negative numerals do not need a MINUSOPeration; go directly to contant

table.

lparser.c

@@ -1,5 +1,5 @@
 /*
-** $Id: lparser.c,v 1.8 1999/01/15 11:38:33 roberto Exp roberto $
+** $Id: lparser.c,v 1.9 1999/01/21 18:38:39 roberto Exp roberto $
 ** LL(1) Parser and code generator for Lua
 ** See Copyright Notice in lua.h
 */
@@ -123,7 +123,6 @@ static void parlist (LexState *ls);
 static void part (LexState *ls, constdesc *cd);
 static void recfield (LexState *ls);
 static void ret (LexState *ls);
-static void simpleexp (LexState *ls, vardesc *v);
 static void statlist (LexState *ls);
 static void var_or_func (LexState *ls, vardesc *v);
 static void var_or_func_tail (LexState *ls, vardesc *v);
@@ -262,7 +261,7 @@ static int real_constant (FuncState *fs, real r) {
 
 static void code_number (LexState *ls, real f) {
   int i;
-  if (f >= 0 && f <= (real)MAX_WORD && (real)(i=(int)f) == f)
+  if (0 <= f && f <= (real)MAX_WORD && (real)(i=(int)f) == f)
     code_oparg(ls, PUSHNUMBER, 3, i, 1);  /* f has a short integer value */
   else
     code_constant(ls, real_constant(ls->fs, f));
@@ -900,6 +899,9 @@ static int priority [POW+1] =  {5, 5, 1, 1, 1, 1, 1, 1, 2, 3, 3, 4, 4, 6};
 static OpCode opcodes [POW+1] = {NOTOP, MINUSOP, EQOP, NEQOP, GTOP, LTOP,
   LEOP, GEOP, CONCOP, ADDOP, SUBOP, MULTOP, DIVOP, POWOP};
 
+#define INDNOT		0
+#define INDMINUS	1
+
 #define MAXOPS	20
 
 typedef struct {
@@ -941,7 +943,7 @@ static void push (LexState *ls, stack_op *s, int op) {
 
 static void prefix (LexState *ls, stack_op *s) {
   while (ls->token == NOT || ls->token == '-') {
-    push(ls, s, ls->token==NOT?0:1);
+    push(ls, s, ls->token==NOT?INDNOT:INDMINUS);
     next(ls);
   }
 }
@@ -954,80 +956,85 @@ static void pop_to (LexState *ls, stack_op *s, int prio) {
   }
 }
 
-static void exp2 (LexState *ls, vardesc *v) {
-  stack_op s;
-  int op;
-  s.top = 0;
-  prefix(ls, &s);
-  simpleexp(ls, v);
-  while ((op = is_in(ls->token, binop)) >= 0) {
-    op += FIRSTBIN;
-    lua_pushvar(ls, v);
-    /* '^' is right associative, so must 'simulate' a higher priority */
-    pop_to(ls, &s, (op == POW)?priority[op]+1:priority[op]);
-    push(ls, &s, op);
-    next(ls);
-    prefix(ls, &s);
-    simpleexp(ls, v);
-    lua_pushvar(ls, v);
-  }
-  if (s.top > 0) {
-    lua_pushvar(ls, v);
-    pop_to(ls, &s, 0);
-  }
-}
-
-
-static void simpleexp (LexState *ls, vardesc *v) {
+static void simpleexp (LexState *ls, vardesc *v, stack_op *s) {
   check_debugline(ls);
   switch (ls->token) {
-    case '(':  /* simpleexp -> '(' exp0 ')' */
+    case NUMBER: {  /* simpleexp -> NUMBER */
+      real r = ls->seminfo.r;
       next(ls);
-      exp0(ls, v);
-      check(ls, ')');
-      break;
-
-    case NUMBER:  /* simpleexp -> NUMBER */
-      code_number(ls, ls->seminfo.r);
-      next(ls);
-      v->k = VEXP; v->info = 0;
+      /* dirty trick: check whether is a -NUMBER not followed by "^" */
+      /* (because the priority of "^" is closer than "-"...)         */
+      if (s->top > 0 && s->ops[s->top-1] == INDMINUS && ls->token != '^') {
+        s->top--;
+        r = -r;
+      }
+      code_number(ls, r);
       break;
+    }
 
     case STRING:  /* simpleexp -> STRING */
       code_string(ls, ls->seminfo.ts);  /* must use before "next" */
       next(ls);
-      v->k = VEXP; v->info = 0;
       break;
 
     case NIL:  /* simpleexp -> NIL */
       adjuststack(ls, -1);
       next(ls);
-      v->k = VEXP; v->info = 0;
       break;
 
     case '{':  /* simpleexp -> constructor */
       constructor(ls);
-      v->k = VEXP; v->info = 0;
       break;
 
     case FUNCTION: {  /* simpleexp -> FUNCTION body */
       int line = ls->linenumber;
       next(ls);
       body(ls, 0, line);
-      v->k = VEXP; v->info = 0;
       break;
     }
 
+    case '(':  /* simpleexp -> '(' exp0 ')' */
+      next(ls);
+      exp0(ls, v);
+      check(ls, ')');
+      return;
+
     case NAME: case '%':
       var_or_func(ls, v);
-      break;
+      return;
 
     default:
       luaX_error(ls, "<expression> expected");
-      break;
+      return;
+  }
+  v->k = VEXP; v->info = 0;
+}
+
+
+static void exp2 (LexState *ls, vardesc *v) {
+  stack_op s;
+  int op;
+  s.top = 0;
+  prefix(ls, &s);
+  simpleexp(ls, v, &s);
+  while ((op = is_in(ls->token, binop)) >= 0) {
+    op += FIRSTBIN;
+    lua_pushvar(ls, v);
+    /* '^' is right associative, so must 'simulate' a higher priority */
+    pop_to(ls, &s, (op == POW)?priority[op]+1:priority[op]);
+    push(ls, &s, op);
+    next(ls);
+    prefix(ls, &s);
+    simpleexp(ls, v, &s);
+    lua_pushvar(ls, v);
+  }
+  if (s.top > 0) {
+    lua_pushvar(ls, v);
+    pop_to(ls, &s, 0);
   }
 }
 
+
 static void var_or_func (LexState *ls, vardesc *v) {
   /* var_or_func -> ['%'] NAME var_or_func_tail */
   if (optional(ls, '%')) {  /* upvalue? */