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- /*
- ** $Id: lparser.h $
- ** Lua Parser
- ** See Copyright Notice in lua.h
- */
- #ifndef lparser_h
- #define lparser_h
- #include "llimits.h"
- #include "lobject.h"
- #include "lzio.h"
- /*
- ** Expression and variable descriptor.
- ** Code generation for variables and expressions can be delayed to allow
- ** optimizations; An 'expdesc' structure describes a potentially-delayed
- ** variable/expression. It has a description of its "main" value plus a
- ** list of conditional jumps that can also produce its value (generated
- ** by short-circuit operators 'and'/'or').
- */
- /* kinds of variables/expressions */
- typedef enum {
- VVOID, /* when 'expdesc' describes the last expression of a list,
- this kind means an empty list (so, no expression) */
- VNIL, /* constant nil */
- VTRUE, /* constant true */
- VFALSE, /* constant false */
- VK, /* constant in 'k'; info = index of constant in 'k' */
- VKFLT, /* floating constant; nval = numerical float value */
- VKINT, /* integer constant; ival = numerical integer value */
- VKSTR, /* string constant; strval = TString address;
- (string is fixed by the lexer) */
- VNONRELOC, /* expression has its value in a fixed register;
- info = result register */
- VLOCAL, /* local variable; var.sidx = stack index (local register);
- var.vidx = relative index in 'actvar.arr' */
- VUPVAL, /* upvalue variable; info = index of upvalue in 'upvalues' */
- VCONST, /* compile-time <const> variable;
- info = absolute index in 'actvar.arr' */
- VINDEXED, /* indexed variable;
- ind.t = table register;
- ind.idx = key's R index */
- VINDEXUP, /* indexed upvalue;
- ind.t = table upvalue;
- ind.idx = key's K index */
- VINDEXI, /* indexed variable with constant integer;
- ind.t = table register;
- ind.idx = key's value */
- VINDEXSTR, /* indexed variable with literal string;
- ind.t = table register;
- ind.idx = key's K index */
- VJMP, /* expression is a test/comparison;
- info = pc of corresponding jump instruction */
- VRELOC, /* expression can put result in any register;
- info = instruction pc */
- VCALL, /* expression is a function call; info = instruction pc */
- VVARARG /* vararg expression; info = instruction pc */
- } expkind;
- #define vkisvar(k) (VLOCAL <= (k) && (k) <= VINDEXSTR)
- #define vkisindexed(k) (VINDEXED <= (k) && (k) <= VINDEXSTR)
- typedef struct expdesc {
- expkind k;
- union {
- lua_Integer ival; /* for VKINT */
- lua_Number nval; /* for VKFLT */
- TString *strval; /* for VKSTR */
- int info; /* for generic use */
- struct { /* for indexed variables */
- short idx; /* index (R or "long" K) */
- lu_byte t; /* table (register or upvalue) */
- } ind;
- struct { /* for local variables */
- lu_byte sidx; /* index in the stack */
- unsigned short vidx; /* compiler index (in 'actvar.arr') */
- } var;
- } u;
- int t; /* patch list of 'exit when true' */
- int f; /* patch list of 'exit when false' */
- } expdesc;
- /* kinds of variables */
- #define VDKREG 0 /* regular */
- #define RDKCONST 1 /* constant */
- #define RDKTOCLOSE 2 /* to-be-closed */
- #define RDKCTC 3 /* compile-time constant */
- /* description of an active local variable */
- typedef union Vardesc {
- struct {
- TValuefields; /* constant value (if it is a compile-time constant) */
- lu_byte kind;
- lu_byte sidx; /* index of the variable in the stack */
- short pidx; /* index of the variable in the Proto's 'locvars' array */
- TString *name; /* variable name */
- } vd;
- TValue k; /* constant value (if any) */
- } Vardesc;
- /* description of pending goto statements and label statements */
- typedef struct Labeldesc {
- TString *name; /* label identifier */
- int pc; /* position in code */
- int line; /* line where it appeared */
- lu_byte nactvar; /* number of active variables in that position */
- lu_byte close; /* goto that escapes upvalues */
- } Labeldesc;
- /* list of labels or gotos */
- typedef struct Labellist {
- Labeldesc *arr; /* array */
- int n; /* number of entries in use */
- int size; /* array size */
- } Labellist;
- /* dynamic structures used by the parser */
- typedef struct Dyndata {
- struct { /* list of all active local variables */
- Vardesc *arr;
- int n;
- int size;
- } actvar;
- Labellist gt; /* list of pending gotos */
- Labellist label; /* list of active labels */
- } Dyndata;
- /* control of blocks */
- struct BlockCnt; /* defined in lparser.c */
- /* state needed to generate code for a given function */
- typedef struct FuncState {
- Proto *f; /* current function header */
- struct FuncState *prev; /* enclosing function */
- struct LexState *ls; /* lexical state */
- struct BlockCnt *bl; /* chain of current blocks */
- int pc; /* next position to code (equivalent to 'ncode') */
- int lasttarget; /* 'label' of last 'jump label' */
- int previousline; /* last line that was saved in 'lineinfo' */
- int nk; /* number of elements in 'k' */
- int np; /* number of elements in 'p' */
- int nabslineinfo; /* number of elements in 'abslineinfo' */
- int firstlocal; /* index of first local var (in Dyndata array) */
- int firstlabel; /* index of first label (in 'dyd->label->arr') */
- short ndebugvars; /* number of elements in 'f->locvars' */
- lu_byte nactvar; /* number of active local variables */
- lu_byte nups; /* number of upvalues */
- lu_byte freereg; /* first free register */
- lu_byte iwthabs; /* instructions issued since last absolute line info */
- lu_byte needclose; /* function needs to close upvalues when returning */
- } FuncState;
- LUAI_FUNC int luaY_nvarstack (FuncState *fs);
- LUAI_FUNC LClosure *luaY_parser (lua_State *L, ZIO *z, Mbuffer *buff,
- Dyndata *dyd, const char *name, int firstchar);
- #endif
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