Local attributes can be used in list of local variables

The syntax for local attributes ('const'/'toclose') was unified with the regular syntax for local variables, so that we can have variables with attributes in local definitions with multiple names; for instance: local <toclose> f, <const> err = io.open(fname) This new syntax does not implement constant propagation, yet. This commit also has some small improvements to the manual.
author: Roberto Ierusalimschy <roberto@inf.puc-rio.br> 2019-07-03 14:18:07 -0300
committer: Roberto Ierusalimschy <roberto@inf.puc-rio.br> 2019-07-03 14:18:07 -0300
commit: 4d46289331395a845c5de1f6c0e0fe873c50db4f (patch)
tree: 96649174d3c13830549ad026af0133e0b789d411 /manual
parent: 8eca21c2e85625390a2a3b08c231e75e315980b0 (diff)
download: lua-4d46289331395a845c5de1f6c0e0fe873c50db4f.tar.gz
lua-4d46289331395a845c5de1f6c0e0fe873c50db4f.tar.bz2
lua-4d46289331395a845c5de1f6c0e0fe873c50db4f.zip
1 files changed, 34 insertions, 26 deletions
diff --git a/manual/manual.of b/manual/manual.of
index e9416956..136e9022 100644
--- a/manual/manual.of
+++ b/manual/manual.of
@@ -1399,23 +1399,30 @@ they must all result in numbers.
 Their values are called respectively
 the @emph{initial value}, the @emph{limit}, and the @emph{step}.
 If the step is absent, it defaults @N{to 1}.
-Then the loop body is repeated with the value of the control variable
+If both the initial value and the step are integers,
+the loop is done with integers;
+note that the limit may not be an integer.
+Otherwise, the loop is done with floats.
+(Beware of floating-point accuracy in this case.)
+After that initialization,
+the loop body is repeated with the value of the control variable
 going through an arithmetic progression,
 starting at the initial value,
-with a common difference given by the step,
+with a common difference given by the step.
-until that value passes the limit.
 A negative step makes a decreasing sequence;
 a step equal to zero raises an error.
+The loop continues while the value is less than
+or equal to the limit
+(greater than or equal to for a negative step).
 If the initial value is already greater than the limit
 (or less than, if the step is negative),
 the body is not executed.
-If both the initial value and the step are integers,
+For integer loops,
-the loop is done with integers;
+the control variable never wraps around;
-in this case, the range of the control variable is clipped
+instead, the loop ends in case of an overflow.
-by the range of integers.
-Otherwise, the loop is done with floats.
-(Beware of floating-point accuracy in this case.)
 You should not change the value of the control variable
 during the loop.
@@ -1490,22 +1497,25 @@ Function calls are explained in @See{functioncall}.
 @x{Local variables} can be declared anywhere inside a block.
 The declaration can include an initialization:
 @Produc{
-@producname{stat}@producbody{@Rw{local} namelist @bnfopt{@bnfter{=} explist}}
+@producname{stat}@producbody{@Rw{local} attnamelist @bnfopt{@bnfter{=} explist}}
-@producname{stat}@producbody{
+@producname{attnamelist}@producbody{
-    @Rw{local} @bnfter{<} Name @bnfter{>} Name @bnfter{=} exp
+  attrib @bnfNter{Name} @bnfrep{@bnfter{,} attrib @bnfNter{Name}}}
-}}
+}
 If present, an initial assignment has the same semantics
 of a multiple assignment @see{assignment}.
 Otherwise, all variables are initialized with @nil.
-The second syntax declares a local with a given attribute,
-which is the name between the angle brackets.
+Each variable name may be preceded by an attribute
-In this case, there must be an initialization.
+(a name between angle brackets):
+@Produc{
+@producname{attrib}@producbody{@bnfopt{@bnfter{<} @bnfNter{Name} @bnfter{>}}}
+}
 There are two possible attributes:
 @id{const}, which declares a @x{constant variable},
 that is, a variable that cannot be assigned to
 after its initialization;
 and @id{toclose}, which declares a to-be-closed variable @see{to-be-closed}.
+A list of variables can contain at most one to-be-closed variable.
 A chunk is also a block @see{chunks},
 and so local variables can be declared in a chunk outside any explicit block.
@@ -1516,12 +1526,6 @@ The visibility rules for local variables are explained in @See{visibility}.
 @sect3{to-be-closed| @title{To-be-closed Variables}
-A local variable can be declared as a @def{to-be-closed} variable,
-using the identifier @id{toclose} as its attribute:
-@Produc{
-@producname{stat}@producbody{
-  @Rw{local} @bnfter{<} @id{toclose} @bnfter{>} Name @bnfter{=} exp
-}}
 A to-be-closed variable behaves like a constant local variable,
 except that its value is @emph{closed} whenever the variable
 goes out of scope, including normal block termination,
@@ -8215,7 +8219,7 @@ then @id{date} returns the date as a string,
 formatted according to the same rules as the @ANSI{strftime}.
 If @id{format} is absent, it defaults to @St{%c},
-which gives a reasonable date and time representation
+which gives a human-readable date and time representation
 using the current locale.
 On non-POSIX systems,
@@ -9022,10 +9026,14 @@ and @bnfNter{LiteralString}, see @See{lexical}.)
 @OrNL   @Rw{for} namelist @Rw{in} explist @Rw{do} block @Rw{end}
 @OrNL   @Rw{function} funcname funcbody
 @OrNL   @Rw{local} @Rw{function} @bnfNter{Name} funcbody
-@OrNL   @Rw{local} namelist @bnfopt{@bnfter{=} explist}
+@OrNL   @Rw{local} attnamelist @bnfopt{@bnfter{=} explist}
-@OrNL   @Rw{local} @bnfter{<} Name @bnfter{>} Name @bnfter{=} exp
 }
+@producname{attnamelist}@producbody{
+  attrib @bnfNter{Name} @bnfrep{@bnfter{,} attrib @bnfNter{Name}}}
+@producname{attrib}@producbody{@bnfopt{@bnfter{<} @bnfNter{Name} @bnfter{>}}}
 @producname{retstat}@producbody{@Rw{return}
                                   @bnfopt{explist} @bnfopt{@bnfter{;}}}
author	Roberto Ierusalimschy <roberto@inf.puc-rio.br>	2019-07-03 14:18:07 -0300
committer	Roberto Ierusalimschy <roberto@inf.puc-rio.br>	2019-07-03 14:18:07 -0300
commit	4d46289331395a845c5de1f6c0e0fe873c50db4f (patch)
tree	96649174d3c13830549ad026af0133e0b789d411 /manual
parent	8eca21c2e85625390a2a3b08c231e75e315980b0 (diff)
download	lua-4d46289331395a845c5de1f6c0e0fe873c50db4f.tar.gz lua-4d46289331395a845c5de1f6c0e0fe873c50db4f.tar.bz2 lua-4d46289331395a845c5de1f6c0e0fe873c50db4f.zip

diff --git a/manual/manual.of b/manual/manual.of index e9416956..136e9022 100644 --- a/manual/manual.of +++ b/manual/manual.of
@@ -1399,23 +1399,30 @@ they must all result in numbers.
1399	Their values are called respectively	1399	Their values are called respectively
1400	the @emph{initial value}, the @emph{limit}, and the @emph{step}.	1400	the @emph{initial value}, the @emph{limit}, and the @emph{step}.
1401	If the step is absent, it defaults @N{to 1}.	1401	If the step is absent, it defaults @N{to 1}.
1402	Then the loop body is repeated with the value of the control variable	1402
		1403	If both the initial value and the step are integers,
		1404	the loop is done with integers;
		1405	note that the limit may not be an integer.
		1406	Otherwise, the loop is done with floats.
		1407	(Beware of floating-point accuracy in this case.)
		1408
		1409	After that initialization,
		1410	the loop body is repeated with the value of the control variable
1403	going through an arithmetic progression,	1411	going through an arithmetic progression,
1404	starting at the initial value,	1412	starting at the initial value,
1405	with a common difference given by the step,	1413	with a common difference given by the step.
1406	until that value passes the limit.
1407	A negative step makes a decreasing sequence;	1414	A negative step makes a decreasing sequence;
1408	a step equal to zero raises an error.	1415	a step equal to zero raises an error.
		1416	The loop continues while the value is less than
		1417	or equal to the limit
		1418	(greater than or equal to for a negative step).
1409	If the initial value is already greater than the limit	1419	If the initial value is already greater than the limit
1410	(or less than, if the step is negative),	1420	(or less than, if the step is negative),
1411	the body is not executed.	1421	the body is not executed.
1412		1422
1413	If both the initial value and the step are integers,	1423	For integer loops,
1414	the loop is done with integers;	1424	the control variable never wraps around;
1415	in this case, the range of the control variable is clipped	1425	instead, the loop ends in case of an overflow.
1416	by the range of integers.
1417	Otherwise, the loop is done with floats.
1418	(Beware of floating-point accuracy in this case.)
1419		1426
1420	You should not change the value of the control variable	1427	You should not change the value of the control variable
1421	during the loop.	1428	during the loop.
@@ -1490,22 +1497,25 @@ Function calls are explained in @See{functioncall}.
1490	@x{Local variables} can be declared anywhere inside a block.	1497	@x{Local variables} can be declared anywhere inside a block.
1491	The declaration can include an initialization:	1498	The declaration can include an initialization:
1492	@Produc{	1499	@Produc{
1493	@producname{stat}@producbody{@Rw{local} namelist @bnfopt{@bnfter{=} explist}}	1500	@producname{stat}@producbody{@Rw{local} attnamelist @bnfopt{@bnfter{=} explist}}
1494	@producname{stat}@producbody{	1501	@producname{attnamelist}@producbody{
1495	@Rw{local} @bnfter{<} Name @bnfter{>} Name @bnfter{=} exp	1502	attrib @bnfNter{Name} @bnfrep{@bnfter{,} attrib @bnfNter{Name}}}
1496	}}	1503	}
1497	If present, an initial assignment has the same semantics	1504	If present, an initial assignment has the same semantics
1498	of a multiple assignment @see{assignment}.	1505	of a multiple assignment @see{assignment}.
1499	Otherwise, all variables are initialized with @nil.	1506	Otherwise, all variables are initialized with @nil.
1500	The second syntax declares a local with a given attribute,	1507
1501	which is the name between the angle brackets.	1508	Each variable name may be preceded by an attribute
1502	In this case, there must be an initialization.	1509	(a name between angle brackets):
		1510	@Produc{
		1511	@producname{attrib}@producbody{@bnfopt{@bnfter{<} @bnfNter{Name} @bnfter{>}}}
		1512	}
1503	There are two possible attributes:	1513	There are two possible attributes:
1504	@id{const}, which declares a @x{constant variable},	1514	@id{const}, which declares a @x{constant variable},
1505	that is, a variable that cannot be assigned to	1515	that is, a variable that cannot be assigned to
1506	after its initialization;	1516	after its initialization;
1507	and @id{toclose}, which declares a to-be-closed variable @see{to-be-closed}.	1517	and @id{toclose}, which declares a to-be-closed variable @see{to-be-closed}.
1508		1518	A list of variables can contain at most one to-be-closed variable.
1509		1519
1510	A chunk is also a block @see{chunks},	1520	A chunk is also a block @see{chunks},
1511	and so local variables can be declared in a chunk outside any explicit block.	1521	and so local variables can be declared in a chunk outside any explicit block.
@@ -1516,12 +1526,6 @@ The visibility rules for local variables are explained in @See{visibility}.
1516		1526
1517	@sect3{to-be-closed\| @title{To-be-closed Variables}	1527	@sect3{to-be-closed\| @title{To-be-closed Variables}
1518		1528
1519	A local variable can be declared as a @def{to-be-closed} variable,
1520	using the identifier @id{toclose} as its attribute:
1521	@Produc{
1522	@producname{stat}@producbody{
1523	@Rw{local} @bnfter{<} @id{toclose} @bnfter{>} Name @bnfter{=} exp
1524	}}
1525	A to-be-closed variable behaves like a constant local variable,	1529	A to-be-closed variable behaves like a constant local variable,
1526	except that its value is @emph{closed} whenever the variable	1530	except that its value is @emph{closed} whenever the variable
1527	goes out of scope, including normal block termination,	1531	goes out of scope, including normal block termination,
@@ -8215,7 +8219,7 @@ then @id{date} returns the date as a string,
8215	formatted according to the same rules as the @ANSI{strftime}.	8219	formatted according to the same rules as the @ANSI{strftime}.
8216		8220
8217	If @id{format} is absent, it defaults to @St{%c},	8221	If @id{format} is absent, it defaults to @St{%c},
8218	which gives a reasonable date and time representation	8222	which gives a human-readable date and time representation
8219	using the current locale.	8223	using the current locale.
8220		8224
8221	On non-POSIX systems,	8225	On non-POSIX systems,
@@ -9022,10 +9026,14 @@ and @bnfNter{LiteralString}, see @See{lexical}.)
9022	@OrNL @Rw{for} namelist @Rw{in} explist @Rw{do} block @Rw{end}	9026	@OrNL @Rw{for} namelist @Rw{in} explist @Rw{do} block @Rw{end}
9023	@OrNL @Rw{function} funcname funcbody	9027	@OrNL @Rw{function} funcname funcbody
9024	@OrNL @Rw{local} @Rw{function} @bnfNter{Name} funcbody	9028	@OrNL @Rw{local} @Rw{function} @bnfNter{Name} funcbody
9025	@OrNL @Rw{local} namelist @bnfopt{@bnfter{=} explist}	9029	@OrNL @Rw{local} attnamelist @bnfopt{@bnfter{=} explist}
9026	@OrNL @Rw{local} @bnfter{<} Name @bnfter{>} Name @bnfter{=} exp
9027	}	9030	}
9028		9031
		9032	@producname{attnamelist}@producbody{
		9033	attrib @bnfNter{Name} @bnfrep{@bnfter{,} attrib @bnfNter{Name}}}
		9034
		9035	@producname{attrib}@producbody{@bnfopt{@bnfter{<} @bnfNter{Name} @bnfter{>}}}
		9036
9029	@producname{retstat}@producbody{@Rw{return}	9037	@producname{retstat}@producbody{@Rw{return}
9030	@bnfopt{explist} @bnfopt{@bnfter{;}}}	9038	@bnfopt{explist} @bnfopt{@bnfter{;}}}
9031		9039