171 lines
5.8 KiB
C
171 lines
5.8 KiB
C
/*
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** $Id: lparser.h $
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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 of 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; ival = numerical integer value */
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VKSTR, /* string constant; strval = TString address;
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(string is fixed by the lexer) */
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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; var.ridx = register index;
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var.vidx = relative index in 'actvar.arr' */
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VUPVAL, /* upvalue variable; info = index of upvalue in 'upvalues' */
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VCONST, /* compile-time <const> variable;
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info = absolute index in 'actvar.arr' */
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VINDEXED, /* indexed variable;
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ind.t = table register;
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ind.idx = key's R index */
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VINDEXUP, /* indexed upvalue;
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ind.t = table upvalue;
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ind.idx = key's K index */
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VINDEXI, /* indexed variable with constant integer;
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ind.t = table register;
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ind.idx = key's value */
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VINDEXSTR, /* indexed variable with literal string;
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ind.t = table register;
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ind.idx = key's 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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VRELOC, /* 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) <= VINDEXSTR)
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#define vkisindexed(k) (VINDEXED <= (k) && (k) <= VINDEXSTR)
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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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TString *strval; /* for VKSTR */
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int info; /* for generic use */
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struct { /* for indexed variables */
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short idx; /* index (R or "long" K) */
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lu_byte t; /* table (register or upvalue) */
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} ind;
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struct { /* for local variables */
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lu_byte ridx; /* register holding the variable */
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unsigned short vidx; /* compiler index (in 'actvar.arr') */
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} var;
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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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/* kinds of variables */
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#define VDKREG 0 /* regular */
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#define RDKCONST 1 /* constant */
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#define RDKTOCLOSE 2 /* to-be-closed */
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#define RDKCTC 3 /* compile-time constant */
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/* description of an active local variable */
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typedef union Vardesc {
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struct {
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TValuefields; /* constant value (if it is a compile-time constant) */
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lu_byte kind;
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lu_byte ridx; /* register holding the variable */
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short pidx; /* index of the variable in the Proto's 'locvars' array */
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TString *name; /* variable name */
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} vd;
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TValue k; /* constant value (if any) */
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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; /* number of active variables in that position */
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lu_byte close; /* goto that escapes upvalues */
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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 all 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 previousline; /* last line that was saved in 'lineinfo' */
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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 nabslineinfo; /* number of elements in 'abslineinfo' */
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int firstlocal; /* index of first local var (in Dyndata array) */
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int firstlabel; /* index of first label (in 'dyd->label->arr') */
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short ndebugvars; /* 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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lu_byte iwthabs; /* instructions issued since last absolute line info */
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lu_byte needclose; /* function needs to close upvalues when returning */
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} FuncState;
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LUAI_FUNC int luaY_nvarstack (FuncState *fs);
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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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