[1803] | 1 | /* |
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| 2 | ** $Id: lparser.c,v 1.208a 2003/04/03 13:35:34 roberto Exp $ |
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| 3 | ** Lua Parser |
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| 4 | ** See Copyright Notice in lua.h |
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| 5 | */ |
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| 6 | |
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| 7 | |
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| 8 | #include <string.h> |
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| 9 | |
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| 10 | #define lparser_c |
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| 11 | |
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| 12 | #include "lua.h" |
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| 13 | |
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| 14 | #include "lcode.h" |
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| 15 | #include "ldebug.h" |
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| 16 | #include "lfunc.h" |
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| 17 | #include "llex.h" |
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| 18 | #include "lmem.h" |
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| 19 | #include "lobject.h" |
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| 20 | #include "lopcodes.h" |
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| 21 | #include "lparser.h" |
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| 22 | #include "lstate.h" |
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| 23 | #include "lstring.h" |
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| 24 | |
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| 25 | |
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| 26 | |
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| 27 | |
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| 28 | #define getlocvar(fs, i) ((fs)->f->locvars[(fs)->actvar[i]]) |
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| 29 | |
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| 30 | |
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| 31 | #define enterlevel(ls) if (++(ls)->nestlevel > LUA_MAXPARSERLEVEL) \ |
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| 32 | luaX_syntaxerror(ls, "too many syntax levels"); |
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| 33 | #define leavelevel(ls) ((ls)->nestlevel--) |
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| 34 | |
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| 35 | |
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| 36 | /* |
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| 37 | ** nodes for block list (list of active blocks) |
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| 38 | */ |
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| 39 | typedef struct BlockCnt { |
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| 40 | struct BlockCnt *previous; /* chain */ |
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| 41 | int breaklist; /* list of jumps out of this loop */ |
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| 42 | int nactvar; /* # active local variables outside the breakable structure */ |
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| 43 | int upval; /* true if some variable in the block is an upvalue */ |
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| 44 | int isbreakable; /* true if `block' is a loop */ |
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| 45 | } BlockCnt; |
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| 46 | |
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| 47 | |
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| 48 | |
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| 49 | /* |
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| 50 | ** prototypes for recursive non-terminal functions |
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| 51 | */ |
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| 52 | static void chunk (LexState *ls); |
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| 53 | static void expr (LexState *ls, expdesc *v); |
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| 54 | |
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| 55 | |
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| 56 | |
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| 57 | static void next (LexState *ls) { |
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| 58 | ls->lastline = ls->linenumber; |
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| 59 | if (ls->lookahead.token != TK_EOS) { /* is there a look-ahead token? */ |
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| 60 | ls->t = ls->lookahead; /* use this one */ |
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| 61 | ls->lookahead.token = TK_EOS; /* and discharge it */ |
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| 62 | } |
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| 63 | else |
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| 64 | ls->t.token = luaX_lex(ls, &ls->t.seminfo); /* read next token */ |
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| 65 | } |
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| 66 | |
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| 67 | |
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| 68 | static void lookahead (LexState *ls) { |
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| 69 | lua_assert(ls->lookahead.token == TK_EOS); |
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| 70 | ls->lookahead.token = luaX_lex(ls, &ls->lookahead.seminfo); |
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| 71 | } |
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| 72 | |
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| 73 | |
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| 74 | static void error_expected (LexState *ls, int token) { |
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| 75 | luaX_syntaxerror(ls, |
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| 76 | luaO_pushfstring(ls->L, "`%s' expected", luaX_token2str(ls, token))); |
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| 77 | } |
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| 78 | |
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| 79 | |
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| 80 | static int testnext (LexState *ls, int c) { |
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| 81 | if (ls->t.token == c) { |
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| 82 | next(ls); |
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| 83 | return 1; |
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| 84 | } |
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| 85 | else return 0; |
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| 86 | } |
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| 87 | |
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| 88 | |
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| 89 | static void check (LexState *ls, int c) { |
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| 90 | if (!testnext(ls, c)) |
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| 91 | error_expected(ls, c); |
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| 92 | } |
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| 93 | |
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| 94 | |
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| 95 | #define check_condition(ls,c,msg) { if (!(c)) luaX_syntaxerror(ls, msg); } |
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| 96 | |
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| 97 | |
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| 98 | |
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| 99 | static void check_match (LexState *ls, int what, int who, int where) { |
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| 100 | if (!testnext(ls, what)) { |
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| 101 | if (where == ls->linenumber) |
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| 102 | error_expected(ls, what); |
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| 103 | else { |
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| 104 | luaX_syntaxerror(ls, luaO_pushfstring(ls->L, |
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| 105 | "`%s' expected (to close `%s' at line %d)", |
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| 106 | luaX_token2str(ls, what), luaX_token2str(ls, who), where)); |
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| 107 | } |
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| 108 | } |
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| 109 | } |
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| 110 | |
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| 111 | |
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| 112 | static TString *str_checkname (LexState *ls) { |
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| 113 | TString *ts; |
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| 114 | check_condition(ls, (ls->t.token == TK_NAME), "<name> expected"); |
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| 115 | ts = ls->t.seminfo.ts; |
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| 116 | next(ls); |
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| 117 | return ts; |
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| 118 | } |
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| 119 | |
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| 120 | |
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| 121 | static void init_exp (expdesc *e, expkind k, int i) { |
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| 122 | e->f = e->t = NO_JUMP; |
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| 123 | e->k = k; |
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| 124 | e->info = i; |
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| 125 | } |
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| 126 | |
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| 127 | |
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| 128 | static void codestring (LexState *ls, expdesc *e, TString *s) { |
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| 129 | init_exp(e, VK, luaK_stringK(ls->fs, s)); |
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| 130 | } |
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| 131 | |
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| 132 | |
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| 133 | static void checkname(LexState *ls, expdesc *e) { |
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| 134 | codestring(ls, e, str_checkname(ls)); |
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| 135 | } |
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| 136 | |
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| 137 | |
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| 138 | static int luaI_registerlocalvar (LexState *ls, TString *varname) { |
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| 139 | FuncState *fs = ls->fs; |
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| 140 | Proto *f = fs->f; |
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| 141 | luaM_growvector(ls->L, f->locvars, fs->nlocvars, f->sizelocvars, |
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| 142 | LocVar, MAX_INT, ""); |
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| 143 | f->locvars[fs->nlocvars].varname = varname; |
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| 144 | return fs->nlocvars++; |
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| 145 | } |
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| 146 | |
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| 147 | |
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| 148 | static void new_localvar (LexState *ls, TString *name, int n) { |
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| 149 | FuncState *fs = ls->fs; |
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| 150 | luaX_checklimit(ls, fs->nactvar+n+1, MAXVARS, "local variables"); |
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| 151 | fs->actvar[fs->nactvar+n] = luaI_registerlocalvar(ls, name); |
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| 152 | } |
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| 153 | |
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| 154 | |
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| 155 | static void adjustlocalvars (LexState *ls, int nvars) { |
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| 156 | FuncState *fs = ls->fs; |
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| 157 | fs->nactvar += nvars; |
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| 158 | for (; nvars; nvars--) { |
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| 159 | getlocvar(fs, fs->nactvar - nvars).startpc = fs->pc; |
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| 160 | } |
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| 161 | } |
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| 162 | |
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| 163 | |
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| 164 | static void removevars (LexState *ls, int tolevel) { |
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| 165 | FuncState *fs = ls->fs; |
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| 166 | while (fs->nactvar > tolevel) |
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| 167 | getlocvar(fs, --fs->nactvar).endpc = fs->pc; |
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| 168 | } |
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| 169 | |
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| 170 | |
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| 171 | static void new_localvarstr (LexState *ls, const char *name, int n) { |
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| 172 | new_localvar(ls, luaS_new(ls->L, name), n); |
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| 173 | } |
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| 174 | |
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| 175 | |
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| 176 | static void create_local (LexState *ls, const char *name) { |
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| 177 | new_localvarstr(ls, name, 0); |
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| 178 | adjustlocalvars(ls, 1); |
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| 179 | } |
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| 180 | |
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| 181 | |
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| 182 | static int indexupvalue (FuncState *fs, TString *name, expdesc *v) { |
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| 183 | int i; |
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| 184 | Proto *f = fs->f; |
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| 185 | for (i=0; i<f->nups; i++) { |
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| 186 | if (fs->upvalues[i].k == v->k && fs->upvalues[i].info == v->info) { |
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| 187 | lua_assert(fs->f->upvalues[i] == name); |
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| 188 | return i; |
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| 189 | } |
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| 190 | } |
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| 191 | /* new one */ |
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| 192 | luaX_checklimit(fs->ls, f->nups + 1, MAXUPVALUES, "upvalues"); |
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| 193 | luaM_growvector(fs->L, fs->f->upvalues, f->nups, fs->f->sizeupvalues, |
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| 194 | TString *, MAX_INT, ""); |
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| 195 | fs->f->upvalues[f->nups] = name; |
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| 196 | fs->upvalues[f->nups] = *v; |
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| 197 | return f->nups++; |
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| 198 | } |
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| 199 | |
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| 200 | |
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| 201 | static int searchvar (FuncState *fs, TString *n) { |
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| 202 | int i; |
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| 203 | for (i=fs->nactvar-1; i >= 0; i--) { |
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| 204 | if (n == getlocvar(fs, i).varname) |
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| 205 | return i; |
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| 206 | } |
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| 207 | return -1; /* not found */ |
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| 208 | } |
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| 209 | |
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| 210 | |
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| 211 | static void markupval (FuncState *fs, int level) { |
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| 212 | BlockCnt *bl = fs->bl; |
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| 213 | while (bl && bl->nactvar > level) bl = bl->previous; |
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| 214 | if (bl) bl->upval = 1; |
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| 215 | } |
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| 216 | |
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| 217 | |
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| 218 | static void singlevaraux (FuncState *fs, TString *n, expdesc *var, int base) { |
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| 219 | if (fs == NULL) /* no more levels? */ |
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| 220 | init_exp(var, VGLOBAL, NO_REG); /* default is global variable */ |
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| 221 | else { |
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| 222 | int v = searchvar(fs, n); /* look up at current level */ |
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| 223 | if (v >= 0) { |
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| 224 | init_exp(var, VLOCAL, v); |
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| 225 | if (!base) |
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| 226 | markupval(fs, v); /* local will be used as an upval */ |
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| 227 | } |
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| 228 | else { /* not found at current level; try upper one */ |
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| 229 | singlevaraux(fs->prev, n, var, 0); |
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| 230 | if (var->k == VGLOBAL) { |
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| 231 | if (base) |
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| 232 | var->info = luaK_stringK(fs, n); /* info points to global name */ |
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| 233 | } |
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| 234 | else { /* LOCAL or UPVAL */ |
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| 235 | var->info = indexupvalue(fs, n, var); |
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| 236 | var->k = VUPVAL; /* upvalue in this level */ |
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| 237 | } |
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| 238 | } |
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| 239 | } |
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| 240 | } |
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| 241 | |
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| 242 | |
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| 243 | static TString *singlevar (LexState *ls, expdesc *var, int base) { |
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| 244 | TString *varname = str_checkname(ls); |
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| 245 | singlevaraux(ls->fs, varname, var, base); |
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| 246 | return varname; |
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| 247 | } |
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| 248 | |
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| 249 | |
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| 250 | static void adjust_assign (LexState *ls, int nvars, int nexps, expdesc *e) { |
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| 251 | FuncState *fs = ls->fs; |
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| 252 | int extra = nvars - nexps; |
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| 253 | if (e->k == VCALL) { |
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| 254 | extra++; /* includes call itself */ |
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| 255 | if (extra <= 0) extra = 0; |
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| 256 | else luaK_reserveregs(fs, extra-1); |
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| 257 | luaK_setcallreturns(fs, e, extra); /* call provides the difference */ |
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| 258 | } |
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| 259 | else { |
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| 260 | if (e->k != VVOID) luaK_exp2nextreg(fs, e); /* close last expression */ |
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| 261 | if (extra > 0) { |
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| 262 | int reg = fs->freereg; |
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| 263 | luaK_reserveregs(fs, extra); |
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| 264 | luaK_nil(fs, reg, extra); |
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| 265 | } |
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| 266 | } |
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| 267 | } |
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| 268 | |
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| 269 | |
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| 270 | static void code_params (LexState *ls, int nparams, int dots) { |
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| 271 | FuncState *fs = ls->fs; |
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| 272 | adjustlocalvars(ls, nparams); |
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| 273 | luaX_checklimit(ls, fs->nactvar, MAXPARAMS, "parameters"); |
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| 274 | fs->f->numparams = cast(lu_byte, fs->nactvar); |
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| 275 | fs->f->is_vararg = cast(lu_byte, dots); |
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| 276 | if (dots) |
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| 277 | create_local(ls, "arg"); |
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| 278 | luaK_reserveregs(fs, fs->nactvar); /* reserve register for parameters */ |
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| 279 | } |
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| 280 | |
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| 281 | |
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| 282 | static void enterblock (FuncState *fs, BlockCnt *bl, int isbreakable) { |
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| 283 | bl->breaklist = NO_JUMP; |
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| 284 | bl->isbreakable = isbreakable; |
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| 285 | bl->nactvar = fs->nactvar; |
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| 286 | bl->upval = 0; |
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| 287 | bl->previous = fs->bl; |
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| 288 | fs->bl = bl; |
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| 289 | lua_assert(fs->freereg == fs->nactvar); |
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| 290 | } |
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| 291 | |
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| 292 | |
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| 293 | static void leaveblock (FuncState *fs) { |
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| 294 | BlockCnt *bl = fs->bl; |
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| 295 | fs->bl = bl->previous; |
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| 296 | removevars(fs->ls, bl->nactvar); |
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| 297 | if (bl->upval) |
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| 298 | luaK_codeABC(fs, OP_CLOSE, bl->nactvar, 0, 0); |
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| 299 | lua_assert(bl->nactvar == fs->nactvar); |
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| 300 | fs->freereg = fs->nactvar; /* free registers */ |
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| 301 | luaK_patchtohere(fs, bl->breaklist); |
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| 302 | } |
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| 303 | |
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| 304 | |
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| 305 | static void pushclosure (LexState *ls, FuncState *func, expdesc *v) { |
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| 306 | FuncState *fs = ls->fs; |
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| 307 | Proto *f = fs->f; |
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| 308 | int i; |
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| 309 | luaM_growvector(ls->L, f->p, fs->np, f->sizep, Proto *, |
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| 310 | MAXARG_Bx, "constant table overflow"); |
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| 311 | f->p[fs->np++] = func->f; |
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| 312 | init_exp(v, VRELOCABLE, luaK_codeABx(fs, OP_CLOSURE, 0, fs->np-1)); |
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| 313 | for (i=0; i<func->f->nups; i++) { |
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| 314 | OpCode o = (func->upvalues[i].k == VLOCAL) ? OP_MOVE : OP_GETUPVAL; |
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| 315 | luaK_codeABC(fs, o, 0, func->upvalues[i].info, 0); |
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| 316 | } |
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| 317 | } |
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| 318 | |
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| 319 | |
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| 320 | static void open_func (LexState *ls, FuncState *fs) { |
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| 321 | Proto *f = luaF_newproto(ls->L); |
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| 322 | fs->f = f; |
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| 323 | fs->prev = ls->fs; /* linked list of funcstates */ |
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| 324 | fs->ls = ls; |
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| 325 | fs->L = ls->L; |
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| 326 | ls->fs = fs; |
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| 327 | fs->pc = 0; |
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| 328 | fs->lasttarget = 0; |
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| 329 | fs->jpc = NO_JUMP; |
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| 330 | fs->freereg = 0; |
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| 331 | fs->nk = 0; |
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| 332 | fs->h = luaH_new(ls->L, 0, 0); |
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| 333 | fs->np = 0; |
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| 334 | fs->nlocvars = 0; |
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| 335 | fs->nactvar = 0; |
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| 336 | fs->bl = NULL; |
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| 337 | f->source = ls->source; |
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| 338 | f->maxstacksize = 2; /* registers 0/1 are always valid */ |
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| 339 | } |
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| 340 | |
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| 341 | |
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| 342 | static void close_func (LexState *ls) { |
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| 343 | lua_State *L = ls->L; |
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| 344 | FuncState *fs = ls->fs; |
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| 345 | Proto *f = fs->f; |
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| 346 | removevars(ls, 0); |
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| 347 | luaK_codeABC(fs, OP_RETURN, 0, 1, 0); /* final return */ |
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| 348 | luaM_reallocvector(L, f->code, f->sizecode, fs->pc, Instruction); |
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| 349 | f->sizecode = fs->pc; |
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| 350 | luaM_reallocvector(L, f->lineinfo, f->sizelineinfo, fs->pc, int); |
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| 351 | f->sizelineinfo = fs->pc; |
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| 352 | luaM_reallocvector(L, f->k, f->sizek, fs->nk, TObject); |
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| 353 | f->sizek = fs->nk; |
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| 354 | luaM_reallocvector(L, f->p, f->sizep, fs->np, Proto *); |
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| 355 | f->sizep = fs->np; |
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| 356 | luaM_reallocvector(L, f->locvars, f->sizelocvars, fs->nlocvars, LocVar); |
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| 357 | f->sizelocvars = fs->nlocvars; |
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| 358 | luaM_reallocvector(L, f->upvalues, f->sizeupvalues, f->nups, TString *); |
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| 359 | f->sizeupvalues = f->nups; |
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| 360 | lua_assert(luaG_checkcode(f)); |
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| 361 | lua_assert(fs->bl == NULL); |
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| 362 | ls->fs = fs->prev; |
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| 363 | } |
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| 364 | |
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| 365 | |
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| 366 | Proto *luaY_parser (lua_State *L, ZIO *z, Mbuffer *buff) { |
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| 367 | struct LexState lexstate; |
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| 368 | struct FuncState funcstate; |
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| 369 | lexstate.buff = buff; |
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| 370 | lexstate.nestlevel = 0; |
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| 371 | luaX_setinput(L, &lexstate, z, luaS_new(L, zname(z))); |
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| 372 | open_func(&lexstate, &funcstate); |
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| 373 | next(&lexstate); /* read first token */ |
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| 374 | chunk(&lexstate); |
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| 375 | check_condition(&lexstate, (lexstate.t.token == TK_EOS), "<eof> expected"); |
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| 376 | close_func(&lexstate); |
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| 377 | lua_assert(funcstate.prev == NULL); |
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| 378 | lua_assert(funcstate.f->nups == 0); |
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| 379 | lua_assert(lexstate.nestlevel == 0); |
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| 380 | return funcstate.f; |
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| 381 | } |
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| 382 | |
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| 383 | |
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| 384 | |
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| 385 | /*============================================================*/ |
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| 386 | /* GRAMMAR RULES */ |
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| 387 | /*============================================================*/ |
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| 388 | |
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| 389 | |
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| 390 | static void luaY_field (LexState *ls, expdesc *v) { |
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| 391 | /* field -> ['.' | ':'] NAME */ |
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| 392 | FuncState *fs = ls->fs; |
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| 393 | expdesc key; |
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| 394 | luaK_exp2anyreg(fs, v); |
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| 395 | next(ls); /* skip the dot or colon */ |
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| 396 | checkname(ls, &key); |
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| 397 | luaK_indexed(fs, v, &key); |
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| 398 | } |
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| 399 | |
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| 400 | |
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| 401 | static void luaY_index (LexState *ls, expdesc *v) { |
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| 402 | /* index -> '[' expr ']' */ |
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| 403 | next(ls); /* skip the '[' */ |
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| 404 | expr(ls, v); |
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| 405 | luaK_exp2val(ls->fs, v); |
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| 406 | check(ls, ']'); |
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| 407 | } |
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| 408 | |
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| 409 | |
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| 410 | /* |
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| 411 | ** {====================================================================== |
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| 412 | ** Rules for Constructors |
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| 413 | ** ======================================================================= |
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| 414 | */ |
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| 415 | |
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| 416 | |
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| 417 | struct ConsControl { |
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| 418 | expdesc v; /* last list item read */ |
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| 419 | expdesc *t; /* table descriptor */ |
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| 420 | int nh; /* total number of `record' elements */ |
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| 421 | int na; /* total number of array elements */ |
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| 422 | int tostore; /* number of array elements pending to be stored */ |
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| 423 | }; |
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| 424 | |
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| 425 | |
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| 426 | static void recfield (LexState *ls, struct ConsControl *cc) { |
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| 427 | /* recfield -> (NAME | `['exp1`]') = exp1 */ |
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| 428 | FuncState *fs = ls->fs; |
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| 429 | int reg = ls->fs->freereg; |
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| 430 | expdesc key, val; |
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| 431 | if (ls->t.token == TK_NAME) { |
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| 432 | luaX_checklimit(ls, cc->nh, MAX_INT, "items in a constructor"); |
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| 433 | cc->nh++; |
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| 434 | checkname(ls, &key); |
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| 435 | } |
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| 436 | else /* ls->t.token == '[' */ |
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| 437 | luaY_index(ls, &key); |
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| 438 | check(ls, '='); |
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| 439 | luaK_exp2RK(fs, &key); |
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| 440 | expr(ls, &val); |
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| 441 | luaK_codeABC(fs, OP_SETTABLE, cc->t->info, luaK_exp2RK(fs, &key), |
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| 442 | luaK_exp2RK(fs, &val)); |
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| 443 | fs->freereg = reg; /* free registers */ |
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| 444 | } |
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| 445 | |
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| 446 | |
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| 447 | static void closelistfield (FuncState *fs, struct ConsControl *cc) { |
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| 448 | if (cc->v.k == VVOID) return; /* there is no list item */ |
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| 449 | luaK_exp2nextreg(fs, &cc->v); |
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| 450 | cc->v.k = VVOID; |
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| 451 | if (cc->tostore == LFIELDS_PER_FLUSH) { |
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| 452 | luaK_codeABx(fs, OP_SETLIST, cc->t->info, cc->na-1); /* flush */ |
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| 453 | cc->tostore = 0; /* no more items pending */ |
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| 454 | fs->freereg = cc->t->info + 1; /* free registers */ |
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| 455 | } |
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| 456 | } |
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| 457 | |
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| 458 | |
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| 459 | static void lastlistfield (FuncState *fs, struct ConsControl *cc) { |
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| 460 | if (cc->tostore == 0) return; |
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| 461 | if (cc->v.k == VCALL) { |
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| 462 | luaK_setcallreturns(fs, &cc->v, LUA_MULTRET); |
---|
| 463 | luaK_codeABx(fs, OP_SETLISTO, cc->t->info, cc->na-1); |
---|
| 464 | } |
---|
| 465 | else { |
---|
| 466 | if (cc->v.k != VVOID) |
---|
| 467 | luaK_exp2nextreg(fs, &cc->v); |
---|
| 468 | luaK_codeABx(fs, OP_SETLIST, cc->t->info, cc->na-1); |
---|
| 469 | } |
---|
| 470 | fs->freereg = cc->t->info + 1; /* free registers */ |
---|
| 471 | } |
---|
| 472 | |
---|
| 473 | |
---|
| 474 | static void listfield (LexState *ls, struct ConsControl *cc) { |
---|
| 475 | expr(ls, &cc->v); |
---|
| 476 | luaX_checklimit(ls, cc->na, MAXARG_Bx, "items in a constructor"); |
---|
| 477 | cc->na++; |
---|
| 478 | cc->tostore++; |
---|
| 479 | } |
---|
| 480 | |
---|
| 481 | |
---|
| 482 | static void constructor (LexState *ls, expdesc *t) { |
---|
| 483 | /* constructor -> ?? */ |
---|
| 484 | FuncState *fs = ls->fs; |
---|
| 485 | int line = ls->linenumber; |
---|
| 486 | int pc = luaK_codeABC(fs, OP_NEWTABLE, 0, 0, 0); |
---|
| 487 | struct ConsControl cc; |
---|
| 488 | cc.na = cc.nh = cc.tostore = 0; |
---|
| 489 | cc.t = t; |
---|
| 490 | init_exp(t, VRELOCABLE, pc); |
---|
| 491 | init_exp(&cc.v, VVOID, 0); /* no value (yet) */ |
---|
| 492 | luaK_exp2nextreg(ls->fs, t); /* fix it at stack top (for gc) */ |
---|
| 493 | check(ls, '{'); |
---|
| 494 | do { |
---|
| 495 | lua_assert(cc.v.k == VVOID || cc.tostore > 0); |
---|
| 496 | testnext(ls, ';'); /* compatibility only */ |
---|
| 497 | if (ls->t.token == '}') break; |
---|
| 498 | closelistfield(fs, &cc); |
---|
| 499 | switch(ls->t.token) { |
---|
| 500 | case TK_NAME: { /* may be listfields or recfields */ |
---|
| 501 | lookahead(ls); |
---|
| 502 | if (ls->lookahead.token != '=') /* expression? */ |
---|
| 503 | listfield(ls, &cc); |
---|
| 504 | else |
---|
| 505 | recfield(ls, &cc); |
---|
| 506 | break; |
---|
| 507 | } |
---|
| 508 | case '[': { /* constructor_item -> recfield */ |
---|
| 509 | recfield(ls, &cc); |
---|
| 510 | break; |
---|
| 511 | } |
---|
| 512 | default: { /* constructor_part -> listfield */ |
---|
| 513 | listfield(ls, &cc); |
---|
| 514 | break; |
---|
| 515 | } |
---|
| 516 | } |
---|
| 517 | } while (testnext(ls, ',') || testnext(ls, ';')); |
---|
| 518 | check_match(ls, '}', '{', line); |
---|
| 519 | lastlistfield(fs, &cc); |
---|
| 520 | SETARG_B(fs->f->code[pc], luaO_int2fb(cc.na)); /* set initial array size */ |
---|
| 521 | SETARG_C(fs->f->code[pc], luaO_log2(cc.nh)+1); /* set initial table size */ |
---|
| 522 | } |
---|
| 523 | |
---|
| 524 | /* }====================================================================== */ |
---|
| 525 | |
---|
| 526 | |
---|
| 527 | |
---|
| 528 | static void parlist (LexState *ls) { |
---|
| 529 | /* parlist -> [ param { `,' param } ] */ |
---|
| 530 | int nparams = 0; |
---|
| 531 | int dots = 0; |
---|
| 532 | if (ls->t.token != ')') { /* is `parlist' not empty? */ |
---|
| 533 | do { |
---|
| 534 | switch (ls->t.token) { |
---|
| 535 | case TK_DOTS: dots = 1; next(ls); break; |
---|
| 536 | case TK_NAME: new_localvar(ls, str_checkname(ls), nparams++); break; |
---|
| 537 | default: luaX_syntaxerror(ls, "<name> or `...' expected"); |
---|
| 538 | } |
---|
| 539 | } while (!dots && testnext(ls, ',')); |
---|
| 540 | } |
---|
| 541 | code_params(ls, nparams, dots); |
---|
| 542 | } |
---|
| 543 | |
---|
| 544 | |
---|
| 545 | static void body (LexState *ls, expdesc *e, int needself, int line) { |
---|
| 546 | /* body -> `(' parlist `)' chunk END */ |
---|
| 547 | FuncState new_fs; |
---|
| 548 | open_func(ls, &new_fs); |
---|
| 549 | new_fs.f->lineDefined = line; |
---|
| 550 | check(ls, '('); |
---|
| 551 | if (needself) |
---|
| 552 | create_local(ls, "self"); |
---|
| 553 | parlist(ls); |
---|
| 554 | check(ls, ')'); |
---|
| 555 | chunk(ls); |
---|
| 556 | check_match(ls, TK_END, TK_FUNCTION, line); |
---|
| 557 | close_func(ls); |
---|
| 558 | pushclosure(ls, &new_fs, e); |
---|
| 559 | } |
---|
| 560 | |
---|
| 561 | |
---|
| 562 | static int explist1 (LexState *ls, expdesc *v) { |
---|
| 563 | /* explist1 -> expr { `,' expr } */ |
---|
| 564 | int n = 1; /* at least one expression */ |
---|
| 565 | expr(ls, v); |
---|
| 566 | while (testnext(ls, ',')) { |
---|
| 567 | luaK_exp2nextreg(ls->fs, v); |
---|
| 568 | expr(ls, v); |
---|
| 569 | n++; |
---|
| 570 | } |
---|
| 571 | return n; |
---|
| 572 | } |
---|
| 573 | |
---|
| 574 | |
---|
| 575 | static void funcargs (LexState *ls, expdesc *f) { |
---|
| 576 | FuncState *fs = ls->fs; |
---|
| 577 | expdesc args; |
---|
| 578 | int base, nparams; |
---|
| 579 | int line = ls->linenumber; |
---|
| 580 | switch (ls->t.token) { |
---|
| 581 | case '(': { /* funcargs -> `(' [ explist1 ] `)' */ |
---|
| 582 | if (line != ls->lastline) |
---|
| 583 | luaX_syntaxerror(ls,"ambiguous syntax (function call x new statement)"); |
---|
| 584 | next(ls); |
---|
| 585 | if (ls->t.token == ')') /* arg list is empty? */ |
---|
| 586 | args.k = VVOID; |
---|
| 587 | else { |
---|
| 588 | explist1(ls, &args); |
---|
| 589 | luaK_setcallreturns(fs, &args, LUA_MULTRET); |
---|
| 590 | } |
---|
| 591 | check_match(ls, ')', '(', line); |
---|
| 592 | break; |
---|
| 593 | } |
---|
| 594 | case '{': { /* funcargs -> constructor */ |
---|
| 595 | constructor(ls, &args); |
---|
| 596 | break; |
---|
| 597 | } |
---|
| 598 | case TK_STRING: { /* funcargs -> STRING */ |
---|
| 599 | codestring(ls, &args, ls->t.seminfo.ts); |
---|
| 600 | next(ls); /* must use `seminfo' before `next' */ |
---|
| 601 | break; |
---|
| 602 | } |
---|
| 603 | default: { |
---|
| 604 | luaX_syntaxerror(ls, "function arguments expected"); |
---|
| 605 | return; |
---|
| 606 | } |
---|
| 607 | } |
---|
| 608 | lua_assert(f->k == VNONRELOC); |
---|
| 609 | base = f->info; /* base register for call */ |
---|
| 610 | if (args.k == VCALL) |
---|
| 611 | nparams = LUA_MULTRET; /* open call */ |
---|
| 612 | else { |
---|
| 613 | if (args.k != VVOID) |
---|
| 614 | luaK_exp2nextreg(fs, &args); /* close last argument */ |
---|
| 615 | nparams = fs->freereg - (base+1); |
---|
| 616 | } |
---|
| 617 | init_exp(f, VCALL, luaK_codeABC(fs, OP_CALL, base, nparams+1, 2)); |
---|
| 618 | luaK_fixline(fs, line); |
---|
| 619 | fs->freereg = base+1; /* call remove function and arguments and leaves |
---|
| 620 | (unless changed) one result */ |
---|
| 621 | } |
---|
| 622 | |
---|
| 623 | |
---|
| 624 | |
---|
| 625 | |
---|
| 626 | /* |
---|
| 627 | ** {====================================================================== |
---|
| 628 | ** Expression parsing |
---|
| 629 | ** ======================================================================= |
---|
| 630 | */ |
---|
| 631 | |
---|
| 632 | |
---|
| 633 | static void prefixexp (LexState *ls, expdesc *v) { |
---|
| 634 | /* prefixexp -> NAME | '(' expr ')' */ |
---|
| 635 | switch (ls->t.token) { |
---|
| 636 | case '(': { |
---|
| 637 | int line = ls->linenumber; |
---|
| 638 | next(ls); |
---|
| 639 | expr(ls, v); |
---|
| 640 | check_match(ls, ')', '(', line); |
---|
| 641 | luaK_dischargevars(ls->fs, v); |
---|
| 642 | return; |
---|
| 643 | } |
---|
| 644 | case TK_NAME: { |
---|
| 645 | singlevar(ls, v, 1); |
---|
| 646 | return; |
---|
| 647 | } |
---|
| 648 | #ifdef LUA_COMPATUPSYNTAX |
---|
| 649 | case '%': { /* for compatibility only */ |
---|
| 650 | TString *varname; |
---|
| 651 | int line = ls->linenumber; |
---|
| 652 | next(ls); /* skip `%' */ |
---|
| 653 | varname = singlevar(ls, v, 1); |
---|
| 654 | if (v->k != VUPVAL) |
---|
| 655 | luaX_errorline(ls, "global upvalues are obsolete", |
---|
| 656 | getstr(varname), line); |
---|
| 657 | return; |
---|
| 658 | } |
---|
| 659 | #endif |
---|
| 660 | default: { |
---|
| 661 | luaX_syntaxerror(ls, "unexpected symbol"); |
---|
| 662 | return; |
---|
| 663 | } |
---|
| 664 | } |
---|
| 665 | } |
---|
| 666 | |
---|
| 667 | |
---|
| 668 | static void primaryexp (LexState *ls, expdesc *v) { |
---|
| 669 | /* primaryexp -> |
---|
| 670 | prefixexp { `.' NAME | `[' exp `]' | `:' NAME funcargs | funcargs } */ |
---|
| 671 | FuncState *fs = ls->fs; |
---|
| 672 | prefixexp(ls, v); |
---|
| 673 | for (;;) { |
---|
| 674 | switch (ls->t.token) { |
---|
| 675 | case '.': { /* field */ |
---|
| 676 | luaY_field(ls, v); |
---|
| 677 | break; |
---|
| 678 | } |
---|
| 679 | case '[': { /* `[' exp1 `]' */ |
---|
| 680 | expdesc key; |
---|
| 681 | luaK_exp2anyreg(fs, v); |
---|
| 682 | luaY_index(ls, &key); |
---|
| 683 | luaK_indexed(fs, v, &key); |
---|
| 684 | break; |
---|
| 685 | } |
---|
| 686 | case ':': { /* `:' NAME funcargs */ |
---|
| 687 | expdesc key; |
---|
| 688 | next(ls); |
---|
| 689 | checkname(ls, &key); |
---|
| 690 | luaK_self(fs, v, &key); |
---|
| 691 | funcargs(ls, v); |
---|
| 692 | break; |
---|
| 693 | } |
---|
| 694 | case '(': case TK_STRING: case '{': { /* funcargs */ |
---|
| 695 | luaK_exp2nextreg(fs, v); |
---|
| 696 | funcargs(ls, v); |
---|
| 697 | break; |
---|
| 698 | } |
---|
| 699 | default: return; |
---|
| 700 | } |
---|
| 701 | } |
---|
| 702 | } |
---|
| 703 | |
---|
| 704 | |
---|
| 705 | static void simpleexp (LexState *ls, expdesc *v) { |
---|
| 706 | /* simpleexp -> NUMBER | STRING | NIL | constructor | FUNCTION body |
---|
| 707 | | primaryexp */ |
---|
| 708 | switch (ls->t.token) { |
---|
| 709 | case TK_NUMBER: { |
---|
| 710 | init_exp(v, VK, luaK_numberK(ls->fs, ls->t.seminfo.r)); |
---|
| 711 | next(ls); /* must use `seminfo' before `next' */ |
---|
| 712 | break; |
---|
| 713 | } |
---|
| 714 | case TK_STRING: { |
---|
| 715 | codestring(ls, v, ls->t.seminfo.ts); |
---|
| 716 | next(ls); /* must use `seminfo' before `next' */ |
---|
| 717 | break; |
---|
| 718 | } |
---|
| 719 | case TK_NIL: { |
---|
| 720 | init_exp(v, VNIL, 0); |
---|
| 721 | next(ls); |
---|
| 722 | break; |
---|
| 723 | } |
---|
| 724 | case TK_TRUE: { |
---|
| 725 | init_exp(v, VTRUE, 0); |
---|
| 726 | next(ls); |
---|
| 727 | break; |
---|
| 728 | } |
---|
| 729 | case TK_FALSE: { |
---|
| 730 | init_exp(v, VFALSE, 0); |
---|
| 731 | next(ls); |
---|
| 732 | break; |
---|
| 733 | } |
---|
| 734 | case '{': { /* constructor */ |
---|
| 735 | constructor(ls, v); |
---|
| 736 | break; |
---|
| 737 | } |
---|
| 738 | case TK_FUNCTION: { |
---|
| 739 | next(ls); |
---|
| 740 | body(ls, v, 0, ls->linenumber); |
---|
| 741 | break; |
---|
| 742 | } |
---|
| 743 | default: { |
---|
| 744 | primaryexp(ls, v); |
---|
| 745 | break; |
---|
| 746 | } |
---|
| 747 | } |
---|
| 748 | } |
---|
| 749 | |
---|
| 750 | |
---|
| 751 | static UnOpr getunopr (int op) { |
---|
| 752 | switch (op) { |
---|
| 753 | case TK_NOT: return OPR_NOT; |
---|
| 754 | case '-': return OPR_MINUS; |
---|
| 755 | default: return OPR_NOUNOPR; |
---|
| 756 | } |
---|
| 757 | } |
---|
| 758 | |
---|
| 759 | |
---|
| 760 | static BinOpr getbinopr (int op) { |
---|
| 761 | switch (op) { |
---|
| 762 | case '+': return OPR_ADD; |
---|
| 763 | case '-': return OPR_SUB; |
---|
| 764 | case '*': return OPR_MULT; |
---|
| 765 | case '/': return OPR_DIV; |
---|
| 766 | case '^': return OPR_POW; |
---|
| 767 | case TK_CONCAT: return OPR_CONCAT; |
---|
| 768 | case TK_NE: return OPR_NE; |
---|
| 769 | case TK_EQ: return OPR_EQ; |
---|
| 770 | case '<': return OPR_LT; |
---|
| 771 | case TK_LE: return OPR_LE; |
---|
| 772 | case '>': return OPR_GT; |
---|
| 773 | case TK_GE: return OPR_GE; |
---|
| 774 | case TK_AND: return OPR_AND; |
---|
| 775 | case TK_OR: return OPR_OR; |
---|
| 776 | default: return OPR_NOBINOPR; |
---|
| 777 | } |
---|
| 778 | } |
---|
| 779 | |
---|
| 780 | |
---|
| 781 | static const struct { |
---|
| 782 | lu_byte left; /* left priority for each binary operator */ |
---|
| 783 | lu_byte right; /* right priority */ |
---|
| 784 | } priority[] = { /* ORDER OPR */ |
---|
| 785 | {6, 6}, {6, 6}, {7, 7}, {7, 7}, /* arithmetic */ |
---|
| 786 | {10, 9}, {5, 4}, /* power and concat (right associative) */ |
---|
| 787 | {3, 3}, {3, 3}, /* equality */ |
---|
| 788 | {3, 3}, {3, 3}, {3, 3}, {3, 3}, /* order */ |
---|
| 789 | {2, 2}, {1, 1} /* logical (and/or) */ |
---|
| 790 | }; |
---|
| 791 | |
---|
| 792 | #define UNARY_PRIORITY 8 /* priority for unary operators */ |
---|
| 793 | |
---|
| 794 | |
---|
| 795 | /* |
---|
| 796 | ** subexpr -> (simplexep | unop subexpr) { binop subexpr } |
---|
| 797 | ** where `binop' is any binary operator with a priority higher than `limit' |
---|
| 798 | */ |
---|
| 799 | static BinOpr subexpr (LexState *ls, expdesc *v, int limit) { |
---|
| 800 | BinOpr op; |
---|
| 801 | UnOpr uop; |
---|
| 802 | enterlevel(ls); |
---|
| 803 | uop = getunopr(ls->t.token); |
---|
| 804 | if (uop != OPR_NOUNOPR) { |
---|
| 805 | next(ls); |
---|
| 806 | subexpr(ls, v, UNARY_PRIORITY); |
---|
| 807 | luaK_prefix(ls->fs, uop, v); |
---|
| 808 | } |
---|
| 809 | else simpleexp(ls, v); |
---|
| 810 | /* expand while operators have priorities higher than `limit' */ |
---|
| 811 | op = getbinopr(ls->t.token); |
---|
| 812 | while (op != OPR_NOBINOPR && cast(int, priority[op].left) > limit) { |
---|
| 813 | expdesc v2; |
---|
| 814 | BinOpr nextop; |
---|
| 815 | next(ls); |
---|
| 816 | luaK_infix(ls->fs, op, v); |
---|
| 817 | /* read sub-expression with higher priority */ |
---|
| 818 | nextop = subexpr(ls, &v2, cast(int, priority[op].right)); |
---|
| 819 | luaK_posfix(ls->fs, op, v, &v2); |
---|
| 820 | op = nextop; |
---|
| 821 | } |
---|
| 822 | leavelevel(ls); |
---|
| 823 | return op; /* return first untreated operator */ |
---|
| 824 | } |
---|
| 825 | |
---|
| 826 | |
---|
| 827 | static void expr (LexState *ls, expdesc *v) { |
---|
| 828 | subexpr(ls, v, -1); |
---|
| 829 | } |
---|
| 830 | |
---|
| 831 | /* }==================================================================== */ |
---|
| 832 | |
---|
| 833 | |
---|
| 834 | |
---|
| 835 | /* |
---|
| 836 | ** {====================================================================== |
---|
| 837 | ** Rules for Statements |
---|
| 838 | ** ======================================================================= |
---|
| 839 | */ |
---|
| 840 | |
---|
| 841 | |
---|
| 842 | static int block_follow (int token) { |
---|
| 843 | switch (token) { |
---|
| 844 | case TK_ELSE: case TK_ELSEIF: case TK_END: |
---|
| 845 | case TK_UNTIL: case TK_EOS: |
---|
| 846 | return 1; |
---|
| 847 | default: return 0; |
---|
| 848 | } |
---|
| 849 | } |
---|
| 850 | |
---|
| 851 | |
---|
| 852 | static void block (LexState *ls) { |
---|
| 853 | /* block -> chunk */ |
---|
| 854 | FuncState *fs = ls->fs; |
---|
| 855 | BlockCnt bl; |
---|
| 856 | enterblock(fs, &bl, 0); |
---|
| 857 | chunk(ls); |
---|
| 858 | lua_assert(bl.breaklist == NO_JUMP); |
---|
| 859 | leaveblock(fs); |
---|
| 860 | } |
---|
| 861 | |
---|
| 862 | |
---|
| 863 | /* |
---|
| 864 | ** structure to chain all variables in the left-hand side of an |
---|
| 865 | ** assignment |
---|
| 866 | */ |
---|
| 867 | struct LHS_assign { |
---|
| 868 | struct LHS_assign *prev; |
---|
| 869 | expdesc v; /* variable (global, local, upvalue, or indexed) */ |
---|
| 870 | }; |
---|
| 871 | |
---|
| 872 | |
---|
| 873 | /* |
---|
| 874 | ** check whether, in an assignment to a local variable, the local variable |
---|
| 875 | ** is needed in a previous assignment (to a table). If so, save original |
---|
| 876 | ** local value in a safe place and use this safe copy in the previous |
---|
| 877 | ** assignment. |
---|
| 878 | */ |
---|
| 879 | static void check_conflict (LexState *ls, struct LHS_assign *lh, expdesc *v) { |
---|
| 880 | FuncState *fs = ls->fs; |
---|
| 881 | int extra = fs->freereg; /* eventual position to save local variable */ |
---|
| 882 | int conflict = 0; |
---|
| 883 | for (; lh; lh = lh->prev) { |
---|
| 884 | if (lh->v.k == VINDEXED) { |
---|
| 885 | if (lh->v.info == v->info) { /* conflict? */ |
---|
| 886 | conflict = 1; |
---|
| 887 | lh->v.info = extra; /* previous assignment will use safe copy */ |
---|
| 888 | } |
---|
| 889 | if (lh->v.aux == v->info) { /* conflict? */ |
---|
| 890 | conflict = 1; |
---|
| 891 | lh->v.aux = extra; /* previous assignment will use safe copy */ |
---|
| 892 | } |
---|
| 893 | } |
---|
| 894 | } |
---|
| 895 | if (conflict) { |
---|
| 896 | luaK_codeABC(fs, OP_MOVE, fs->freereg, v->info, 0); /* make copy */ |
---|
| 897 | luaK_reserveregs(fs, 1); |
---|
| 898 | } |
---|
| 899 | } |
---|
| 900 | |
---|
| 901 | |
---|
| 902 | static void assignment (LexState *ls, struct LHS_assign *lh, int nvars) { |
---|
| 903 | expdesc e; |
---|
| 904 | check_condition(ls, VLOCAL <= lh->v.k && lh->v.k <= VINDEXED, |
---|
| 905 | "syntax error"); |
---|
| 906 | if (testnext(ls, ',')) { /* assignment -> `,' primaryexp assignment */ |
---|
| 907 | struct LHS_assign nv; |
---|
| 908 | nv.prev = lh; |
---|
| 909 | primaryexp(ls, &nv.v); |
---|
| 910 | if (nv.v.k == VLOCAL) |
---|
| 911 | check_conflict(ls, lh, &nv.v); |
---|
| 912 | assignment(ls, &nv, nvars+1); |
---|
| 913 | } |
---|
| 914 | else { /* assignment -> `=' explist1 */ |
---|
| 915 | int nexps; |
---|
| 916 | check(ls, '='); |
---|
| 917 | nexps = explist1(ls, &e); |
---|
| 918 | if (nexps != nvars) { |
---|
| 919 | adjust_assign(ls, nvars, nexps, &e); |
---|
| 920 | if (nexps > nvars) |
---|
| 921 | ls->fs->freereg -= nexps - nvars; /* remove extra values */ |
---|
| 922 | } |
---|
| 923 | else { |
---|
| 924 | luaK_setcallreturns(ls->fs, &e, 1); /* close last expression */ |
---|
| 925 | luaK_storevar(ls->fs, &lh->v, &e); |
---|
| 926 | return; /* avoid default */ |
---|
| 927 | } |
---|
| 928 | } |
---|
| 929 | init_exp(&e, VNONRELOC, ls->fs->freereg-1); /* default assignment */ |
---|
| 930 | luaK_storevar(ls->fs, &lh->v, &e); |
---|
| 931 | } |
---|
| 932 | |
---|
| 933 | |
---|
| 934 | static void cond (LexState *ls, expdesc *v) { |
---|
| 935 | /* cond -> exp */ |
---|
| 936 | expr(ls, v); /* read condition */ |
---|
| 937 | if (v->k == VNIL) v->k = VFALSE; /* `falses' are all equal here */ |
---|
| 938 | luaK_goiftrue(ls->fs, v); |
---|
| 939 | luaK_patchtohere(ls->fs, v->t); |
---|
| 940 | } |
---|
| 941 | |
---|
| 942 | |
---|
| 943 | /* |
---|
| 944 | ** The while statement optimizes its code by coding the condition |
---|
| 945 | ** after its body (and thus avoiding one jump in the loop). |
---|
| 946 | */ |
---|
| 947 | |
---|
| 948 | /* |
---|
| 949 | ** maximum size of expressions for optimizing `while' code |
---|
| 950 | */ |
---|
| 951 | #ifndef MAXEXPWHILE |
---|
| 952 | #define MAXEXPWHILE 100 |
---|
| 953 | #endif |
---|
| 954 | |
---|
| 955 | /* |
---|
| 956 | ** the call `luaK_goiffalse' may grow the size of an expression by |
---|
| 957 | ** at most this: |
---|
| 958 | */ |
---|
| 959 | #define EXTRAEXP 5 |
---|
| 960 | |
---|
| 961 | static void whilestat (LexState *ls, int line) { |
---|
| 962 | /* whilestat -> WHILE cond DO block END */ |
---|
| 963 | Instruction codeexp[MAXEXPWHILE + EXTRAEXP]; |
---|
| 964 | int lineexp; |
---|
| 965 | int i; |
---|
| 966 | int sizeexp; |
---|
| 967 | FuncState *fs = ls->fs; |
---|
| 968 | int whileinit, blockinit, expinit; |
---|
| 969 | expdesc v; |
---|
| 970 | BlockCnt bl; |
---|
| 971 | next(ls); /* skip WHILE */ |
---|
| 972 | whileinit = luaK_jump(fs); /* jump to condition (which will be moved) */ |
---|
| 973 | expinit = luaK_getlabel(fs); |
---|
| 974 | expr(ls, &v); /* parse condition */ |
---|
| 975 | if (v.k == VK) v.k = VTRUE; /* `trues' are all equal here */ |
---|
| 976 | lineexp = ls->linenumber; |
---|
| 977 | luaK_goiffalse(fs, &v); |
---|
| 978 | luaK_concat(fs, &v.f, fs->jpc); |
---|
| 979 | fs->jpc = NO_JUMP; |
---|
| 980 | sizeexp = fs->pc - expinit; /* size of expression code */ |
---|
| 981 | if (sizeexp > MAXEXPWHILE) |
---|
| 982 | luaX_syntaxerror(ls, "`while' condition too complex"); |
---|
| 983 | for (i = 0; i < sizeexp; i++) /* save `exp' code */ |
---|
| 984 | codeexp[i] = fs->f->code[expinit + i]; |
---|
| 985 | fs->pc = expinit; /* remove `exp' code */ |
---|
| 986 | enterblock(fs, &bl, 1); |
---|
| 987 | check(ls, TK_DO); |
---|
| 988 | blockinit = luaK_getlabel(fs); |
---|
| 989 | block(ls); |
---|
| 990 | luaK_patchtohere(fs, whileinit); /* initial jump jumps to here */ |
---|
| 991 | /* move `exp' back to code */ |
---|
| 992 | if (v.t != NO_JUMP) v.t += fs->pc - expinit; |
---|
| 993 | if (v.f != NO_JUMP) v.f += fs->pc - expinit; |
---|
| 994 | for (i=0; i<sizeexp; i++) |
---|
| 995 | luaK_code(fs, codeexp[i], lineexp); |
---|
| 996 | check_match(ls, TK_END, TK_WHILE, line); |
---|
| 997 | leaveblock(fs); |
---|
| 998 | luaK_patchlist(fs, v.t, blockinit); /* true conditions go back to loop */ |
---|
| 999 | luaK_patchtohere(fs, v.f); /* false conditions finish the loop */ |
---|
| 1000 | } |
---|
| 1001 | |
---|
| 1002 | |
---|
| 1003 | static void repeatstat (LexState *ls, int line) { |
---|
| 1004 | /* repeatstat -> REPEAT block UNTIL cond */ |
---|
| 1005 | FuncState *fs = ls->fs; |
---|
| 1006 | int repeat_init = luaK_getlabel(fs); |
---|
| 1007 | expdesc v; |
---|
| 1008 | BlockCnt bl; |
---|
| 1009 | enterblock(fs, &bl, 1); |
---|
| 1010 | next(ls); |
---|
| 1011 | block(ls); |
---|
| 1012 | check_match(ls, TK_UNTIL, TK_REPEAT, line); |
---|
| 1013 | cond(ls, &v); |
---|
| 1014 | luaK_patchlist(fs, v.f, repeat_init); |
---|
| 1015 | leaveblock(fs); |
---|
| 1016 | } |
---|
| 1017 | |
---|
| 1018 | |
---|
| 1019 | static int exp1 (LexState *ls) { |
---|
| 1020 | expdesc e; |
---|
| 1021 | int k; |
---|
| 1022 | expr(ls, &e); |
---|
| 1023 | k = e.k; |
---|
| 1024 | luaK_exp2nextreg(ls->fs, &e); |
---|
| 1025 | return k; |
---|
| 1026 | } |
---|
| 1027 | |
---|
| 1028 | |
---|
| 1029 | static void forbody (LexState *ls, int base, int line, int nvars, int isnum) { |
---|
| 1030 | BlockCnt bl; |
---|
| 1031 | FuncState *fs = ls->fs; |
---|
| 1032 | int prep, endfor; |
---|
| 1033 | adjustlocalvars(ls, nvars); /* scope for all variables */ |
---|
| 1034 | check(ls, TK_DO); |
---|
| 1035 | enterblock(fs, &bl, 1); /* loop block */ |
---|
| 1036 | prep = luaK_getlabel(fs); |
---|
| 1037 | block(ls); |
---|
| 1038 | luaK_patchtohere(fs, prep-1); |
---|
| 1039 | endfor = (isnum) ? luaK_codeAsBx(fs, OP_FORLOOP, base, NO_JUMP) : |
---|
| 1040 | luaK_codeABC(fs, OP_TFORLOOP, base, 0, nvars - 3); |
---|
| 1041 | luaK_fixline(fs, line); /* pretend that `OP_FOR' starts the loop */ |
---|
| 1042 | luaK_patchlist(fs, (isnum) ? endfor : luaK_jump(fs), prep); |
---|
| 1043 | leaveblock(fs); |
---|
| 1044 | } |
---|
| 1045 | |
---|
| 1046 | |
---|
| 1047 | static void fornum (LexState *ls, TString *varname, int line) { |
---|
| 1048 | /* fornum -> NAME = exp1,exp1[,exp1] DO body */ |
---|
| 1049 | FuncState *fs = ls->fs; |
---|
| 1050 | int base = fs->freereg; |
---|
| 1051 | new_localvar(ls, varname, 0); |
---|
| 1052 | new_localvarstr(ls, "(for limit)", 1); |
---|
| 1053 | new_localvarstr(ls, "(for step)", 2); |
---|
| 1054 | check(ls, '='); |
---|
| 1055 | exp1(ls); /* initial value */ |
---|
| 1056 | check(ls, ','); |
---|
| 1057 | exp1(ls); /* limit */ |
---|
| 1058 | if (testnext(ls, ',')) |
---|
| 1059 | exp1(ls); /* optional step */ |
---|
| 1060 | else { /* default step = 1 */ |
---|
| 1061 | luaK_codeABx(fs, OP_LOADK, fs->freereg, luaK_numberK(fs, 1)); |
---|
| 1062 | luaK_reserveregs(fs, 1); |
---|
| 1063 | } |
---|
| 1064 | luaK_codeABC(fs, OP_SUB, fs->freereg - 3, fs->freereg - 3, fs->freereg - 1); |
---|
| 1065 | luaK_jump(fs); |
---|
| 1066 | forbody(ls, base, line, 3, 1); |
---|
| 1067 | } |
---|
| 1068 | |
---|
| 1069 | |
---|
| 1070 | static void forlist (LexState *ls, TString *indexname) { |
---|
| 1071 | /* forlist -> NAME {,NAME} IN explist1 DO body */ |
---|
| 1072 | FuncState *fs = ls->fs; |
---|
| 1073 | expdesc e; |
---|
| 1074 | int nvars = 0; |
---|
| 1075 | int line; |
---|
| 1076 | int base = fs->freereg; |
---|
| 1077 | new_localvarstr(ls, "(for generator)", nvars++); |
---|
| 1078 | new_localvarstr(ls, "(for state)", nvars++); |
---|
| 1079 | new_localvar(ls, indexname, nvars++); |
---|
| 1080 | while (testnext(ls, ',')) |
---|
| 1081 | new_localvar(ls, str_checkname(ls), nvars++); |
---|
| 1082 | check(ls, TK_IN); |
---|
| 1083 | line = ls->linenumber; |
---|
| 1084 | adjust_assign(ls, nvars, explist1(ls, &e), &e); |
---|
| 1085 | luaK_checkstack(fs, 3); /* extra space to call generator */ |
---|
| 1086 | luaK_codeAsBx(fs, OP_TFORPREP, base, NO_JUMP); |
---|
| 1087 | forbody(ls, base, line, nvars, 0); |
---|
| 1088 | } |
---|
| 1089 | |
---|
| 1090 | |
---|
| 1091 | static void forstat (LexState *ls, int line) { |
---|
| 1092 | /* forstat -> fornum | forlist */ |
---|
| 1093 | FuncState *fs = ls->fs; |
---|
| 1094 | TString *varname; |
---|
| 1095 | BlockCnt bl; |
---|
| 1096 | enterblock(fs, &bl, 0); /* block to control variable scope */ |
---|
| 1097 | next(ls); /* skip `for' */ |
---|
| 1098 | varname = str_checkname(ls); /* first variable name */ |
---|
| 1099 | switch (ls->t.token) { |
---|
| 1100 | case '=': fornum(ls, varname, line); break; |
---|
| 1101 | case ',': case TK_IN: forlist(ls, varname); break; |
---|
| 1102 | default: luaX_syntaxerror(ls, "`=' or `in' expected"); |
---|
| 1103 | } |
---|
| 1104 | check_match(ls, TK_END, TK_FOR, line); |
---|
| 1105 | leaveblock(fs); |
---|
| 1106 | } |
---|
| 1107 | |
---|
| 1108 | |
---|
| 1109 | static void test_then_block (LexState *ls, expdesc *v) { |
---|
| 1110 | /* test_then_block -> [IF | ELSEIF] cond THEN block */ |
---|
| 1111 | next(ls); /* skip IF or ELSEIF */ |
---|
| 1112 | cond(ls, v); |
---|
| 1113 | check(ls, TK_THEN); |
---|
| 1114 | block(ls); /* `then' part */ |
---|
| 1115 | } |
---|
| 1116 | |
---|
| 1117 | |
---|
| 1118 | static void ifstat (LexState *ls, int line) { |
---|
| 1119 | /* ifstat -> IF cond THEN block {ELSEIF cond THEN block} [ELSE block] END */ |
---|
| 1120 | FuncState *fs = ls->fs; |
---|
| 1121 | expdesc v; |
---|
| 1122 | int escapelist = NO_JUMP; |
---|
| 1123 | test_then_block(ls, &v); /* IF cond THEN block */ |
---|
| 1124 | while (ls->t.token == TK_ELSEIF) { |
---|
| 1125 | luaK_concat(fs, &escapelist, luaK_jump(fs)); |
---|
| 1126 | luaK_patchtohere(fs, v.f); |
---|
| 1127 | test_then_block(ls, &v); /* ELSEIF cond THEN block */ |
---|
| 1128 | } |
---|
| 1129 | if (ls->t.token == TK_ELSE) { |
---|
| 1130 | luaK_concat(fs, &escapelist, luaK_jump(fs)); |
---|
| 1131 | luaK_patchtohere(fs, v.f); |
---|
| 1132 | next(ls); /* skip ELSE (after patch, for correct line info) */ |
---|
| 1133 | block(ls); /* `else' part */ |
---|
| 1134 | } |
---|
| 1135 | else |
---|
| 1136 | luaK_concat(fs, &escapelist, v.f); |
---|
| 1137 | luaK_patchtohere(fs, escapelist); |
---|
| 1138 | check_match(ls, TK_END, TK_IF, line); |
---|
| 1139 | } |
---|
| 1140 | |
---|
| 1141 | |
---|
| 1142 | static void localfunc (LexState *ls) { |
---|
| 1143 | expdesc v, b; |
---|
| 1144 | FuncState *fs = ls->fs; |
---|
| 1145 | new_localvar(ls, str_checkname(ls), 0); |
---|
| 1146 | init_exp(&v, VLOCAL, fs->freereg); |
---|
| 1147 | luaK_reserveregs(fs, 1); |
---|
| 1148 | adjustlocalvars(ls, 1); |
---|
| 1149 | body(ls, &b, 0, ls->linenumber); |
---|
| 1150 | luaK_storevar(fs, &v, &b); |
---|
| 1151 | /* debug information will only see the variable after this point! */ |
---|
| 1152 | getlocvar(fs, fs->nactvar - 1).startpc = fs->pc; |
---|
| 1153 | } |
---|
| 1154 | |
---|
| 1155 | |
---|
| 1156 | static void localstat (LexState *ls) { |
---|
| 1157 | /* stat -> LOCAL NAME {`,' NAME} [`=' explist1] */ |
---|
| 1158 | int nvars = 0; |
---|
| 1159 | int nexps; |
---|
| 1160 | expdesc e; |
---|
| 1161 | do { |
---|
| 1162 | new_localvar(ls, str_checkname(ls), nvars++); |
---|
| 1163 | } while (testnext(ls, ',')); |
---|
| 1164 | if (testnext(ls, '=')) |
---|
| 1165 | nexps = explist1(ls, &e); |
---|
| 1166 | else { |
---|
| 1167 | e.k = VVOID; |
---|
| 1168 | nexps = 0; |
---|
| 1169 | } |
---|
| 1170 | adjust_assign(ls, nvars, nexps, &e); |
---|
| 1171 | adjustlocalvars(ls, nvars); |
---|
| 1172 | } |
---|
| 1173 | |
---|
| 1174 | |
---|
| 1175 | static int funcname (LexState *ls, expdesc *v) { |
---|
| 1176 | /* funcname -> NAME {field} [`:' NAME] */ |
---|
| 1177 | int needself = 0; |
---|
| 1178 | singlevar(ls, v, 1); |
---|
| 1179 | while (ls->t.token == '.') |
---|
| 1180 | luaY_field(ls, v); |
---|
| 1181 | if (ls->t.token == ':') { |
---|
| 1182 | needself = 1; |
---|
| 1183 | luaY_field(ls, v); |
---|
| 1184 | } |
---|
| 1185 | return needself; |
---|
| 1186 | } |
---|
| 1187 | |
---|
| 1188 | |
---|
| 1189 | static void funcstat (LexState *ls, int line) { |
---|
| 1190 | /* funcstat -> FUNCTION funcname body */ |
---|
| 1191 | int needself; |
---|
| 1192 | expdesc v, b; |
---|
| 1193 | next(ls); /* skip FUNCTION */ |
---|
| 1194 | needself = funcname(ls, &v); |
---|
| 1195 | body(ls, &b, needself, line); |
---|
| 1196 | luaK_storevar(ls->fs, &v, &b); |
---|
| 1197 | luaK_fixline(ls->fs, line); /* definition `happens' in the first line */ |
---|
| 1198 | } |
---|
| 1199 | |
---|
| 1200 | |
---|
| 1201 | static void exprstat (LexState *ls) { |
---|
| 1202 | /* stat -> func | assignment */ |
---|
| 1203 | FuncState *fs = ls->fs; |
---|
| 1204 | struct LHS_assign v; |
---|
| 1205 | primaryexp(ls, &v.v); |
---|
| 1206 | if (v.v.k == VCALL) { /* stat -> func */ |
---|
| 1207 | luaK_setcallreturns(fs, &v.v, 0); /* call statement uses no results */ |
---|
| 1208 | } |
---|
| 1209 | else { /* stat -> assignment */ |
---|
| 1210 | v.prev = NULL; |
---|
| 1211 | assignment(ls, &v, 1); |
---|
| 1212 | } |
---|
| 1213 | } |
---|
| 1214 | |
---|
| 1215 | |
---|
| 1216 | static void retstat (LexState *ls) { |
---|
| 1217 | /* stat -> RETURN explist */ |
---|
| 1218 | FuncState *fs = ls->fs; |
---|
| 1219 | expdesc e; |
---|
| 1220 | int first, nret; /* registers with returned values */ |
---|
| 1221 | next(ls); /* skip RETURN */ |
---|
| 1222 | if (block_follow(ls->t.token) || ls->t.token == ';') |
---|
| 1223 | first = nret = 0; /* return no values */ |
---|
| 1224 | else { |
---|
| 1225 | nret = explist1(ls, &e); /* optional return values */ |
---|
| 1226 | if (e.k == VCALL) { |
---|
| 1227 | luaK_setcallreturns(fs, &e, LUA_MULTRET); |
---|
| 1228 | if (nret == 1) { /* tail call? */ |
---|
| 1229 | SET_OPCODE(getcode(fs,&e), OP_TAILCALL); |
---|
| 1230 | lua_assert(GETARG_A(getcode(fs,&e)) == fs->nactvar); |
---|
| 1231 | } |
---|
| 1232 | first = fs->nactvar; |
---|
| 1233 | nret = LUA_MULTRET; /* return all values */ |
---|
| 1234 | } |
---|
| 1235 | else { |
---|
| 1236 | if (nret == 1) /* only one single value? */ |
---|
| 1237 | first = luaK_exp2anyreg(fs, &e); |
---|
| 1238 | else { |
---|
| 1239 | luaK_exp2nextreg(fs, &e); /* values must go to the `stack' */ |
---|
| 1240 | first = fs->nactvar; /* return all `active' values */ |
---|
| 1241 | lua_assert(nret == fs->freereg - first); |
---|
| 1242 | } |
---|
| 1243 | } |
---|
| 1244 | } |
---|
| 1245 | luaK_codeABC(fs, OP_RETURN, first, nret+1, 0); |
---|
| 1246 | } |
---|
| 1247 | |
---|
| 1248 | |
---|
| 1249 | static void breakstat (LexState *ls) { |
---|
| 1250 | /* stat -> BREAK [NAME] */ |
---|
| 1251 | FuncState *fs = ls->fs; |
---|
| 1252 | BlockCnt *bl = fs->bl; |
---|
| 1253 | int upval = 0; |
---|
| 1254 | next(ls); /* skip BREAK */ |
---|
| 1255 | while (bl && !bl->isbreakable) { |
---|
| 1256 | upval |= bl->upval; |
---|
| 1257 | bl = bl->previous; |
---|
| 1258 | } |
---|
| 1259 | if (!bl) |
---|
| 1260 | luaX_syntaxerror(ls, "no loop to break"); |
---|
| 1261 | if (upval) |
---|
| 1262 | luaK_codeABC(fs, OP_CLOSE, bl->nactvar, 0, 0); |
---|
| 1263 | luaK_concat(fs, &bl->breaklist, luaK_jump(fs)); |
---|
| 1264 | } |
---|
| 1265 | |
---|
| 1266 | |
---|
| 1267 | static int statement (LexState *ls) { |
---|
| 1268 | int line = ls->linenumber; /* may be needed for error messages */ |
---|
| 1269 | switch (ls->t.token) { |
---|
| 1270 | case TK_IF: { /* stat -> ifstat */ |
---|
| 1271 | ifstat(ls, line); |
---|
| 1272 | return 0; |
---|
| 1273 | } |
---|
| 1274 | case TK_WHILE: { /* stat -> whilestat */ |
---|
| 1275 | whilestat(ls, line); |
---|
| 1276 | return 0; |
---|
| 1277 | } |
---|
| 1278 | case TK_DO: { /* stat -> DO block END */ |
---|
| 1279 | next(ls); /* skip DO */ |
---|
| 1280 | block(ls); |
---|
| 1281 | check_match(ls, TK_END, TK_DO, line); |
---|
| 1282 | return 0; |
---|
| 1283 | } |
---|
| 1284 | case TK_FOR: { /* stat -> forstat */ |
---|
| 1285 | forstat(ls, line); |
---|
| 1286 | return 0; |
---|
| 1287 | } |
---|
| 1288 | case TK_REPEAT: { /* stat -> repeatstat */ |
---|
| 1289 | repeatstat(ls, line); |
---|
| 1290 | return 0; |
---|
| 1291 | } |
---|
| 1292 | case TK_FUNCTION: { |
---|
| 1293 | funcstat(ls, line); /* stat -> funcstat */ |
---|
| 1294 | return 0; |
---|
| 1295 | } |
---|
| 1296 | case TK_LOCAL: { /* stat -> localstat */ |
---|
| 1297 | next(ls); /* skip LOCAL */ |
---|
| 1298 | if (testnext(ls, TK_FUNCTION)) /* local function? */ |
---|
| 1299 | localfunc(ls); |
---|
| 1300 | else |
---|
| 1301 | localstat(ls); |
---|
| 1302 | return 0; |
---|
| 1303 | } |
---|
| 1304 | case TK_RETURN: { /* stat -> retstat */ |
---|
| 1305 | retstat(ls); |
---|
| 1306 | return 1; /* must be last statement */ |
---|
| 1307 | } |
---|
| 1308 | case TK_BREAK: { /* stat -> breakstat */ |
---|
| 1309 | breakstat(ls); |
---|
| 1310 | return 1; /* must be last statement */ |
---|
| 1311 | } |
---|
| 1312 | default: { |
---|
| 1313 | exprstat(ls); |
---|
| 1314 | return 0; /* to avoid warnings */ |
---|
| 1315 | } |
---|
| 1316 | } |
---|
| 1317 | } |
---|
| 1318 | |
---|
| 1319 | |
---|
| 1320 | static void chunk (LexState *ls) { |
---|
| 1321 | /* chunk -> { stat [`;'] } */ |
---|
| 1322 | int islast = 0; |
---|
| 1323 | enterlevel(ls); |
---|
| 1324 | while (!islast && !block_follow(ls->t.token)) { |
---|
| 1325 | islast = statement(ls); |
---|
| 1326 | testnext(ls, ';'); |
---|
| 1327 | lua_assert(ls->fs->freereg >= ls->fs->nactvar); |
---|
| 1328 | ls->fs->freereg = ls->fs->nactvar; /* free registers */ |
---|
| 1329 | } |
---|
| 1330 | leavelevel(ls); |
---|
| 1331 | } |
---|
| 1332 | |
---|
| 1333 | /* }====================================================================== */ |
---|