mirror of
https://github.com/lua/lua
synced 2024-12-24 03:16:50 +03:00
new functions "seek" and "flush".
This commit is contained in:
Roberto Ierusalimschy
parent
cc117253c8
commit
ee22af5ced
49
liolib.c
49
liolib.c
@ -1,5 +1,5 @@
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/*
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** $Id: liolib.c,v 1.21 1998/06/18 17:04:28 roberto Exp roberto $
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** $Id: liolib.c,v 1.22 1998/08/21 17:43:44 roberto Exp roberto $
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** Standard I/O (and system) library
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** See Copyright Notice in lua.h
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*/
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@ -76,7 +76,7 @@ static int ishandler (lua_Object f)
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else return 0;
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}
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static FILE *getfile (char *name)
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static FILE *getfilebyname (char *name)
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{
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lua_Object f = lua_getglobal(name);
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if (!ishandler(f))
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@ -85,21 +85,26 @@ static FILE *getfile (char *name)
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}
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static FILE *getfileparam (char *name, int *arg)
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{
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lua_Object f = lua_getparam(*arg);
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if (ishandler(f)) {
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static FILE *getfile (int arg) {
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lua_Object f = lua_getparam(arg);
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return (ishandler(f)) ? lua_getuserdata(f) : NULL;
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}
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static FILE *getfileparam (char *name, int *arg) {
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FILE *f = getfile(*arg);
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if (f) {
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(*arg)++;
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return lua_getuserdata(f);
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return f;
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}
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else
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return getfile(name);
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return getfilebyname(name);
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}
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static void closefile (char *name)
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{
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FILE *f = getfile(name);
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FILE *f = getfilebyname(name);
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if (f == stdin || f == stdout) return;
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if (pclose(f) == -1)
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fclose(f);
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@ -271,6 +276,30 @@ static void io_write (void)
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}
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static void io_seek (void) {
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static int mode[] = {SEEK_SET, SEEK_CUR, SEEK_END};
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static char *modenames[] = {"set", "cur", "end", NULL};
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FILE *f = getfile(FIRSTARG-1+1);
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int op = luaL_findstring(luaL_opt_string(FIRSTARG-1+2, "cur"), modenames);
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long offset = luaL_opt_number(FIRSTARG-1+3, 0);
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luaL_arg_check(f, 1, "invalid file handler");
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luaL_arg_check(op != -1, 2, "invalid mode");
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op = fseek(f, offset, mode[op]);
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if (op)
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pushresult(0); /* error */
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else
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lua_pushnumber(ftell(f));
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}
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static void io_flush (void) {
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FILE *f = getfile(FIRSTARG);
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luaL_arg_check(f || lua_getparam(FIRSTARG) == LUA_NOOBJECT, 1,
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"invalid file handler");
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pushresult(fflush(f) == 0);
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}
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static void io_execute (void)
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{
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lua_pushnumber(system(luaL_check_string(1)));
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@ -420,7 +449,9 @@ static struct luaL_reg iolibtag[] = {
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{"readfrom", io_readfrom},
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{"writeto", io_writeto},
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{"appendto", io_appendto},
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{"flush", io_flush},
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{"read", io_read},
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{"seek", io_seek},
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{"write", io_write}
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};
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102
manual.tex
102
manual.tex
@ -1,4 +1,4 @@
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% $Id: manual.tex,v 1.17 1998/06/29 18:09:28 roberto Exp roberto $
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% $Id: manual.tex,v 1.18 1998/08/21 17:43:44 roberto Exp roberto $
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\documentclass[11pt]{article}
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\usepackage{fullpage,bnf}
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@ -41,7 +41,7 @@ Waldemar Celes
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\tecgraf\ --- Computer Science Department --- PUC-Rio
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}
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%\date{\small \verb$Date: 1998/06/29 18:09:28 $}
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%\date{\small \verb$Date: 1998/08/21 17:43:44 $}
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\maketitle
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@ -1879,7 +1879,7 @@ and \verb|lua_iolibopen|, declared in \verb|lualib.h|.
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\subsubsection*{\ff \T{call (func, arg [, mode [, errhandler]])}}\Deffunc{call}
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\label{pdf-call}
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This function calls function \verb|func| with
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Calls function \verb|func| with
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the arguments given by the table \verb|arg|.
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The call is equivalent to
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\begin{verbatim}
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@ -1932,7 +1932,7 @@ this limit.
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the API function \verb|lua_collectgarbage|.
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\subsubsection*{\ff \T{dofile (filename)}}\Deffunc{dofile}
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This function receives a file name,
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Receives a file name,
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opens the file, and executes the file contents as a Lua chunk,
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or as pre-compiled chunks.
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When called without arguments,
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@ -1945,7 +1945,7 @@ It issues an error when called with a non string argument.
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\verb|dofile| is equivalent to the API function \verb|lua_dofile|.
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\subsubsection*{\ff \T{dostring (string [, chunkname])}}\Deffunc{dostring}
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This function executes a given string as a Lua chunk.
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Executes a given string as a Lua chunk.
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If there is any error executing the string,
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\verb|dostring| returns \nil.
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Otherwise, it returns the values returned by the chunk,
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@ -1960,7 +1960,7 @@ Returns a new tag.
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\verb|newtag| is equivalent to the API function \verb|lua_newtag|.
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\subsubsection*{\ff \T{next (table, index)}}\Deffunc{next}
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This function allows a program to traverse all fields of a table.
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Allows a program to traverse all fields of a table.
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Its first argument is a table and its second argument
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is an index in this table.
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It returns the next index of the table and the
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@ -2038,13 +2038,13 @@ end
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\end{verbatim}
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\subsubsection*{\ff \T{tostring (e)}}\Deffunc{tostring}
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This function receives an argument of any type and
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Receives an argument of any type and
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converts it to a string in a reasonable format.
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For complete control on how numbers are converted,
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use function \verb|format|.
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\subsubsection*{\ff \T{print (e1, e2, ...)}}\Deffunc{print}
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This function receives any number of arguments,
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Receives any number of arguments,
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and prints their values using the strings returned by \verb|tostring|.
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This function is not intended for formatted output,
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but only as a quick way to show a value,
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@ -2052,14 +2052,14 @@ for instance for debugging.
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See \See{libio} for functions for formatted output.
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\subsubsection*{\ff \T{_ALERT (message)}}\Deffunc{alert}\label{alert}
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This function prints its only string argument to \IndexVerb{stderr}.
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Prints its only string argument to \IndexVerb{stderr}.
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All error messages in Lua are printed through this function.
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Therefore, a program may redefine it
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to change the way such messages are shown
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(for instance, for systems without \verb|stderr|).
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\subsubsection*{\ff \T{tonumber (e [, base])}}\Deffunc{tonumber}
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This function receives one argument,
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Receives one argument,
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and tries to convert it to a number.
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If the argument is already a number or a string convertible
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to a number, then \verb|tonumber| returns that number;
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@ -2075,7 +2075,7 @@ as well as an optional exponent part \see{coercion}.
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In other bases, only integers are accepted.
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\subsubsection*{\ff \T{type (v)}}\Deffunc{type}\label{pdf-type}
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This function allows Lua to test the type of a value.
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Allows Lua to test the type of a value.
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It receives one argument, and returns its type, coded as a string.
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The possible results of this function are
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\verb|"nil"| (a string, not the value \nil),
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@ -2086,12 +2086,12 @@ The possible results of this function are
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and \verb|"userdata"|.
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\subsubsection*{\ff \T{tag (v)}}\Deffunc{tag}
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This function allows Lua to test the tag of a value \see{TypesSec}.
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Allows Lua to test the tag of a value \see{TypesSec}.
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It receives one argument, and returns its tag (a number).
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\verb|tag| is equivalent to the API function \verb|lua_tag|.
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\subsubsection*{\ff \T{settag (t, tag)}}\Deffunc{settag}
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This function sets the tag of a given table \see{TypesSec}.
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Sets the tag of a given table \see{TypesSec}.
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\verb|tag| must be a value created with \verb|newtag|
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\see{pdf-newtag}.
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It returns the value of its first argument (the table).
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@ -2100,7 +2100,7 @@ it is impossible to change the tag of a userdata from Lua.
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\subsubsection*{\ff \T{assert (v [, message])}}\Deffunc{assert}
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This function issues an \emph{``assertion failed!''} error
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Issues an \emph{``assertion failed!''} error
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when its argument is \nil.
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This function is equivalent to the following Lua function:
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\begin{verbatim}
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@ -2113,7 +2113,7 @@ end
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\end{verbatim}
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\subsubsection*{\ff \T{error (message)}}\Deffunc{error}\label{pdf-error}
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This function calls the error handler and then terminates
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Calls the error handler and then terminates
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the last protected function called
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(in~C: \verb|lua_dofile|, \verb|lua_dostring|,
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\verb|lua_dobuffer|, or \verb|lua_callfunction|;
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@ -2136,7 +2136,7 @@ without invoking any tag method.
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and \verb|value| is any Lua value.
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\subsubsection*{\ff \T{rawsetglobal (name, value)}}\Deffunc{rawsetglobal}
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This function assigns the given value to a global variable.
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Assigns the given value to a global variable.
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The string \verb|name| does not need to be a
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syntactically valid variable name.
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Therefore,
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@ -2145,7 +2145,7 @@ this function can set global variables with strange names like
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Function \verb|rawsetglobal| returns the value of its second argument.
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\subsubsection*{\ff \T{setglobal (name, value)}}\Deffunc{setglobal}
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This function assigns the given value to a global variable,
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Assigns the given value to a global variable,
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or calls a tag method.
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Its full semantics is explained in \See{tag-method}.
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The string \verb|name| does not need to be a
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@ -2153,12 +2153,12 @@ syntactically valid variable name.
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Function \verb|setglobal| returns the value of its second argument.
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\subsubsection*{\ff \T{rawgetglobal (name)}}\Deffunc{rawgetglobal}
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This function retrieves the value of a global variable.
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Retrieves the value of a global variable.
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The string \verb|name| does not need to be a
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syntactically valid variable name.
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\subsubsection*{\ff \T{getglobal (name)}}\Deffunc{getglobal}
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This function retrieves the value of a global variable,
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Retrieves the value of a global variable,
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or calls a tag method.
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Its full semantics is explained in \See{tag-method}.
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The string \verb|name| does not need to be a
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@ -2166,19 +2166,19 @@ syntactically valid variable name.
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\subsubsection*{\ff \T{settagmethod (tag, event, newmethod)}}
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\Deffunc{settagmethod}
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This function sets a new tag method to the given pair \M{(tag, event)}.
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Sets a new tag method to the given pair \M{(tag, event)}.
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It returns the old method.
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If \verb|newmethod| is \nil,
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\verb|settagmethod| restores the default behavior for the given event.
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\subsubsection*{\ff \T{gettagmethod (tag, event)}}
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\Deffunc{gettagmethod}
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This function returns the current tag method
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Returns the current tag method
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for a given pair \M{(tag, event)}.
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\subsubsection*{\ff \T{copytagmethods (tagto, tagfrom)}}
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\Deffunc{copytagmethods}
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This function copies all tag methods from one tag to another;
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Copies all tag methods from one tag to another;
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it returns \verb|tagto|.
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@ -2190,7 +2190,7 @@ When indexing a string, the first character is at position~1
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\subsubsection*{\ff \T{strfind (str, pattern [, init [, plain]])}}
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\Deffunc{strfind}
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This function looks for the first \emph{match} of
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Looks for the first \emph{match} of
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\verb|pattern| in \verb|str|.
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If it finds one, then it returns the indices on \verb|str|
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where this occurrence starts and ends;
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@ -2265,7 +2265,7 @@ Note that numerical codes are not necessarily portable across platforms.
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\subsubsection*{\ff \T{format (formatstring, e1, e2, \ldots)}}\Deffunc{format}
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\label{format}
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This function returns a formatted version of its variable number of arguments
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Returns a formatted version of its variable number of arguments
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following the description given in its first argument (which must be a string).
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The format string follows the same rules as the \verb|printf| family of
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standard C functions.
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@ -2579,7 +2579,7 @@ usually limited and depends on the system.
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\subsubsection*{\ff \T{appendto (filename)}}\Deffunc{appendto}
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This function opens a file named \verb|filename| and sets it as the
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Opens a file named \verb|filename| and sets it as the
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value of \verb|_OUTPUT|.
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Unlike the \verb|writeto| operation,
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this function does not erase any previous content of the file.
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@ -2591,26 +2591,58 @@ available to close an output file opened by \verb|appendto|.
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\subsubsection*{\ff \T{remove (filename)}}\Deffunc{remove}
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This function deletes the file with the given name.
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Deletes the file with the given name.
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If this function fails, it returns \nil,
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plus a string describing the error.
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\subsubsection*{\ff \T{rename (name1, name2)}}\Deffunc{rename}
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This function renames file named \verb|name1| to \verb|name2|.
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Renames file named \verb|name1| to \verb|name2|.
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If this function fails, it returns \nil,
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plus a string describing the error.
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\subsubsection*{\ff \T{flush ([filehandle])}}\Deffunc{flush}
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Saves any written data to the given file.
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If \verb|filehandle| is not specified,
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flushes all open files.
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If this function fails, it returns \nil,
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plus a string describing the error.
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\subsubsection*{\ff \T{seek (filehandle [, whence] [, offset])}}\Deffunc{seek}
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Sets the file position, measured in bytes from the beginning of the file,
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to the position given by \verb|offset| plus a base
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specified by the string \verb|whence|, as follows:
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\begin{description}
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\item[\tt "set"] base is position 0 (beginning of the file);
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\item[\tt "cur"] base is current position;
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\item[\tt "end"] base is end of file;
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\end{description}
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In case of success, function \verb|seek| returns the final file position,
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measured in bytes from the beginning of the file.
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If the call fails, it returns \nil,
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plus a string describing the error.
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The default value for \verb|whence| is \verb|"cur"|,
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and for \verb|offset| is 0.
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Therefore, the call \verb|seek(file)| returns the current
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file position, without changing it;
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the call \verb|seek(file, "set")| sets the position to the
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beginning of the file (and returns 0);
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and the call \verb|seek(file, "end")| sets the position to the
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end of the file, and returns its size.
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\subsubsection*{\ff \T{tmpname ()}}\Deffunc{tmpname}
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This function returns a string with a file name that can safely
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Returns a string with a file name that can safely
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be used for a temporary file.
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The file must be explicitly removed when no longer needed.
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\subsubsection*{\ff \T{read ([filehandle] [readpattern])}}\Deffunc{read}
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This function reads the file \verb|_INPUT|,
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or from \verb|filehandle| if this argument is given,
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Reads file \verb|_INPUT|,
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or \verb|filehandle| if this argument is given,
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according to a read pattern, which specifies how much to read;
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characters are read from the input file until
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the read pattern fails or ends.
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@ -2662,9 +2694,9 @@ or \nil\ if the next characters do not conform to an integer format.
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\subsubsection*{\ff \T{write ([filehandle, ] value1, ...)}}\Deffunc{write}
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This function writes the value of each of its arguments to the
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Writes the value of each of its arguments to
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file \verb|_OUTPUT|,
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or to \verb|filehandle| if this argument is given,
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or to \verb|filehandle| if this argument is given.
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The arguments must be strings or numbers.
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To write other values,
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use \verb|tostring| or \verb|format| before \verb|write|.
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@ -2673,7 +2705,7 @@ plus a string describing the error.
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\subsubsection*{\ff \T{date ([format])}}\Deffunc{date}
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This function returns a string containing date and time
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Returns a string containing date and time
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formatted according to the given string \verb|format|,
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following the same rules of the ANSI C function \verb|strftime|.
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When called without arguments,
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@ -2682,12 +2714,12 @@ the host system and the locale.
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\subsubsection*{\ff \T{clock ()}}\Deffunc{clock}
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This function returns an approximation of the amount of CPU time
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Returns an approximation of the amount of CPU time
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used by the program, in seconds.
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\subsubsection*{\ff \T{exit ([code])}}\Deffunc{exit}
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This function calls the C function \verb|exit|,
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Calls the C function \verb|exit|,
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with an optional \verb|code|,
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to terminate the program.
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The default value for \verb|code| is 1.
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