Re: compound assignment patch for 5.4.0-beta

[Dave Hayden <dave@...>]

On Dec 26, 2019, at 7:27 PM, Dave Hayden <dave@panic.com> wrote:
> 
> Hopefully this is useful to others, and please let me know what I did wrong! :)

Whoops! I bungled an assignment in the left-hand list case. Here’s that fixed, before it gives anyone any grief:


diff -r lua-5.4.0-beta/src/llex.c lua-5.4-test/src/llex.c
455a456
>         if (check_next1(ls, '=')) return TK_MINUSEQ;
491c492,495
<         else if (check_next1(ls, '<')) return TK_SHL;
---
>         else if (check_next1(ls, '<')) {
>           if ( check_next1(ls, '=') ) return TK_SHLEQ;
>           else return TK_SHL;
>         }
497c501,504
<         else if (check_next1(ls, '>')) return TK_SHR;
---
>         else if (check_next1(ls, '>')) {
>           if ( check_next1(ls, '=') ) return TK_SHREQ;
>           else return TK_SHR;
>         }
502a510
>         if (check_next1(ls, '=')) return TK_DIVEQ;
504a513,537
>       case '+': {
>         next(ls);
>         if (check_next1(ls, '=')) return TK_PLUSEQ;
>         else return '+';
>       }
>       case '*': {
>         next(ls);
>         if (check_next1(ls, '=')) return TK_MULTEQ;
>         else return '*';
>       }
>       case '&': {
>         next(ls);
>         if (check_next1(ls, '=')) return TK_BANDEQ;
>         else return '*';
>       }
>       case '|': {
>         next(ls);
>         if (check_next1(ls, '=')) return TK_BOREQ;
>         else return '|';
>       }
>       case '^': {
>         next(ls);
>         if (check_next1(ls, '=')) return TK_BXOREQ;
>         else return '^';
>       }
diff -r lua-5.4.0-beta/src/llex.h lua-5.4-test/src/llex.h
36c36,37
<   TK_FLT, TK_INT, TK_NAME, TK_STRING
---
>   TK_FLT, TK_INT, TK_NAME, TK_STRING,
>   TK_PLUSEQ, TK_MINUSEQ, TK_MULTEQ, TK_DIVEQ, TK_SHLEQ, TK_SHREQ, TK_BANDEQ, TK_BOREQ, TK_BXOREQ
diff -r lua-5.4.0-beta/src/lparser.c lua-5.4-test/src/lparser.c
1208a1209,1219
>     // PANIC
>     case TK_PLUSEQ: return OPR_ADD;
>     case TK_MINUSEQ: return OPR_SUB;
>     case TK_MULTEQ: return OPR_MUL;
>     case TK_DIVEQ: return OPR_DIV;
>     case TK_SHLEQ: return OPR_SHL;
>     case TK_SHREQ: return OPR_SHR;
>     case TK_BANDEQ: return OPR_BAND;
>     case TK_BOREQ: return OPR_BOR;
>     case TK_BXOREQ: return OPR_BXOR;
>     // end PANIC
1347a1359,1404
> // PANIC
> 
> static void compound_assignment(LexState *ls, expdesc* v, int nvars) {
>   BinOpr op = getbinopr(ls->t.token);
>   FuncState * fs=ls->fs;
>   int tolevel=fs->nactvar;
>   int old_free=fs->freereg;
>   expdesc e,infix;
>   int line=ls->linenumber;
>   int nextra, i;
>   luaX_next(ls);
> 
>   /* create temporary local variables to lock up any registers needed
>      by VINDEXED lvalues. */
>   lu_byte top=fs->nactvar;
>   /* protect both the table and index result registers,
>   ** ensuring that they won't be overwritten prior to the
>   ** storevar calls. */
>   if(v->k==VINDEXED) {
>     if( /*!ISK( v->u.ind.t ) &&*/ v->u.ind.t >= top) {
>       top= v->u.ind.t+1;
>     }
>     if( /*!ISK( v->u.ind.idx ) &&*/ v->u.ind.idx >= top) {
>       top= v->u.ind.idx+1;
>     }
>   }
>   nextra=top-fs->nactvar;
>   if(nextra) {
>     for(i=0;i<nextra;i++) {
>       new_localvarliteral(ls,"(temp)");
>     }
>     adjustlocalvars(ls,nextra);
>   }
> 
>   infix = *v;
>   luaK_infix(fs,op,&infix);
>   expr(ls, &e);
>   luaK_posfix(fs, op, &infix, &e, line);
>   luaK_storevar(fs, v, &infix);
>   removevars(fs,tolevel);
> 
>   if(old_free<fs->freereg) {
>     fs->freereg=old_free;
>   }
> }
> 
1353c1410
< ** restassign -> ',' suffixedexp restassign | '=' explist
---
> ** restassign -> ',' suffixedexp restassign | '=' explist | opeq expr
1369,1372c1426,1427
<   else {  /* restassign -> '=' explist */
<     int nexps;
<     checknext(ls, '=');
<     nexps = explist(ls, &e);
---
>   else if (testnext(ls, '=')) {  /* restassign -> '=' explist */
>     int nexps = explist(ls, &e);
1378c1433
<       return;  /* avoid default */
---
>       return;
1380a1436,1439
>   else if ( ls->t.token >= TK_PLUSEQ && ls->t.token <= TK_BXOREQ ) { /* restassign -> opeq expr */
> 	  compound_assignment(ls,&lh->v,nvars);
>       return;
>   }
1384a1444
> // end PANIC
1819c1879
<   if (ls->t.token == '=' || ls->t.token == ',') { /* stat -> assignment ? */
---
>   if (ls->t.token == '=' || ls->t.token == ',' || (ls->t.token >= TK_PLUSEQ && ls->t.token <= TK_BXOREQ) ) { /* stat -> assignment ? */