mirror of
https://github.com/lua/lua
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134 lines
4.3 KiB
C
134 lines
4.3 KiB
C
/*
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** $Id: lparser.h,v 1.75 2015/12/17 15:44:50 roberto Exp roberto $
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** Lua Parser
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** See Copyright Notice in lua.h
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*/
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#ifndef lparser_h
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#define lparser_h
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#include "llimits.h"
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#include "lobject.h"
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#include "lzio.h"
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/*
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** Expression and variable descriptor.
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** Code generation for variables and expressions can be delayed to allow
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** optimizations; An 'expdesc' structure describes a potentially-delayed
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** variable/expression. It has a description of its "main" value plus a
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** list of conditional jumps that can also produce its value (generated
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** by short-circuit operators 'and'/'or').
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*/
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/* kinds of variables/expressions */
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typedef enum {
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VVOID, /* when 'expdesc' describes the last expression a list,
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this kind means an empty list (so, no expression) */
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VNIL, /* constant nil */
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VTRUE, /* constant true */
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VFALSE, /* constant false */
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VK, /* constant in 'k'; info = index of constant in 'k' */
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VKFLT, /* floating constant; nval = numerical float value */
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VKINT, /* integer constant; nval = numerical integer value */
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VNONRELOC, /* expression has its value in a fixed register;
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info = result register */
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VLOCAL, /* local variable; info = local register */
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VUPVAL, /* upvalue variable; info = index of upvalue in 'upvalues' */
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VINDEXED, /* indexed variable;
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ind.vt = whether 't' is register or upvalue;
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ind.t = table register or upvalue;
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ind.idx = key's R/K index */
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VJMP, /* expression is a test/comparison;
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info = pc of corresponding jump instruction */
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VRELOCABLE, /* expression can put result in any register;
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info = instruction pc */
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VCALL, /* expression is a function call; info = instruction pc */
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VVARARG /* vararg expression; info = instruction pc */
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} expkind;
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#define vkisvar(k) (VLOCAL <= (k) && (k) <= VINDEXED)
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#define vkisinreg(k) ((k) == VNONRELOC || (k) == VLOCAL)
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typedef struct expdesc {
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expkind k;
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union {
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lua_Integer ival; /* for VKINT */
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lua_Number nval; /* for VKFLT */
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int info; /* for generic use */
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struct { /* for indexed variables (VINDEXED) */
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short idx; /* index (R/K) */
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lu_byte t; /* table (register or upvalue) */
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lu_byte vt; /* whether 't' is register (VLOCAL) or upvalue (VUPVAL) */
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} ind;
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} u;
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int t; /* patch list of 'exit when true' */
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int f; /* patch list of 'exit when false' */
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} expdesc;
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/* description of active local variable */
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typedef struct Vardesc {
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short idx; /* variable index in stack */
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} Vardesc;
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/* description of pending goto statements and label statements */
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typedef struct Labeldesc {
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TString *name; /* label identifier */
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int pc; /* position in code */
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int line; /* line where it appeared */
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lu_byte nactvar; /* local level where it appears in current block */
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} Labeldesc;
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/* list of labels or gotos */
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typedef struct Labellist {
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Labeldesc *arr; /* array */
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int n; /* number of entries in use */
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int size; /* array size */
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} Labellist;
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/* dynamic structures used by the parser */
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typedef struct Dyndata {
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struct { /* list of active local variables */
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Vardesc *arr;
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int n;
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int size;
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} actvar;
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Labellist gt; /* list of pending gotos */
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Labellist label; /* list of active labels */
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} Dyndata;
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/* control of blocks */
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struct BlockCnt; /* defined in lparser.c */
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/* state needed to generate code for a given function */
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typedef struct FuncState {
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Proto *f; /* current function header */
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struct FuncState *prev; /* enclosing function */
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struct LexState *ls; /* lexical state */
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struct BlockCnt *bl; /* chain of current blocks */
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int pc; /* next position to code (equivalent to 'ncode') */
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int lasttarget; /* 'label' of last 'jump label' */
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int jpc; /* list of pending jumps to 'pc' */
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int nk; /* number of elements in 'k' */
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int np; /* number of elements in 'p' */
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int firstlocal; /* index of first local var (in Dyndata array) */
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short nlocvars; /* number of elements in 'f->locvars' */
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lu_byte nactvar; /* number of active local variables */
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lu_byte nups; /* number of upvalues */
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lu_byte freereg; /* first free register */
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} FuncState;
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LUAI_FUNC LClosure *luaY_parser (lua_State *L, ZIO *z, Mbuffer *buff,
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Dyndata *dyd, const char *name, int firstchar);
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#endif
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