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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
                               multiple 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
               variable.  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.
               Columns 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
               expression.  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.

SEE ALSO

       aer(1)  report generator

       aecstate(5)
               change state description

       aepstate(5)
               project state description

       aerptidx(5)
               report index file format

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/