aer(5)

NAME

aer - aegis report script language definition

DESCRIPTION

This manual entry describes the report generator script language used by the aer(1) command. The language resembles C, with a touch of awk and perl for flavour. It also closely resembles the appearance of aegis' database files.

This language grew out of the need to have a general purpose programming language to describe reports, and yet be as familiar as possible to the people who will be using it.

WORDS AND SYMBOLS

This section describes the various words and symbols understood by the language.
Names: A name is a contiguous set of alphanumeric characters, including
underscore (_). It must not start with a digit. Names may be of any length. Names are case sensitive, so uppercase and lowercase letters are unique.; Here are some examples of names

+-----------------------------+
| print sqrt if |
|how_long UpperCase dig57 |
+-----------------------------+; Some words are reserved as keywords. These are the words which appear in bold in the statement descriptions, below.
Integer Constants: An integer constant may be decimal, any sequence of digits. Constants may be octal, any sequence of octal digits starting with a zero. Constant may be hexadecimal, any sequence of hexadecimal digits, starting with a 0x prefix. These are represented by the internal long type, so significance is limited.; Here are some examples of integer constants:

+---------------------------------------+
| 43 015 0xbeEf |
|2147483647 017777777777 0x7FFFFFFF |
+---------------------------------------+; Floating Point Constants
A floating point constant has an integer part, a fraction part and an exponent part.

Here are some examples of floating point constants:

+---------------------------+
|1.2e3 4.2e+1 1.628e-94 |
|0.567 5e6 .67 |
+---------------------------+

String Constants

A string constant is represented as characters within double quotes
("). All characters in the script file are required to be printable, so special characters are represented by escape sequences. These escape sequences are:

+-----------------------------+
|\" the " character |
|\\ the \ character |
|\n Newline |
|\f Form Feed |
|\r Carriage Return |
|\b Backspace |
|\t Horizontal Tab |
|\nnn octal character value |
+-----------------------------+

Here are some examples of string constants:

+---------------------------------------------------+
|"Hello, World!" "Go away" "" |
| "The End0 "slosh is \\" "Say \"Please\"" |
+---------------------------------------------------+

Symbols

The non-alphanumeric characters are used to represent symbols, usually expression operators or statement terminators. The symbols used
include:

+--------------------------+
| ! != !~ ## ##= |
| % %= & && &= |
| ( ) * ** **= |
|*= + ++ += , |
| - -- -= . / |
|/= : ; < << |
|<<= <= = == > |
|>= >> >>= ? [ |
| ] ^ ^= { | |
||= || } ~ ~~ |
+--------------------------+

White Space

White space serves to separate words and symbols, and has no other
significance. The language is free-form. White space includes the
SPACE, TAB, FF, and NEWLINE characters.
Comments: Comments are delimited by /* and */ pairs, and are treated as a single white space character.

STATEMENTS

Statement serve to control the flow of execution of the program, or
the existence of variables.
The Expression Statement: The commonest statement consists of an expression terminated by a
semicolon. The expression is evaluated, and any result is discarded.; Examples of this statement include
x = 42;
print("Hello, World!0);
The If Statement: The if statement is used to conditionally execute portions of code. Examples if the if statement include:
if (x == 42)
x = 1;

if (x * x < 1)

print("no");

else

print("yes");
The For Statement: The for statement has two forms. The first form is described as
for (expr1; expr2; expr3)
stmt

The expr1 is done before the loop begins. The expr2 controls, the loop; if it does not evaluate to true the loop terminates. The loop
body is the stmt. The loop increment is done by the expr3, and the the test is performed again.

Each of the expressions is optional; any or all may be omitted.

Here is an example of a for loop:

for (j = 0; j < 10; ++j)
print(j);
The second form of the for statement looks like this:: for (name in keys(passwd))
print(name, passwd[name].pw_comment);
The Break Statement: The break statement is used to break out of a loop.; Here is an example of a break statement:
for (j = 0; ; j = 2 * j + 4)
{
print(j);
if (j >= 0x800)
break;

}

The break statement works within all loop statements.
The Continue Statement: The continue statement is used to terminate the loop body and start another repetition.; Here is an example of a continue statement:
for (j = 0; j < 1000; j = 2 * j + 4)
{
if (j < 42)
continue;

print(j);

}; The continue statement works within all loop statements.
The While Statement: The while statement is another loop construct. The condition is evaluated before the loop body.
line = 0;
while (line < 7)
{
print("");
++line;

}
The Do Statement: The do statement is another loop construct. The condition is evaluate after the loop body.
do
print("yuck");

while

(line++ < 7);
The Compound Statement: The compound statement is a way of grouping other statements together. It is enclosed in curly braces.
if ( lines < 7)
{
print("This\n");;
print("could\n");;
print("have\n");;
print("been\n");;
print("seven\n");;
print("blank\n");;
print("lines.\n");;

}
The Local Statement: The auto statement is used to declare variables and initialize them to be nul.
auto x, y, z;
x = 42;; All user-defined variables must be declared before they are used.
The Null Statement: The null statement does nothing. It consists of a single semicolon. It is most often seen as a loop body.
for (n = 0, bit = 1; n < bit_num; ++n, bit <<= 1)
;
The Try Catch Statement: The try catch statement is used to catch errors which would usually cause the report to fail.
try
statement1

catch (variable)

statement2

The first statement is executed. If no error occurs, nothing else is done. If an error occurs in the execution of the first statement the firsdt statement execution is terminated and then the given variable
is set to a description of the error and the second statement is executed.

EXPRESSIONS

Expressions are much the same as in C, using the same operators. The following table describes operator precedence and associativity:

[ ] subscripting value [ expr ]
( ) function call expr ( expr_list ) ( ) grouping ( expr )

++ post increment lvalue ++
++ pre increment ++lvalue
-- post decrement lvalue --- pre decrement --lvalue
~ compliment ~ expr
! not ! expr
- unary minus - expr
+ unary plus + expr

** exponentiation expr ** expr

* multiply expr * expr
/ divide expr / expr
% modulo (remainder) expr % expr
~~ matches expr ~~ expr
!~ does not match expr !~ expr
in list member expr in expr

+ addition (plus) expr + expr
- subtraction (minus) expr - expr
## list and string join expr ## expr

<< shift left expr << expr
>> shift right expr >> expr

< less than expr < expr
<= less than or equal expr <= expr
> greater than expr > expr
>= greater than or equal expr >= expr

== equal expr == expr
!= not equal expr != expr

& bitwise AND expr & expr

^ bitwise exclusive OR expr ^ expr

| bitwise inclusive OR expr | expr

? : arithmetic if expr ? expr : expr

= simple assignment expr = expr
*= multiply and assign expr *= expr
/= divide and assign expr /= expr
%= modulo and assign expr %= expr
+= add and assign expr += expr
-= subtract and assign expr -= expr
<<= shift left and assign expr <<= expr
>>= shift right and assign expr >>= expr
&= AND and assign expr &= expr
^= exclusive OR and assign expr ^= expr

|= inclusive OR and assign expr |= expr

, comma (sequencing) expr , expr

Most of these operators behave as they do in C, but some of these
operators will require some explanation.
Exponentiation: The ** operator raises the left argument to the right'th power. It is right associative.
Match: The ~~ operator compares two strings. It returns a number between 0.0 and 1.0. Zero means completely different, one means identical. Case is significant.
Not Match: The !~ is used to compare two strings, and returns the opposite of the ~~ operator; one if completely different, and zero if identical.
String Join: The ## operator is used to join two strings together.

TYPES

There are several types used within the report language.

array Values of this type contain other values, indexed by a string.: If you attempt to index by an arithmetic type, it will be
silently converted to a string. Use the keys function to determine all of the keys; use the count function to determine how many entries an array has. The type of an array element
is not restricted, only the index must be a string.
boolean This type has two values: true and false. These value arise: from the boolean operators described earlier.
integer This type is represented by the long C type. It has a limited: range of values (usually -2e9 to 2e9 approximately). If used in a string context, it will be silently converted to a
string. For exact control of the format, used the sprintf function.
list Values of this type contain a list of other values. The type: of these values is not restricted. The array index operator
(e[e]) may be used to access list elements; indexes start at
zero (0).
string Values of this type are an arbitrary string of C characters,: except the NUL character ( ). Strings may be of any length.
struct Values of this type contain additional values. These values: are accessed using the "dot" operator. These values may also be treated as if they were arrays.
real This type is represented the the double C type. If used in a: string context, it will be silently converted to a string.
For exact control of the format, used the sprintf function.

FUNCTIONS

There are a number of built-in functions.

basename: This function is used to extract the last element from a file path.
capitalize: This function converts it argument to a capitalized string in Title Case.
ceil This function is used to round a number to an integer, towards: positive infinity.
change_number: This function is used to determine the change number. It may be set by the -Change command line option, or it may default. The return value is an integer.
change_number_set: This function maybe used to determine if the change number was set by the -Change command line option. The return value is a boolean.
columns This function is used to define the report columns. Each: argument is a structure containing some or all of the following fields:

left the left margin, counting characters
from 0 on the left

right the right margin, plus one
width the width in characters, defaults to 7

if right not specified

padding white space between columns, defaults to

1 if not set

title the title for this column, separate mul

tiple lines with \n

The columns must be defined before the print function is used.
count This function is used to count the number of elements in a: list or array.
dirname This function is used to extract all but the last element from: a file path.
downcase: This functions converts its argument to lower case.
eject This function is used to start a new page of output.
floor This function is used to round a number to an integer, towards: negative infinity.
getenv This function is used to get the value of an environment vari: able. Will return the empty string if not set.
gettime This function is used to parse a string to produce a time. It: understands a variety of different date formats.
getuid This function takes no arguments, and returns the user ID of: the process which invoked the report generator. The return
value is an integer.
keys This function may be given an array or a list as argument. It: returns a list of keys which may be used to index the argument. Most often seen in for loops.
length This function is used to find the length of a string.
mktime This a synonym for the gettime function.
mtime This function may be used to obtain the modification time of a: file.
need This function is used to insert a page break into the report: if the required number of lines is not available before the
end of page. If sufficient lines are available, only a single blank line will be inserted. The return value is void.
now This function takes no arguments, and returns the current: time.
page_length: This function may be used to determine the length of the output page in lines. The return value is an integer.
page_width: This function may be used to determine the width of the output page in columns. The return value is an integer.
print This function is used to print into the defined columns. Col: umns will wrap around.
project_name: This function is used to determine the project name. It may
be set by the -Project command line option, or it may default. The return value is a string.
project_name_set: This function maybe used to determine if the project name was set by the -Project command line option. The return value is a boolean.
quote_html: This function quotes its argument string to insulate HTML special characters; these include "less than" (<), "ampersand"
(&) and non-printing characters. This is most often used to
generate suitable text for web pages.
quote_tcl: This function quotes its argument string to insulate TCL special characters; these include "[]" and non-printing characters. This is most often used to generate suitable text for
TCL interface scripts.
quote_url: This function quotes its argument string to insulate URL special characters; these include "?+#:&=" and non-printing characters. This is most often used to generate suitable text for web pages.
round This function is used to round a number to an integer, towards: the closest integer.
sort This function must be given a list as argument. The values: are sorted into ascending order. A new list is returned.
split This function is used to split a string into a list of: strings. The first argument is the string to split, the second argument is the character to split around.
sprintf This function is used to build strings. It is similar to the: sprintf(3) function.
strftime: This function is used to format times as strings. The first
argument is the format string, the second argument is a time. See the strftime(3) man page for more the format specifiers.
subst This function is used to substitute strings by regular expres: sion. The first argument is the pattern to match, the second argument is the substitution pattern, the third argument is
the input string to be substituted. The option fourth argument is the number of substitutions to perform; the default is as many as possible.
substr This function is used to extract substrings from strings. The: first argument is a string, the second argument is the starting position, starting from 0, and the third argument is the
length.
terse This function may be used to determine of the -TERse command: line option was used. The return type is a boolean.
title This function is used to set the title of the report. It: takes at most two arguments, one for each available title
line.
trunc This function is used to round a number to an integer, towards: zero.
typeof This function is used to determine the type of a value. The: return type is a string containing the name of the type, as
described in the
unquote_url: This function will remove URL quoting from the argument
string. URL quoting takes the form of a percent sign (%) followed by two hex digits. This is replaced by a single character with the value represented by the hex digits.
upcase This functions converts its argument to upper case.
working_days: This function is used to determine the number of working days between two times.
wrap This function is used to wrap a string into a list of strings.: The first argument is the wring to wrap, the second argument
is the maxmium width of the output strings.
wrap_html: This function is used to wrap a string into a list of strings. The first argument is the wring to wrap, the second argument
is the maxmium width of the output strings. This is very similar to the wrap functions, except thatit inserts HTML paragraph breaks <p> or line breaks <br> to reflect the newlines
within the string (2 or 1, respectively). TYPES section.

VARIABLES

There are a number of built-in variables.

arg This variable is a list containing the arguments passed on the: aer(1) command line.
change: There is a special type of variable created by using an
expression similar to project[project_name()].state.change[n] which contains all of the fields described in aecstate(5), plus some extras:; change Branches have a change array, just like project below.; change_number
The number of the change.
config This gives access to all of the fields described in: aepconf(5).
project_name: The name of the project containing the change.
src This gives access to the change files, and when: indexed by file name, yields a value conataining
fields as described in aefstate(5), for the src field.
group This variable is an array containing all of the entries in the: /etc/group file. Each entry is a structure with fields as documented in the group(5) manual entry. The gr_mem element is a list of strings. This array may be indexed by either a
string, treated as a group name, or by an integer, treated as a GID.
passwd This variable is an array containing all of the entries in the: /etc/passwd file. Each entry is a structure with fields as documented in the passwd(5) manual entry. This array may be indexed by either a string, treated as a user name, or by an
integer, treated as a uid.
project This variable is an array containing one entry for each aegis: project, indexed by name. Each array element is a structure, containing

name the project name
directory the root of the project directory tree
state the project state; The project state contains the fields documented in the aepstate(5) manual entry. Except: the change field is not a list of change numbers, it is an array indexed by change number of change states, as documented in the aecstate(5) manual entry. (See change, above.)
user This variable is an array containing the .aegisrc file of each: user. Each entry is a structure with fields as documented in the aeuconf(5) manual entry. This array may be indexed by either a string, treated as a user name, or by an integer,
treated as a uid. Files which are unreadable or absent will
generate an error, so you need to wrap accesses in a try/catch statement. (Note: count() and keys() functions think the
array is empty; if you want a list of users, consult the
passwd array.)

FILES

The reports are kept in the /usr/share/aegis/report directory. The reports are associated with a name by the
/usr/share/aegis/report.index file. Their names use the command line argument abbreviation scheme, so that report names may be abbreviated.

COPYRIGHT

aegis version 4.24.3.D001
Copyright (C) 1991, 1992, 1993, 1994, 1995, 1996, 1997, 1998, 1999,
2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010 Peter Miller

The aegis program comes with ABSOLUTELY NO WARRANTY; for details use
the 'aegis -VERSion License' command. This is free software and you are welcome to redistribute it under certain conditions; for details
use the 'aegis -VERSion License' command.

AUTHOR

Peter Miller E-Mail: millerp@canb.auug.org.au
/\/\* WWW: http://www.canb.auug.org.au/~millerp/

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