_String8 mid;
    MD_String8 post;
};

// NOTE(rjf): @maintenance These three flag types must not overlap.
typedef MD_u32 MD_MatchFlags;
typedef MD_u32 MD_StringMatchFlags;
typedef MD_u32 MD_NodeMatchFlags;
enum
{
    MD_MatchFlag_FindLast = (1<<0),
};
enum
{
    MD_StringMatchFlag_CaseInsensitive  = (1<<4),
    MD_StringMatchFlag_RightSideSloppy  = (1<<5),
    MD_StringMatchFlag_SlashInsensitive = (1<<6),
};
enum
{
    MD_NodeMatchFlag_Tags             = (1<<16),
    MD_NodeMatchFlag_TagArguments     = (1<<17),
    MD_NodeMatchFlag_NodeFlags        = (1<<18),
};

typedef struct MD_DecodedCodepoint MD_DecodedCodepoint;
struct MD_DecodedCodepoint
{
    MD_u32 codepoint;
    MD_u32 advance;
};

typedef enum MD_IdentifierStyle
{
    MD_IdentifierStyle_UpperCamelCase,
    MD_IdentifierStyle_LowerCamelCase,
    MD_IdentifierStyle_UpperCase,
    MD_IdentifierStyle_LowerCase,
}
MD_IdentifierStyle;

//~ Node types that are used to build all ASTs.

typedef enum MD_NodeKind
{
    // NOTE(rjf): @maintenance Must be kept in sync with MD_StringFromNodeKind.
    
    MD_NodeKind_Nil,
    
    // NOTE(rjf): Generated by parser
    MD_NodeKind_File,
    MD_NodeKind_ErrorMarker,
    
    // NOTE(rjf): Parsed from user Metadesk code
    MD_NodeKind_Main,
    MD_NodeKind_Tag,
    
    // NOTE(rjf): User-created data structures
    MD_NodeKind_List,
    MD_NodeKind_Reference,
    
    MD_NodeKind_COUNT,
}
MD_NodeKind;

typedef enum MD_NodeFlags MD_NodeFlags;
#define MD_NodeFlag_AfterFromBefore(f) ((f) << 1)

enum MD_NodeFlags
{
    // NOTE(rjf): @maintenance Must be kept in sync with MD_StringListFromNodeFlags.
    
    // NOTE(rjf): @maintenance Because of MD_NodeFlag_AfterFromBefore, it is
    // *required* that every single pair of "Before*" or "After*" flags be in
    // the correct order which is that the Before* flag comes first, and the
    // After* flag comes immediately after (After* being the more significant
    // bit).
    
    MD_NodeFlag_HasParenLeft               = (1<<0),
    MD_NodeFlag_HasParenRight              = (1<<1),
    MD_NodeFlag_HasBracketLeft             = (1<<2),
    MD_NodeFlag_HasBracketRight            = (1<<3),
    MD_NodeFlag_HasBraceLeft               = (1<<4),
    MD_NodeFlag_HasBraceRight              = (1<<5),
    
    MD_NodeFlag_MaskSetDelimiters          = (0x3F<<0),
    
    MD_NodeFlag_IsBeforeSemicolon          = (1<<6),
    MD_NodeFlag_IsAfterSemicolon           = (1<<7),
    MD_NodeFlag_IsBeforeComma              = (1<<8),
    MD_NodeFlag_IsAfterComma               = (1<<9),
    
    MD_NodeFlag_MaskSeperators             = (0xF<<6),
    
    MD_NodeFlag_StringSingleQuote       = (1<<10),
    MD_NodeFlag_StringDoubleQuote       = (1<<11),
    MD_NodeFlag_StringTick              = (1<<12),
    MD_NodeFlag_StringTriplet           = (1<<13),
    
    MD_NodeFlag_MaskStringDelimiters    = (0xF<<10),
    
    MD_NodeFlag_Numeric                 = (1<<14),
    MD_NodeFlag_Identifier              = (1<<15),
    MD_NodeFlag_StringLiteral           = (1<<16),
    MD_NodeFlag_Symbol                  = (1<<17),
    
    MD_NodeFlag_MaskLabelKind           = (0xF<<14),
};

typedef struct MD_Node MD_Node;
struct MD_Node
{
    // Tree relationship data.
    MD_Node *next;
    MD_Node *prev;
    MD_Node *parent;
    MD_Node *first_child;
    MD_Node *last_child;
    
    // Tag list.
    MD_Node *first_tag;
    MD_Node *last_tag;
    
    // Node info.
    MD_NodeKind kind;
    MD_NodeFlags flags;
    MD_String8 string;
    MD_String8 raw_string;
    
    // Source code location information.
    MD_u64 offset;
    
    // Reference.
    MD_Node *ref_target;
    
    // Comments.
    // @usage prev_comment/next_comment should be considered "hidden". Rely on
    // the functions MD_PrevCommentFromNode/MD_NextCommentFromNode to access
    // these. Directly access to these is likely to break in a future version.
    MD_String8 prev_comment;
    MD_String8 next_comment;
};

//~ Code Location Info.

typedef struct MD_CodeLoc MD_CodeLoc;
struct MD_CodeLoc
{
    MD_String8 filename;
    MD_u32 line;
    MD_u32 column;
};

//~ String-To-Ptr and Ptr-To-Ptr tables

typedef struct MD_MapKey MD_MapKey;
struct MD_MapKey
{
    MD_u64 hash;
    MD_u64 size;
    void *ptr;
};

typedef struct MD_MapSlot MD_MapSlot;
struct MD_MapSlot
{
    MD_MapSlot *next;
    MD_MapKey key;
    void *val;
};

typedef struct MD_MapBucket MD_MapBucket;
struct MD_MapBucket
{
    MD_MapSlot *first;
    MD_MapSlot *last;
};

typedef struct MD_Map MD_Map;
struct MD_Map
{
    MD_MapBucket *buckets;
    MD_u64 bucket_count;
};

//~ Tokens

typedef MD_u32 MD_TokenKind;
enum
{
    MD_TokenKind_Identifier          = (1<<0),
    MD_TokenKind_Numeric             = (1<<1),
    MD_TokenKind_StringLiteral       = (1<<2),
    MD_TokenKind_Symbol              = (1<<3),
    MD_TokenKind_Reserved            = (1<<4),
    MD_TokenKind_Comment             = (1<<5),
    MD_TokenKind_Whitespace          = (1<<6),
    MD_TokenKind_Newline             = (1<<7),
    MD_TokenKind_BrokenComment       = (1<<8),
    MD_TokenKind_BrokenStringLiteral = (1<<9),
    MD_TokenKind_BadCharacter        = (1<<10),
};

typedef MD_u32 MD_TokenGroups;
enum
{
    MD_TokenGroup_Comment = MD_TokenKind_Comment,
    MD_TokenGroup_Whitespace = (MD_TokenKind_Whitespace|
                                MD_TokenKind_Newline),
    MD_TokenGroup_Irregular = (MD_TokenGroup_Comment|
                               MD_TokenGroup_Whitespace),
    MD_TokenGroup_Regular = ~MD_TokenGroup_Irregular,
    MD_TokenGroup_Label   = (MD_TokenKind_Identifier|
                             MD_TokenKind_Numeric|
                             MD_TokenKind_StringLiteral|
                             MD_TokenKind_Symbol),
    MD_TokenGroup_Error   = (MD_TokenKind_BrokenComment|
                             MD_TokenKind_BrokenStringLiteral|
                             MD_TokenKind_BadCharacter),
};

typedef struct MD_Token MD_Token;
struct MD_Token
{
    MD_TokenKind kind;
    MD_NodeFlags node_flags;
    MD_String8 string;
    MD_String8 raw_string;
};

//~ Parsing State

typedef enum MD_MessageKind
{
    // NOTE(rjf): @maintenance This enum needs to be sorted in order of
    // severity.
    MD_MessageKind_Null,
    MD_MessageKind_Note,
    MD_MessageKind_Warning,
    MD_MessageKind_Error,
    MD_MessageKind_FatalError,
}
MD_MessageKind;

typedef struct MD_Message MD_Message;
struct MD_Message
{
    MD_Message *next;
    MD_Node *node;
    MD_MessageKind kind;
    MD_String8 string;
    void *user_ptr;
};

typedef struct MD_MessageList MD_MessageList;
struct MD_MessageList
{
    MD_MessageKind max_message_kind;
    // TODO(allen): rename
    MD_u64 node_count;
    MD_Message *first;
    MD_Message *last;
};

typedef enum MD_ParseSetRule
{
    MD_ParseSetRule_EndOnDelimiter,
    MD_ParseSetRule_Global,
} MD_ParseSetRule;

typedef struct MD_ParseResult MD_ParseResult;
struct MD_ParseResult
{
    MD_Node *node;
    MD_u64 string_advance;
    MD_MessageList errors;
};

//~ Expression Parsing

typedef enum MD_ExprOprKind
{
    MD_ExprOprKind_Null,
    MD_ExprOprKind_Prefix,
    MD_ExprOprKind_Postfix,
    MD_ExprOprKind_Binary,
    MD_ExprOprKind_BinaryRightAssociative,
    MD_ExprOprKind_COUNT,
} MD_ExprOprKind;

typedef struct MD_ExprOpr MD_ExprOpr;
struct MD_ExprOpr
{
    struct MD_ExprOpr *next;
    MD_u32 op_id;
    MD_ExprOprKind kind;
    MD_u32 precedence;
    MD_String8 string;
    void *op_ptr;
};

typedef struct MD_ExprOprList MD_ExprOprList;
struct MD_ExprOprList
{
    MD_ExprOpr *first;
    MD_ExprOpr *last;
    MD_u64 count;
};

typedef struct MD_ExprOprTable MD_ExprOprTable;
struct MD_ExprOprTable
{
    // TODO(mal): @upgrade_potential Hash?
    MD_ExprOprList table[MD_ExprOprKind_COUNT];
};

typedef struct MD_Expr MD_Expr;
struct MD_Expr
{
    struct MD_Expr *parent;
    union
    {
        struct MD_Expr *left;
        struct MD_Expr *unary_operand;
    };
    struct MD_Expr *right;
    MD_ExprOpr *op;
    MD_Node *md_node;
};

typedef struct MD_ExprParseResult MD_ExprParseResult;
struct MD_ExprParseResult
{
    MD_Expr *expr;
    MD_MessageList errors;
};

// TODO(allen): nil MD_Expr

typedef struct MD_ExprParseCtx MD_ExprParseCtx;
struct MD_ExprParseCtx
{
    MD_ExprOprTable *op_table;
    
#define MD_POSTFIX_SETLIKE_OP_COUNT 5   // (), [], {}, [), (]
    struct
    {
        MD_ExprOpr *postfix_set_ops[MD_POSTFIX_SETLIKE_OP_COUNT];
        MD_NodeFlags postfix_set_flags[MD_POSTFIX_SETLIKE_OP_COUNT];
    } accel;
#undef MD_POSTFIX_SETLIKE_OP_COUNT
    
    MD_MessageList errors;
};

typedef void (*MD_BakeOperatorErrorHandler)(MD_MessageKind kind, MD_String8 s);

//~ String Generation Types

typedef MD_u32 MD_GenerateFlags;
enum
{
    MD_GenerateFlag_Tags         = (1<<0),
    MD_GenerateFlag_TagArguments = (1<<1),
    MD_GenerateFlag_Children     = (1<<2),
    MD_GenerateFlag_Comments     = (1<<3),
    MD_GenerateFlag_NodeKind     = (1<<4),
    MD_GenerateFlag_NodeFlags    = (1<<5),
    MD_GenerateFlag_Location     = (1<<6),
    
    MD_GenerateFlags_Tree = (MD_GenerateFlag_Tags |
                             MD_GenerateFlag_TagArguments |
                             MD_GenerateFlag_Children),
    MD_GenerateFlags_All  = 0xffffffff,
};

//~ Command line parsing helper types.

typedef struct MD_CmdLineOption MD_CmdLineOption;
struct MD_CmdLineOption
{
    MD_CmdLineOption *next;
    MD_String8 name;
    MD_String8List values;
};

typedef struct MD_CmdLine MD_CmdLine;
struct MD_CmdLine
{
    MD_String8List inputs;
    MD_CmdLineOption *first_option;
    MD_CmdLineOption *last_option;
};

//~ File system access types.

typedef MD_u32 MD_FileFlags;
enum
{
    MD_FileFlag_Directory = (1<<0),
};

typedef struct MD_FileInfo MD_FileInfo;
struct MD_FileInfo
{
    MD_FileFlags flags;
    MD_String8 filename;
    MD_u64 file_size;
};

typedef struct MD_FileIter MD_FileIter;
struct MD_FileIter
{
    // This is opaque state to store OS-specific file-system iteration data.
    MD_u8 opaque[640];
};

//~/////////////////////////////////////////////////////////////////////////////
////////////////////////////////// Functions ///////////////////////////////////
////////////////////////////////////////////////////////////////////////////////

//~ Arena

MD_FUNCTION MD_Arena*    MD_ArenaAlloc(void);
MD_FUNCTION void         MD_ArenaRelease(MD_Arena *arena);

MD_FUNCTION void*        MD_ArenaPush(MD_Arena *arena, MD_u64 size);
MD_FUNCTION void         MD_ArenaPutBack(MD_Arena *arena, MD_u64 size);
MD_FUNCTION void         MD_ArenaSetAlign(MD_Arena *arena, MD_u64 boundary);
MD_FUNCTION void         MD_ArenaPushAlign(MD_Arena *arena, MD_u64 boundary);
MD_FUNCTION void         MD_ArenaClear(MD_Arena *arena);

#define MD_PushArray(a,T,c) (T*)(MD_ArenaPush((a), sizeof(T)*(c)))
#define MD_PushArrayZero(a,T,c) (T*)(MD_MemoryZero(MD_PushArray(a,T,c), sizeof(T)*(c)))

MD_FUNCTION MD_ArenaTemp MD_ArenaBeginTemp(MD_Arena *arena);
MD_FUNCTION void         MD_ArenaEndTemp(MD_ArenaTemp temp);

//~ Arena Scratch Pool

MD_FUNCTION MD_ArenaTemp MD_GetScratch(MD_Arena **conflicts, MD_u64 count);

#define MD_ReleaseScratch(scratch) MD_ArenaEndTemp(scratch)

//~ Characters

MD_FUNCTION MD_b32 MD_CharIsAlpha(MD_u8 c);
MD_FUNCTION MD_b32 MD_CharIsAlphaUpper(MD_u8 c);
MD_FUNCTION MD_b32 MD_CharIsAlphaLower(MD_u8 c);
MD_FUNCTION MD_b32 MD_CharIsDigit(MD_u8 c);
MD_FUNCTION MD_b32 MD_CharIsUnreservedSymbol(MD_u8 c);
MD_FUNCTION MD_b32 MD_CharIsReservedSymbol(MD_u8 c);
MD_FUNCTION MD_b32 MD_CharIsSpace(MD_u8 c);
MD_FUNCTION MD_u8  MD_CharToUpper(MD_u8 c);
MD_FUNCTION MD_u8  MD_CharToLower(MD_u8 c);
MD_FUNCTION MD_u8  MD_CharToForwardSlash(MD_u8 c);

//~ Strings

MD_FUNCTION MD_u64         MD_CalculateCStringLength(char *cstr);

MD_FUNCTION MD_String8     MD_S8(MD_u8 *str, MD_u64 size);
#define MD_S8CString(s)    MD_S8((MD_u8 *)(s), MD_CalculateCStringLength(s))

#if MD_LANG_C
# define MD_S8Lit(s)        (MD_String8){(MD_u8 *)(s), sizeof(s)-1}
#elif MD_LANG_CPP
# define MD_S8Lit(s)        MD_S8((MD_u8*)(s), sizeof(s) - 1)
#endif
#define MD_S8LitComp(s)     {(MD_u8 *)(s), sizeof(s)-1}

#if MD_CPP_VERSION != 0 && MD_CPP_VERSION != 98 // anything C++11 and up
static inline MD_String8
operator "" _md(const char *s, size_t size)
{
    MD_String8 str = MD_S8((MD_u8 *)s, (MD_u64)size);
    return str;
}
#endif

MD_FUNCTION MD_String8     MD_S8Range(MD_u8 *first, MD_u8 *opl);

MD_FUNCTION MD_String8     MD_S8Substring(MD_String8 str, MD_u64 min, MD_u64 max);
MD_FUNCTION MD_String8     MD_S8Skip(MD_String8 str, MD_u64 min);
MD_FUNCTION MD_String8     MD_S8Chop(MD_String8 str, MD_u64 nmax);
MD_FUNCTION MD_String8     MD_S8Prefix(MD_String8 str, MD_u64 size);
MD_FUNCTION MD_String8     MD_S8Suffix(MD_String8 str, MD_u64 size);

MD_FUNCTION MD_b32         MD_S8Match(MD_String8 a, MD_String8 b, MD_MatchFlags flags);
MD_FUNCTION MD_u64         MD_S8FindSubstring(MD_String8 str, MD_String8 substring,
                                              MD_u64 start_pos, MD_MatchFlags flags);

MD_FUNCTION MD_String8     MD_S8Copy(MD_Arena *arena, MD_String8 string);
MD_FUNCTION MD_String8     MD_S8FmtV(MD_Arena *arena, char *fmt, va_list args);

MD_FUNCTION MD_String8     MD_S8Fmt(MD_Arena *arena, char *fmt, ...);

#define MD_S8VArg(s) (int)(s).size, (s).str

MD_FUNCTION void           MD_S8ListPush(MD_Arena *arena, MD_String8List *list,
                                         MD_String8 string);
MD_FUNCTION void           MD_S8ListPushFmt(MD_Arena *arena, MD_String8List *list,
                                            char *fmt, ...);

MD_FUNCTION void           MD_S8ListConcat(MD_String8List *list, MD_String8List *to_push);
MD_FUNCTION MD_String8List MD_S8Split(MD_Arena *arena, MD_String8 string, int splitter_count,
                                      MD_String8 *splitters);
MD_FUNCTION MD_String8     MD_S8ListJoin(MD_Arena *arena, MD_String8List list,
                                         MD_StringJoin *join);
MD_FUNCTION MD_String8     MD_S8ListJoinMid(MD_Arena *arena, MD_String8List list,
                                            MD_String8 mid_separator);

MD_FUNCTION MD_String8     MD_S8Stylize(MD_Arena *arena, MD_String8 string,
                                        MD_IdentifierStyle style, MD_String8 separator);

//~ Unicode Conversions

MD_FUNCTION MD_DecodedCodepoint MD_DecodeCodepointFromUtf8(MD_u8 *str, MD_u64 max);
MD_FUNCTION MD_DecodedCodepoint MD_DecodeCodepointFromUtf16(MD_u16 *str, MD_u64 max);
MD_FUNCTION MD_u32         MD_Utf8FromCodepoint(MD_u8 *out, MD_u32 codepoint);
MD_FUNCTION MD_u32         MD_Utf16FromCodepoint(MD_u16 *out, MD_u32 codepoint);
MD_FUNCTION MD_String8     MD_S8FromS16(MD_Arena *arena, MD_String16 str);
MD_FUNCTION MD_String16    MD_S16FromS8(MD_Arena *arena, MD_String8 str);
MD_FUNCTION MD_String8     MD_S8FromS32(MD_Arena *arena, MD_String32 str);
MD_FUNCTION MD_String32    MD_S32FromS8(MD_Arena *arena, MD_String8 str);

//~ String Skipping/Chopping Helpers

// This is intended for removing extensions.
MD_FUNCTION MD_String8 MD_PathChopLastPeriod(MD_String8 string);

// This is intended for removing everything but the filename.
MD_FUNCTION MD_String8 MD_PathSkipLastSlash(MD_String8 string);

// This is intended for getting an extension from a filename.
MD_FUNCTION MD_String8 MD_PathSkipLastPeriod(MD_String8 string);

// This is intended for getting the folder string from a full path.
MD_FUNCTION MD_String8 MD_PathChopLastSlash(MD_String8 string);

MD_FUNCTION MD_String8 MD_S8SkipWhitespace(MD_String8 string);
MD_FUNCTION MD_String8 MD_S8ChopWhitespace(MD_String8 string);

//~ Numeric Strings

MD_FUNCTION MD_b32     MD_StringIsU64(MD_String8 string, MD_u32 radix);
MD_FUNCTION MD_b32     MD_StringIsCStyleInt(MD_String8 string);

MD_FUNCTION MD_u64     MD_U64FromString(MD_String8 string, MD_u32 radix);
MD_FUNCTION MD_i64     MD_CStyleIntFromString(MD_String8 string);
MD_FUNCTION MD_f64     MD_F64FromString(MD_String8 string);

MD_FUNCTION MD_String8 MD_CStyleHexStringFromU64(MD_Arena *arena, MD_u64 x, MD_b32 caps);

//~ Enum/Flag Strings

MD_FUNCTION MD_String8     MD_StringFromNodeKind(MD_NodeKind kind);
MD_FUNCTION MD_String8List MD_StringListFromNodeFlags(MD_Arena *arena, MD_NodeFlags flags);

//~ Map Table Data Structure

MD_FUNCTION MD_u64 MD_HashStr(MD_String8 string);
MD_FUNCTION MD_u64 MD_HashPtr(void *p);

MD_FUNCTION MD_Map      MD_MapMakeBucketCount(MD_Arena *arena, MD_u64 bucket_count);
MD_FUNCTION MD_Map      MD_MapMake(MD_Arena *arena);
MD_FUNCTION MD_MapKey   MD_MapKeyStr(MD_String8 string);
MD_FUNCTION MD_MapKey   MD_MapKeyPtr(void *ptr);
MD_FUNCTION MD_MapSlot* MD_MapLookup(MD_Map *map, MD_MapKey key);
MD_FUNCTION MD_MapSlot* MD_MapScan(MD_MapSlot *first_slot, MD_MapKey key);
MD_FUNCTION MD_MapSlot* MD_MapInsert(MD_Arena *arena, MD_Map *map, MD_MapKey key, void *val);
MD_FUNCTION MD_MapSlot* MD_MapOverwrite(MD_Arena *arena, MD_Map *map, MD_MapKey key,
                                        void *val);

//~ Parsing

MD_FUNCTION MD_Token       MD_TokenFromString(MD_String8 string);
MD_FUNCTION MD_u64         MD_LexAdvanceFromSkips(MD_String8 string, MD_TokenKind skip_kinds);
MD_FUNCTION MD_ParseResult MD_ParseResultZero(void);
MD_FUNCTION MD_ParseResult MD_ParseNodeSet(MD_Arena *arena, MD_String8 string, MD_u64 offset, MD_Node *parent,
                                           MD_ParseSetRule rule);
MD_FUNCTION MD_ParseResult MD_ParseOneNode(MD_Arena *arena, MD_String8 string, MD_u64 offset);
MD_FUNCTION MD_ParseResult MD_ParseWholeString(MD_Arena *arena, MD_String8 filename, MD_String8 contents);

MD_FUNCTION MD_ParseResult MD_ParseWholeFile(MD_Arena *arena, MD_String8 filename);

//~ Messages (Errors/Warnings)

MD_FUNCTION MD_Node*   MD_MakeErrorMarkerNode(MD_Arena *arena, MD_String8 parse_contents,
                                              MD_u64 offset);

MD_FUNCTION MD_Message*MD_MakeNodeError(MD_Arena *arena, MD_Node *node,
                                        MD_MessageKind kind, MD_String8 str);
MD_FUNCTION MD_Message*MD_MakeTokenError(MD_Arena *arena, MD_String8 parse_contents,
                                         MD_Token token, MD_MessageKind kind,
                                         MD_String8 str);

MD_FUNCTION void       MD_MessageListPush(MD_MessageList *list, MD_Message *message);
MD_FUNCTION void       MD_MessageListConcat(MD_MessageList *list, MD_MessageList *to_push);

//~ Location Conversion

MD_FUNCTION MD_CodeLoc MD_CodeLocFromFileOffset(MD_String8 filename, MD_u8 *base, MD_u64 offset);
MD_FUNCTION MD_CodeLoc MD_CodeLocFromNode(MD_Node *node);

//~ Tree/List Building

MD_FUNCTION MD_b32   MD_NodeIsNil(MD_Node *node);
MD_FUNCTION MD_Node *MD_NilNode(void);
MD_FUNCTION MD_Node *MD_MakeNode(MD_Arena *arena, MD_NodeKind kind, MD_String8 string,
                                 MD_String8 raw_string, MD_u64 offset);
MD_FUNCTION void     MD_PushChild(MD_Node *parent, MD_Node *new_child);
MD_FUNCTION void     MD_PushTag(MD_Node *node, MD_Node *tag);

MD_FUNCTION MD_Node *MD_MakeList(MD_Arena *arena);
MD_FUNCTION void     MD_ListConcatInPlace(MD_Node *list, MD_Node *to_push);
MD_FUNCTION MD_Node *MD_PushNewReference(MD_Arena *arena, MD_Node *list, MD_Node *target);

//~ Introspection Helpers

// These calls are for getting info from nodes, and introspecting
// on trees that are returned to you by the parser.

MD_FUNCTION MD_Node *  MD_FirstNodeWithString(MD_Node *first, MD_String8 string, MD_MatchFlags flags);
MD_FUNCTION MD_Node *  MD_NodeAtIndex(MD_Node *first, int n);
MD_FUNCTION MD_Node *  MD_FirstNodeWithFlags(MD_Node *first, MD_NodeFlags flags);
MD_FUNCTION int        MD_IndexFromNode(MD_Node *node);
MD_FUNCTION MD_Node *  MD_RootFromNode(MD_Node *node);
MD_FUNCTION MD_Node *  MD_ChildFromString(MD_Node *node, MD_String8 child_string, MD_MatchFlags flags);
MD_FUNCTION MD_Node *  MD_TagFromString(MD_Node *node, MD_String8 tag_string, MD_MatchFlags flags);
MD_FUNCTION MD_Node *  MD_ChildFromIndex(MD_Node *node, int n);
MD_FUNCTION MD_Node *  MD_TagFromIndex(MD_Node *node, int n);
MD_FUNCTION MD_Node *  MD_TagArgFromIndex(MD_Node *node, MD_String8 tag_string, MD_MatchFlags flags, int n);
MD_FUNCTION MD_Node *  MD_TagArgFromString(MD_Node *node, MD_String8 tag_string, MD_MatchFlags tag_str_flags, MD_String8 arg_string, MD_MatchFlags arg_str_flags);
MD_FUNCTION MD_b32     MD_NodeHasChild(MD_Node *node, MD_String8 string, MD_MatchFlags flags);
MD_FUNCTION MD_b32     MD_NodeHasTag(MD_Node *node, MD_String8 string, MD_MatchFlags flags);
MD_FUNCTION MD_i64     MD_ChildCountFromNode(MD_Node *node);
MD_FUNCTION MD_i64     MD_TagCountFromNode(MD_Node *node);
MD_FUNCTION MD_Node *  MD_ResolveNodeFromReference(MD_Node *node);
MD_FUNCTION MD_Node*   MD_NodeNextWithLimit(MD_Node *node, MD_Node *opl);

MD_FUNCTION MD_String8 MD_PrevCommentFromNode(MD_Node *node);
MD_FUNCTION MD_String8 MD_NextCommentFromNode(MD_Node *node);

// NOTE(rjf): For-Loop Helpers
#define MD_EachNode(it, first) MD_Node *it = (first); !MD_NodeIsNil(it); it = it->next

//~ Error/Warning Helpers

MD_FUNCTION MD_String8 MD_StringFromMessageKind(MD_MessageKind kind);

#define MD_FmtCodeLoc "%.*s:%i:%i:"
#define MD_CodeLocVArg(loc) MD_S8VArg((loc).filename), (loc).line, (loc).column

MD_FUNCTION MD_String8 MD_FormatMessage(MD_Arena *arena, MD_CodeLoc loc, MD_MessageKind kind,
                                        MD_String8 string);

#if !MD_DISABLE_PRINT_HELPERS
#include <stdio.h>
MD_FUNCTION void MD_PrintMessage(FILE *file, MD_CodeLoc loc, MD_MessageKind kind,
                                 MD_String8 string);
MD_FUNCTION void MD_PrintMessageFmt(FILE *file, MD_CodeLoc code_loc, MD_MessageKind kind,
                                    char *fmt, ...);

#define MD_PrintGenNoteCComment(f) fprintf((f), "// generated by %s:%d\n", __FILE__, __LINE__)
#endif

//~ Tree Comparison/Verification

MD_FUNCTION MD_b32 MD_NodeMatch(MD_Node *a, MD_Node *b, MD_MatchFlags flags);
MD_FUNCTION MD_b32 MD_NodeDeepMatch(MD_Node *a, MD_Node *b, MD_MatchFlags flags);

//~ Expression Parsing

MD_FUNCTION void               MD_ExprOprPush(MD_Arena *arena, MD_ExprOprList *list,
                                              MD_ExprOprKind kind, MD_u32 precedence,
                                              MD_String8 op_string,
                                              MD_u32 op_id, void *op_ptr);

MD_FUNCTION MD_ExprOprTable    MD_ExprBakeOprTableFromList(MD_Arena *arena,
                                                           MD_ExprOprList *list);
MD_FUNCTION MD_ExprOpr*        MD_ExprOprFromKindString(MD_ExprOprTable *table,
                                                        MD_ExprOprKind kind, MD_String8 s);

MD_FUNCTION MD_ExprParseResult MD_ExprParse(MD_Arena *arena, MD_ExprOprTable *op_table,
                                            MD_Node *first, MD_Node *one_past_last);

MD_FUNCTION MD_Expr* MD_Expr_NewLeaf(MD_Arena *arena, MD_Node *node);
MD_FUNCTION MD_Expr* MD_Expr_NewOpr(MD_Arena *arena, MD_ExprOpr *op, MD_Node *op_node,
                                    MD_Expr *left, MD_Expr *right);

MD_FUNCTION MD_ExprParseCtx MD_ExprParse_MakeContext(MD_ExprOprTable *table);

MD_FUNCTION MD_Expr* MD_ExprParse_TopLevel(MD_Arena *arena, MD_ExprParseCtx *ctx,
                                           MD_Node *first, MD_Node *opl);
MD_FUNCTION MD_b32   MD_ExprParse_OprConsume(MD_ExprParseCtx *ctx,
                                             MD_Node **iter, MD_Node *opl,
                                             MD_ExprOprKind kind,
                                             MD_u32 min_precedence,
                                             MD_ExprOpr **op_out);
MD_FUNCTION MD_Expr* MD_ExprParse_Atom(MD_Arena *arena, MD_ExprParseCtx *ctx,
                                       MD_Node **iter, MD_Node *first, MD_Node *opl);
MD_FUNCTION MD_Expr* MD_ExprParse_MinPrecedence(MD_Arena *arena, MD_ExprParseCtx *ctx,
                                                MD_Node **iter, MD_Node *first, MD_Node *opl,
                                                MD_u32 min_precedence);


//~ String Generation

MD_FUNCTION void MD_DebugDumpFromNode(MD_Arena *arena, MD_String8List *out, MD_Node *node,
                                      int indent, MD_String8 indent_string,
                                      MD_GenerateFlags flags);
MD_FUNCTION void MD_ReconstructionFromNode(MD_Arena *arena, MD_String8List *out, MD_Node *node,
                                           int indent, MD_String8 indent_string);

//~ Command Line Argument Helper

MD_FUNCTION MD_String8List MD_StringListFromArgCV(MD_Arena *arena, int argument_count,
                                                  char **arguments);
MD_FUNCTION MD_CmdLine MD_MakeCmdLineFromOptions(MD_Arena *arena, MD_String8List options);
MD_FUNCTION MD_String8List MD_CmdLineValuesFromString(MD_CmdLine cmdln, MD_String8 name);
MD_FUNCTION MD_b32 MD_CmdLineB32FromString(MD_CmdLine cmdln, MD_String8 name);
MD_FUNCTION MD_i64 MD_CmdLineI64FromString(MD_CmdLine cmdln, MD_String8 name);

//~ File System

MD_FUNCTION MD_String8  MD_LoadEntireFile(MD_Arena *arena, MD_String8 filename);
MD_FUNCTION MD_b32      MD_FileIterBegin(MD_FileIter *it, MD_String8 path);
MD_FUNCTION MD_FileInfo MD_FileIterNext(MD_Arena *arena, MD_FileIter *it);
MD_FUNCTION void        MD_FileIterEnd(MD_FileIter *it);

#endif // MD_H

/*
Copyright 2021 Dion Systems LLC

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.
*/