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"locale" support + better uniformity in formating

v5-2
Roberto Ierusalimschy 28 years ago
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  1. 97
      manual.tex

97
manual.tex
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@ -1,8 +1,7 @@
% $Id: manual.tex,v 2.8 1997/06/27 22:38:49 roberto Exp roberto $
% $Id: manual.tex,v 2.9 1997/07/01 17:41:34 roberto Exp roberto $
\documentstyle[fullpage,11pt,bnf]{article}
\newcommand{\rw}[1]{{\bf #1}}
\newcommand{\See}[1]{Section~\ref{#1}}
\newcommand{\see}[1]{(see \See{#1})}
\newcommand{\M}[1]{\emph{#1}}
@ -39,7 +38,7 @@ Waldemar Celes
\tecgraf\ --- Computer Science Department --- PUC-Rio
}
\date{\small \verb$Date: 1997/06/27 22:38:49 $}
\date{\small \verb$Date: 1997/07/01 17:41:34 $}
\maketitle
@ -167,14 +166,14 @@ Before the first assignment, the value of a global variable is \nil;
this default can be changed \see{tag-method}.
The unit of execution of Lua is called a \Def{chunk}.
The syntax%
\footnote{As usual, \rep{\emph{a}} means 0 or more \emph{a}'s,
\opt{\emph{a}} means an optional \emph{a} and \oneormore{\emph{a}} means
one or more \emph{a}'s.}
for chunks is:
The syntax for chunks is:
\begin{Produc}
\produc{chunk}{\rep{stat \Or function} \opt{ret}}
\end{Produc}%
(As usual, \rep{\emph{a}} means 0 or more \emph{a}'s,
\opt{\emph{a}} means an optional \emph{a} and \oneormore{\emph{a}} means
one or more \emph{a}'s.)
A chunk may contain statements and function definitions,
and may be in a file or in a string inside the host program.
A chunk may optionally end with a \verb|return| statement \see{return}.
@ -182,10 +181,10 @@ When a chunk is executed, first all its functions and statements are compiled,
then the statements are executed in sequential order.
All modifications a chunk effects on the global environment persist
after its end.
Those include modifications to global variables and definitions
of new functions%
\footnote{Actually, a function definition is an
assignment to a global variable \see{TypesSec}.}.
Those include modifications to global variables
and definitions of new functions
(actually, a function definition is an
assignment to a global variable \see{TypesSec}).
Chunks may be pre-compiled into binary form;
see program \IndexVerb{luac} for details.
@ -207,7 +206,9 @@ There are six \Index{basic types} in Lua: \Def{nil}, \Def{number},
\emph{Nil} is the type of the value \nil,
whose main property is to be different from any other value.
\emph{Number} represents real (floating-point) numbers,
while \emph{string} has the usual meaning.
while \emph{string} has the usual meaning;
notice that Lua is \Index{eight-bit clean},
so strings can have ISO characters.
The function \verb|type| returns a string describing the type
of a given value \see{pdf-type}.
@ -275,9 +276,11 @@ This section describes the lexis, the syntax and the semantics of Lua.
\subsection{Lexical Conventions} \label{lexical}
Lua is a case-sensitive language.
\Index{Identifiers} can be any string of letters, digits, and underscores,
not beginning with a digit.
The definition of letter depends on the current locale:
Any character considered alphabetic by the current locale
can be used in an identifier.
The following words are reserved, and cannot be used as identifiers:
\index{reserved words}
\begin{verbatim}
@ -286,6 +289,9 @@ The following words are reserved, and cannot be used as identifiers:
nil not or repeat
return then until while
\end{verbatim}
Lua is a case-sensitive language:
\T{and} is a reserved word, but \T{And} and \T{\'and}
(if the locale permits) are two other different identifiers.
The following strings denote other \Index{tokens}:
\begin{verbatim}
@ -307,9 +313,9 @@ other quoted strings.
\Index{Comments} start anywhere outside a string with a
double hyphen (\verb|--|) and run until the end of the line.
Moreover,
the first line of a chunk file is skipped if it starts with \verb|#|%
\footnote{This facility allows the use of Lua as a script interpreter
in Unix systems \see{lua-sa}.}.
the first line of a chunk file is skipped if it starts with \verb|#|.
This facility allows the use of Lua as a script interpreter
in Unix systems \see{lua-sa}.
\Index{Numerical constants} may be written with an optional decimal part,
and an optional decimal exponent.
@ -325,9 +331,9 @@ The \verb|$| can be followed by any of the following directives:
\begin{description}
\item[\T{debug}] --- turn on some debugging facilities \see{pragma}.
\item[\T{nodebug}] --- turn off some debugging facilities \see{pragma}.
\item[{\tt if \M{cond}}] --- starts a conditional part.
\item[\T{if \M{cond}}] --- starts a conditional part.
If \M{cond} is false, then this part is skipped by the lexical analyzer.
\item[{\tt ifnot \M{cond}}] --- starts a conditional part.
\item[\T{ifnot \M{cond}}] --- starts a conditional part.
If \M{cond} is true, then this part is skipped by the lexical analyzer.
\item[\T{end}] --- ends a conditional part.
\item[\T{else}] --- starts an ``else'' conditional part,
@ -439,9 +445,9 @@ an assignment \verb|x = val|, where \verb|x| is a global variable,
is equivalent to a call \verb|setglobal('x', val)|;
an assignment \verb|t[i] = val| is equivalent to
\verb|settable_event(t, i, val)|.
See \See{tag-method} for a description of these functions%
\footnote{Function \verb|setglobal| is pre-defined in Lua.
Function \T{settable\_event} is used only for explanatory purposes.}.
See \See{tag-method} for a description of these functions.
(Function \verb|setglobal| is pre-defined in Lua.
Function \T{settable\_event} is used only for explanatory purposes.)
The syntax \verb|var.NAME| is just syntactic sugar for
\verb|var["NAME"]|:
@ -515,9 +521,9 @@ An access to a global variable \verb|x| is equivalent to a
call \verb|getglobal('x')|;
an access to an indexed variable \verb|t[i]| is equivalent to
a call \verb|gettable_event(t, i)|.
See \See{tag-method} for a description of these functions%
\footnote{Function \verb|getglobal| is pre-defined in Lua.
Function \T{gettable\_event} is used only for explanatory purposes.}.
See \See{tag-method} for a description of these functions.
(Function \verb|getglobal| is pre-defined in Lua.
Function \T{gettable\_event} is used only for explanatory purposes.)
The non-terminal \M{exp1} is used to indicate that the values
returned by an expression must be adjusted to one single value:
@ -563,9 +569,6 @@ If both arguments are numbers, then they are compared as such.
Otherwise, if both arguments are strings,
their values are compared using lexicographical order.
Otherwise, the ``order'' tag method is called \see{tag-method}.
%Note that the conversion rules of Section~\ref{coercion}
%do apply to order operators.
%Thus, \verb|"2">"12"| evaluates to true.
\subsubsection{Logical Operators}
Like control structures, all logical operators
@ -643,7 +646,7 @@ is essentially equivalent to:
The form \emph{ffieldlist1} initializes other fields in a table:
\begin{Produc}
\produc{ffieldlist1}{ffield \rep{\ter{,} ffield} \opt{\ter{,}}}
\produc{ffield}{\ter{[} exp \ter{]} \ter {=} exp \Or name \ter{=} exp}
\produc{ffield}{\ter{[} exp \ter{]} \ter{=} exp \Or name \ter{=} exp}
\end{Produc}%
For example:
\begin{verbatim}
@ -1322,7 +1325,7 @@ The use of explicit nested blocks is strongly encouraged.
\subsection{Executing Lua Code}
A host program can execute Lua chunks written in a file or in a string
using the following functions:%
using the following functions:
\Deffunc{lua_dofile}\Deffunc{lua_dostring}
\begin{verbatim}
int lua_dofile (char *filename);
@ -1967,7 +1970,7 @@ The following combinations are allowed in describing a character class:
\item[\T{\%U}] --- represents all non upper case letter characters.
\item[\T{\%w}] --- represents all alphanumeric characters.
\item[\T{\%W}] --- represents all non alphanumeric characters.
\item[{\tt \%\M{x}}] (where \M{x} is any non alphanumeric character) ---
\item[\T{\%\M{x}}] (where \M{x} is any non alphanumeric character) ---
represents the character \M{x}.
This is the standard way to escape the magic characters \verb|()%.[*-?|.
\item[\T{[char-set]}] ---
@ -1976,17 +1979,21 @@ characters in char-set.
To include a \verb|]| in char-set, it must be the first character.
A range of characters may be specified by
separating the end characters of the range with a \verb|-|;
e.g., \verb|A-Z| specifies the upper case characters.
e.g., \verb|A-Z| specifies the English upper case characters.
If \verb|-| appears as the first or last character of char-set,
then it represents itself.
All classes \verb|%|\emph{x} described above can also be used as
components in a char-set.
All other characters in char-set represent themselves.
\item[{\tt [\^{ }char-set]}] ---
\item[\T{[\^{ }char-set]}] ---
represents the complement of char-set,
where char-set is interpreted as above.
\end{description}
The definitions of letter, space, etc depend on the current locale.
In particular, the class \verb|[a-z]| may not be equivalent to \verb|%l|.
The second form should be preferred for more portable programs.
\paragraph{Pattern Item:}
a \Def{pattern item} may be:
\begin{itemize}
@ -2006,11 +2013,11 @@ these repetition items will always match the shortest possible sequence.
a single character class followed by \verb|?|,
which matches 0 or 1 occurrence of a character in the class;
\item
{\tt \%\M{n}}, for \M{n} between 1 and 9;
\T{\%\M{n}}, for \M{n} between 1 and 9;
such item matches a sub-string equal to the n-th captured string
(see below);
\item
{\tt \%b\M{xy}}, where \M{x} and \M{y} are two distinct characters;
\T{\%b\M{xy}}, where \M{x} and \M{y} are two distinct characters;
such item matches strings that start with \M{x}, end with \M{y},
and where the \M{x} and \M{y} are \emph{balanced}.
That means that, if one reads the string from left to write,
@ -2039,6 +2046,7 @@ stored as the first capture (and therefore has number 1);
the character matching \verb|.| is captured with number 2,
and the part matching \verb|%s*| has number 3.
\subsection{Mathematical Functions} \label{mathlib}
This library is an interface to some functions of the standard C math library.
@ -2101,8 +2109,6 @@ When called with a file name, it opens the named file,
sets its handle as the value of \verb|_INPUT|,
and returns this value.
It does not close the current input file.
%When called with a file handle returned by a previous call,
%it simply assigns it to \verb|_INPUT|.
When called without parameters,
it closes the \verb|_INPUT| file,
and restores \verb|stdin| as the value of \verb|_INPUT|.
@ -2130,8 +2136,6 @@ and returns this value.
It does not close the current output file.
Notice that, if the file already exists,
then it will be \emph{completely erased} with this operation.
%When called with a file handle returned by a previous call,
%it restores the file as the current output.
When called without parameters,
this function closes the \verb|_OUTPUT| file,
and restores \verb|stdout| as the value of \verb|_OUTPUT|.
@ -2203,15 +2207,13 @@ from the input if it belongs to the class;
it never fails.
A character class followed by \verb|*| reads until a character that
does not belong to the class, or end of file;
since it can match a sequence of zero characters, it never fails.%
\footnote{
since it can match a sequence of zero characters, it never fails.
Notice that the behavior of read patterns is different from
the regular pattern matching behavior,
where a \verb|*| expands to the maximum length \emph{such that}
the rest of the pattern does not fail.
With the read pattern behavior
there is no need for backtracking the reading.
}
A pattern item may contain sub-patterns enclosed in curly brackets,
that describe \Def{skips}.
@ -2270,6 +2272,17 @@ This function is equivalent to the C function \verb|system|.
It passes \verb|command| to be executed by an operating system shell.
It returns an error code, which is system-dependent.
\subsubsection*{\ff \T{setlocale (locale [, category])}}\Deffunc{setlocale}
This function is an interface to the ANSI C function \verb|setlocale|.
\verb|locale| is a string specifing a locale;
\verb|category| is a number describing which category to change:
0 is \verb|LC_ALL|, 1 is \verb|LC_COLLATE|, 2 is \verb|LC_CTYPE|,
3 is \verb|LC_MONETARY|, 4 is \verb|LC_NUMERIC|, and 5 is \verb|LC_TIME|;
the default category is \verb|LC_ALL|.
The function returns the name of the new locale,
or \nil\ if the request cannot be honored.
\section{The Debugger Interface} \label{debugI}

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