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4cd1f4aac0
Start of the implementation of "scoped variables" or "to be closed" variables, local variables whose '__close' (or themselves) are called when they go out of scope. This commit implements the syntax, the opcode, and the creation of the corresponding upvalue, but it still does not call the finalizations when the variable goes out of scope (the most important part). Currently, the syntax is 'local scoped name = exp', but that will probably change.
145 lines
4.7 KiB
C
145 lines
4.7 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 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.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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#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 */
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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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} 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 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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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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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 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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