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better documentation for constructor syntax

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This commit is contained in:
Roberto Ierusalimschy 2009-10-14 13:43:11 -03:00
parent 6e415e9387
commit 1448e736f0
1 changed files with 34 additions and 26 deletions
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60
lparser.c
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@ -1,5 +1,5 @@
/*
** $Id: lparser.c,v 2.69 2009/10/11 20:02:19 roberto Exp roberto $
** $Id: lparser.c,v 2.70 2009/10/13 19:35:42 roberto Exp roberto $
** Lua Parser
** See Copyright Notice in lua.h
*/
@ -440,8 +440,8 @@ Proto *luaY_parser (lua_State *L, ZIO *z, Mbuffer *buff, Varlist *varl,
/*============================================================*/
static void field (LexState *ls, expdesc *v) {
/* field -> ['.' | ':'] NAME */
static void fieldsel (LexState *ls, expdesc *v) {
/* fieldsel -> ['.' | ':'] NAME */
FuncState *fs = ls->fs;
expdesc key;
luaK_exp2anyreg(fs, v);
@ -524,6 +524,7 @@ static void lastlistfield (FuncState *fs, struct ConsControl *cc) {
static void listfield (LexState *ls, struct ConsControl *cc) {
/* listfield -> exp */
expr(ls, &cc->v);
luaY_checklimit(ls->fs, cc->na, MAX_INT, "items in a constructor");
cc->na++;
@ -531,8 +532,31 @@ static void listfield (LexState *ls, struct ConsControl *cc) {
}
static void field (LexState *ls, struct ConsControl *cc) {
/* field -> listfield | recfield */
switch(ls->t.token) {
case TK_NAME: { /* may be 'listfield' or 'recfield' */
if (luaX_lookahead(ls) != '=') /* expression? */
listfield(ls, cc);
else
recfield(ls, cc);
break;
}
case '[': {
recfield(ls, cc);
break;
}
default: {
listfield(ls, cc);
break;
}
}
}
static void constructor (LexState *ls, expdesc *t) {
/* constructor -> ?? */
/* constructor -> '{' [ field { sep field } [sep] ] '}'
sep -> ',' | ';' */
FuncState *fs = ls->fs;
int line = ls->linenumber;
int pc = luaK_codeABC(fs, OP_NEWTABLE, 0, 0, 0);
@ -547,23 +571,7 @@ static void constructor (LexState *ls, expdesc *t) {
lua_assert(cc.v.k == VVOID || cc.tostore > 0);
if (ls->t.token == '}') break;
closelistfield(fs, &cc);
switch(ls->t.token) {
case TK_NAME: { /* may be listfields or recfields */
if (luaX_lookahead(ls) != '=') /* expression? */
listfield(ls, &cc);
else
recfield(ls, &cc);
break;
}
case '[': { /* constructor_item -> recfield */
recfield(ls, &cc);
break;
}
default: { /* constructor_part -> listfield */
listfield(ls, &cc);
break;
}
}
field(ls, &cc);
} while (testnext(ls, ',') || testnext(ls, ';'));
check_match(ls, '}', '{', line);
lastlistfield(fs, &cc);
@ -725,8 +733,8 @@ static void primaryexp (LexState *ls, expdesc *v) {
prefixexp(ls, v);
for (;;) {
switch (ls->t.token) {
case '.': { /* field */
field(ls, v);
case '.': { /* fieldsel */
fieldsel(ls, v);
break;
}
case '[': { /* `[' exp1 `]' */
@ -1233,14 +1241,14 @@ static void localstat (LexState *ls) {
static int funcname (LexState *ls, expdesc *v) {
/* funcname -> NAME {field} [`:' NAME] */
/* funcname -> NAME {fieldsel} [`:' NAME] */
int needself = 0;
singlevar(ls, v);
while (ls->t.token == '.')
field(ls, v);
fieldsel(ls, v);
if (ls->t.token == ':') {
needself = 1;
field(ls, v);
fieldsel(ls, v);
}
return needself;
}