From c454dc7bdd7f5b30bcd8a691351839b3179fe45c Mon Sep 17 00:00:00 2001
From: Roberto Ierusalimschy <roberto@inf.puc-rio.br>
Date: Thu, 11 Mar 1999 16:00:12 -0300
Subject: no more if expressions.
---
lparser.c | 31 ++++++++-----------------------
manual.tex | 15 ++-------------
2 files changed, 10 insertions(+), 36 deletions(-)
diff --git a/lparser.c b/lparser.c
index 91f585f0..8f3f7efb 100644
--- 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
index 373e0e10..3c550cd7 100644
--- 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.
--
cgit v1.2.3-55-g6feb