lua

commit c454dc7bdd7f5b30bcd8a691351839b3179fe45c
parent 82ad0d57705dd3be41081118781762b72e334f1b
Author: Roberto Ierusalimschy <roberto@inf.puc-rio.br>
Date:   Thu, 11 Mar 1999 15:59:50 -0300

no more if expressions.

Diffstat:
M
lparser.c
 | 
31
++++++++-----------------------
M
manual.tex
 | 
15
++-------------

2 files changed, 10 insertions(+), 36 deletions(-)
diff --git a/lparser.c b/lparser.c
@@ -1,5 +1,5 @@
 /*
-** $Id: lparser.c,v 1.27 1999/03/05 21:16:07 roberto Exp roberto $
+** $Id: lparser.c,v 1.28 1999/03/10 14:09:45 roberto Exp roberto $
 ** LL(1) Parser and code generator for Lua
 ** See Copyright Notice in lua.h
 */
@@ -118,7 +118,7 @@ static void exp1 (LexState *ls);
 static void exp2 (LexState *ls, vardesc *v);
 static void explist (LexState *ls, listdesc *e);
 static void explist1 (LexState *ls, listdesc *e);
-static void ifpart (LexState *ls, int isexp, int line);
+static void ifpart (LexState *ls, int line);
 static void parlist (LexState *ls);
 static void part (LexState *ls, constdesc *cd);
 static void recfield (LexState *ls);
@@ -684,7 +684,7 @@ static int stat (LexState *ls) {
   FuncState *fs = ls->fs;
   switch (ls->token) {
     case IF:  /* stat -> IF ifpart END */
-      ifpart(ls, 0, line);
+      ifpart(ls, line);
       return 1;
 
     case WHILE: {  /* stat -> WHILE cond DO block END */
@@ -833,31 +833,20 @@ static void body (LexState *ls, int needself, int line) {
 }
 
 
-static void ifpart (LexState *ls, int isexp, int line) {
+static void ifpart (LexState *ls, int line) {
   /* ifpart -> cond THEN block [ELSE block | ELSEIF ifpart] */
-  /* ifpart -> cond THEN exp [ELSE exp | ELSEIF ifpart] */
   int c;
   int e;
   next(ls);  /* skip IF or ELSEIF */
   c = cond(ls);
   check(ls, THEN);
-  if (isexp) {
-    exp1(ls);
-    deltastack(ls, -1);  /* only 'then' x-or 'else' will stay on the stack */
-  }
-  else block(ls);
+  block(ls);
   e = SaveWord(ls);
   if (ls->token == ELSEIF)
-    ifpart(ls, isexp, line);
+    ifpart(ls, line);
   else {
-    int elsepart = optional(ls, ELSE);
-    if (!isexp) {
-      if (elsepart) block(ls);
-    }
-    else {  /* is exp */
-      if (elsepart) exp1(ls);
-      else adjuststack(ls, -1);  /* empty else exp -> push nil */
-    }
+    if (optional(ls, ELSE))
+      block(ls);
     check_match(ls, END, IF, line);
   }
   codeIf(ls, c, e);
@@ -991,10 +980,6 @@ static void simpleexp (LexState *ls, vardesc *v, stack_op *s) {
       body(ls, 0, ls->linenumber);
       break;
 
-    case IF:  /* simpleexp -> IF ifpart END */
-      ifpart(ls, 1, ls->linenumber);
-      break;
-
     case '(':  /* simpleexp -> '(' exp0 ')' */
       next(ls);
       exp0(ls, v);
diff --git a/manual.tex b/manual.tex
@@ -1,4 +1,4 @@
-% $Id: manual.tex,v 1.25 1999/03/04 21:23:39 roberto Exp roberto $
+% $Id: manual.tex,v 1.26 1999/03/10 14:09:45 roberto Exp roberto $
 
 \documentclass[11pt]{article}
 \usepackage{fullpage,bnf}
@@ -41,7 +41,7 @@ Waldemar Celes
 \tecgraf\ --- Computer Science Department --- PUC-Rio
 }
 
-%\date{\small \verb$Date: 1999/03/04 21:23:39 $}
+%\date{\small \verb$Date: 1999/03/10 14:09:45 $}
 
 \maketitle
 
@@ -686,17 +686,6 @@ All binary operators are left associative,
 except for \verb|^| (exponentiation),
 which is right associative.
 
-\subsubsection{If Expressions}
-\begin{Produc}
-\produc{exp}{\rwd{if} exp1 \rwd{then} exp1
-   \rep{\rwd{elseif} exp1 \rwd{then} exp1}
-   \opt{\rwd{else} exp1} \rwd{end}}
-\end{Produc}%
-An \Index{if expression} chooses an expression to evaluate
-according to its condition.
-Its final value is the value of the chosen expression.
-An absent else-part is equivalent to \verb|else nil|.
-
 \subsubsection{Table Constructors} \label{tableconstructor}
 Table \Index{constructors} are expressions that create tables;
 every time a constructor is evaluated, a new table is created.