commit 84df3ac2675af018d85d26746165325475575965
parent 55a70c9719cce1b5b9ba78919a0ab54c8442af73
Author: Roberto Ierusalimschy <roberto@inf.puc-rio.br>
Date: Mon, 29 Jan 1996 15:08:03 -0200
new functions "tostring", "assert", and "format".
Diffstat:
| M | manual.tex | | | 57 | ++++++++++++++++++++++++++++++++++++++++++++++++++------- |
1 file changed, 50 insertions(+), 7 deletions(-)
diff --git a/manual.tex b/manual.tex
@@ -1,3 +1,5 @@
+% $Id: $
+
\documentstyle[A4,11pt,bnf]{article}
\newcommand{\rw}[1]{{\bf #1}}
@@ -42,6 +44,8 @@ as a configuration language for any program that needs one.
This document describes version 2.2 of the Lua programming language and the
API that allows interaction between Lua programs and its host C program.
It also presents some examples of using the main features of the system.
+
+{\em Lua manual: \verb$Date$, \verb$Revision$}
\end{abstract}
\vspace{4ex}
@@ -1080,8 +1084,9 @@ it can be unlocked with a call to \verb'lua_unlock'.
The set of \Index{predefined functions} in Lua is small but powerful.
Most of them provide features that allows some degree of
\Index{reflexivity} in the language.
-Many of these features cannot be simulated with the rest of the
-Language nor with the standard API.
+Some of these features cannot be simulated with the rest of the
+Language nor with the standard Lua API.
+Others are just helpful interfaces to common API functions.
The libraries, on the other hand, provide useful routines
that are implemented directly through the standard API.
@@ -1104,7 +1109,10 @@ declared in \verb-lualib.h-.
\subsubsection*{{\tt dofile (filename)}}\Deffunc{dofile}
This function receives a file name,
opens it and executes its contents as a Lua chunk.
+When called without arguments,
+it executes the contents of the standard input.
It returns 1 if there are no errors, \nil\ otherwise.
+It issues an error when called with a non string argument.
\subsubsection*{{\tt dostring (string)}}\Deffunc{dostring}
This function executes a given string as a Lua chunk.
@@ -1141,6 +1149,10 @@ and its value,
or \nil\ if there are no more variables.
See Section \ref{exnext} for an example of the use of this function.
+\subsubsection*{{\tt tostring (e)}}\Deffunc{tostring}
+This function receives an argument of any type and
+converts it to a string in a reasonable format.
+
\subsubsection*{{\tt print (e1, e2, ...)}}\Deffunc{print}
This function receives any number of arguments,
and prints their values in a reasonable format.
@@ -1174,6 +1186,10 @@ This tag can be used to distinguish between user
data with different tags,
and between C functions and Lua functions.
+\subsubsection*{{\tt assert (v)}}\Deffunc{assert}
+This function issues an {\em ``assertion failed!''} error
+when its argument is \nil.
+
\subsubsection*{{\tt error (message)}}\Deffunc{error}
This function issues an error message and terminates
the last called function from the library
@@ -1185,6 +1201,7 @@ This function assigns the given value to a global variable.
The string \verb'name' does not need to be a syntactically valid variable name.
Therefore, this function can set global variables with strange names like
\verb'm v 1' or \verb'34'.
+It returns the value of its second argument.
\subsubsection*{{\tt getglobal (name)}}\Deffunc{getglobal}
This function retrieves the value of a global variable.
@@ -1240,11 +1257,19 @@ All other characters are left unchanged.
Returns the ascii code of the character \verb's[i]'.
If \verb'i' is absent, it is assumed to be 1.
-\subsubsection*{{\tt int2str (\{i\})}}\Deffunc{int2str}
-Receives 0 or more numbers.
-Returns a string with length equal to the number of arguments,
-wherein each character has ascii value equal
-to its correspondent argument.
+\subsubsection*{{\tt format (formatstring, e1, e2, \ldots)}}\Deffunc{format}
+This function returns a formated version of its variable number of arguments
+following the description given in its first argument (which must be a string).
+The format string follows the same rules as the \verb'printf' family of
+standard C functions.
+The only differencies are that the options/modifiers
+ \verb'*', \verb'l', \verb'L', \verb'n', \verb'p',
+ and \verb'h' are not supported.
+The options \verb'c', \verb'd', \verb'i', \verb'o', \verb'u',
+\verb'x', \verb'X', \verb'e', \verb'E', \verb'f', and \verb'g' all
+expect a number argument,
+while \verb's' expects a string.
+
\subsection{Mathematical Functions} \label{mathlib}
@@ -1350,6 +1375,8 @@ Particularly, the format \verb'"s1"' reads a single character.
\subsubsection*{{\tt readuntil (char)}}\Deffunc{readuntil}
Reads the current input until the first ocurrence of the given character.
+When called with no parameters or with nil,
+reads until the end of the current input file.
Returns the string read.
The character itself is not read.
@@ -1383,10 +1410,26 @@ For integers, it is the minimum number of digits.
This option has no meaning for strings.
\end{description}
+{\em Warning:}
+This format parameter is now obsolete;
+formated output should use the \verb'format' function.
+
When called without a format string,
this function writes numbers using the \verb'%g' format
and strings with \verb'%s'.
+\subsubsection*{{\tt date ()}}\Deffunc{date}
+
+This function returns 4 values:
+the current day of the month,
+the month ([1-12]), the current year,
+and the day of the week (1 = Sunday, 7 = Saturday).
+
+\subsubsection*{{\tt time ()}}\Deffunc{time}
+
+This function returns the current time through 3 values:
+hours ([0-23]), minutes, and seconds.
+
% \subsubsection*{{\tt debug ()}}
% This function, when called, repeatedly presents a prompt \verb'lua_debug> '
% in the error output stream (\verb'stderr'),
