ref: 7c452f09cf633586b26565139943844c682e2177
dir: /lptree.h/
/*
** $Id: lptree.h $
*/
#if !defined(lptree_h)
#define lptree_h
#include "lptypes.h"
/*
** types of trees
*/
typedef enum TTag {
TChar = 0, /* 'n' = char */
TSet, /* the set is stored in next CHARSETSIZE bytes */
TAny,
TTrue,
TFalse,
TRep, /* 'sib1'* */
TSeq, /* 'sib1' 'sib2' */
TChoice, /* 'sib1' / 'sib2' */
TNot, /* !'sib1' */
TAnd, /* &'sib1' */
TCall, /* ktable[key] is rule's key; 'sib2' is rule being called */
TOpenCall, /* ktable[key] is rule's key */
TRule, /* ktable[key] is rule's key (but key == 0 for unused rules);
'sib1' is rule's pattern;
'sib2' is next rule; 'cap' is rule's sequential number */
TGrammar, /* 'sib1' is initial (and first) rule */
TBehind, /* 'sib1' is pattern, 'n' is how much to go back */
TCapture, /* captures: 'cap' is kind of capture (enum 'CapKind');
ktable[key] is Lua value associated with capture;
'sib1' is capture body */
TRunTime /* run-time capture: 'key' is Lua function;
'sib1' is capture body */
} TTag;
/*
** Tree trees
** The first child of a tree (if there is one) is immediately after
** the tree. A reference to a second child (ps) is its position
** relative to the position of the tree itself.
*/
typedef struct TTree {
byte tag;
byte cap; /* kind of capture (if it is a capture) */
unsigned short key; /* key in ktable for Lua data (0 if no key) */
union {
int ps; /* occasional second child */
int n; /* occasional counter */
} u;
} TTree;
/*
** A complete pattern has its tree plus, if already compiled,
** its corresponding code
*/
typedef struct Pattern {
union Instruction *code;
int codesize;
TTree tree[1];
} Pattern;
/* number of children for each tree */
extern const byte numsiblings[];
/* access to children */
#define sib1(t) ((t) + 1)
#define sib2(t) ((t) + (t)->u.ps)
#endif