Categories of available functions:

plotting
arithmetic
strings
commalists
shell
sql
dates
times
misc

HOW TO USE FUNCTIONS

A number of functions are available for use in ploticus scripts and proc getdata filters , for a wide range of purposes including processing of arithmetic, strings dates, times, commalists , and so on. Functions usually take one or more arguments and return a value. Functions may be used with #set , #call or as operands in #if/#elseif conditional expressions .

Custom functions may be coded and added to the file custom.c, and accessed like any of the built in functions, except that the names of custom functions should begin with a double dollar sign ($$) when invoked from scripts.

FUNCTION SYNTAX

$formatfloat( @NUM, "%7.2f" )

Function calls may not be nested, ie. function arguments may not be functions.

In the following summaries, the function name appears along with a template for arguments that must be supplied.

PLOTTING

$inrange( value, axis ) or
$inrange( value, axis, min, max )

Return 1 if value within a range on the given axis. min and max are optional; if given they determine the range. If they are not given the range is the range of the axis within the plotting area.

$icolor( i )

Return one of 20 preselected colors. The color sequence was selected to give good contrast between nearby entries. i allowable range is 1 to 20; values out of this range are modulo into range.
Example: #set COLOR = $icolor( 2 )

$fieldname( n )

Return the field name assigned to field n. First is 1. If no field name was defined, noname is returned.

$dataitem( row, field )

Return the contents of the item in row and field of the current data set. row is a number, first is 1. field is either a number or an assigned name.

$data_to_absolute( axis, val )

Given a data location va in either X or Y space (specified by axis), return the absolute location.

$sleep( n )

Delay for n seconds. Occasionally useful when viewing plots interactively.

$getclick()

Produce a "More.." button and wait for user to click on it. Upon the click, return. Occasionally useful when viewing plots interactively.

ARITHMETIC AND NUMBERS

$arith( exp, format )

Simplistic arithmetic expression evaluator. exp is an expression made up of numbers and the arithmetic operators + - * /. No embedded spaces nor parentheses are allowed within the expression. Evaluation is strictly left to right. Unary plus/minus are allowed.
format is an optional printf(3) display format specifier controlling the format of the result, eg. %.0f. Default format is %g, which should suffice for all but very large or very small values. For more on format specifiers see your manual page on printf(3).
Example: #set RESULT = $arith(2+8/5) (result: 2)
Example: #set RESULT = $arith(2+-8) (result: -6)
Example: #set RESULT = $arith( 18*1000000000 , "%.f" )
Example: #set RESULT = $arith( 18*.0000001 , "%.9f" )

$arithl(exp)

Same as $arith() except lazy, i.e. non-numeric operands are accepted and treated as if they were 0.

$isnumber(s)

Returns 1 if s is a valid number, 0 if not.
Example: #set RESULT = $isnumber(-0.24) (result: 1)
Example: #set RESULT = $isnumber(=) (result: 0)

$formatfloat(x,fmt)

Format x using printf-style format string fmt. May also be used to format integers by using a fmt such as %03.0f.
Example: #set RESULT = $formatfloat( 3.4425, "%3.2f" ) (result: 3.44)

$inr(n,lo,hi)

See if n is within the numeric range of lo to hi. Returns 1 if so, 0 if not. Non-numeric n always returns 0.

$numgroup( val, h, mode )

Convert val to a nearby multiple of h. Useful in grouping a set of numbers into bins. mode may be either low, mid, or high. For example, if f is 73 and h is 10, function returns 70, 75, or 80 for modes low, mid, high respectively.

$autoround(val,d)

Round val to a reasonable precision. Use a value of 0 for d for normal behavior. Increase d to get more precision, reduce d to get less precision.
Example: #set X = $autoround( @X, 0 )

$math(what,a,b)

Mathematical functions.

what	returns
----    -------
abs	absolute value of a (integer or floating point)
mod	a modulo b (integer or floating point)
div	integer division a / b (where a and b are integers)

Example: #set X = $math(abs,-57) would return 57.
Example: #set X = $math(mod,10,6) would return 4.

$random()

Returns a random number between 0.0 and 1.0.

STRINGS

$len(s)

Return the length of s.

$change(s1,s2,string)

Change all occurances of s1 to s2 in string.
Example: #set T = $change( "<", "<sup>", @T )

$expand( s )

Expand all @variables present in s. Example:

 #set B = "@A world"
 #set A = hello
 #set C = $expand( @B )

Variable C would then contain hello world.

$substring(s,n,len)

Return a substring of s. Substring begins at character n (first is 1) for a maximum length of len.
Example: $substring( "abcde", 3, 99 ) would give cde

$changechars(clist,s,newchar)

If string s contains any of chars in clist, change that character to newchar. clist may be passed as the word comma to represent a comma (,).
Example: #set RESULT = $changechars("*'", @S, "_" )

$deletechars(clist,s)

If string s contains any of chars in clist, delete that character.
Example: #set RESULT = $deletechars("*'",@S)

$stripws( s )

Strip any leading or trailing whitespace from s.

$contains(clist,s)

If string s contains any of chars in clist, return position (first=1) of the first occurance. Return 0 if none found. clist may be passed as the word comma to represent a comma (,).
Example: #set RESULT = $contains( "*'", @S )
Example: #set RESULT = $contains( ",", @S )

$lowerc(string)

Return the lower-case equivalent of string.
Example: #set RESULT = $lowerc(HELLO) (result: hello)

$upperc(string)

Return the upper-case equivalent of string
Example: #set RESULT = $upperc(Hello) (result: HELLO)

$strcat(s,t)

Return the concatenatation of strings s and t
Example: #set RESULT = $strcat(ABC,XY) (result: ABCXY)

$ntoken( n, s )

return the nth whitespace-delimited token in s.

$extractnum( s )

extract the first numeric entity embedded anywhere in s and return it.

COMMALISTS

$count(str,list)

Count the number of times str appears in list. If str is passed as * then this function will count the number of members in the list.
Example: #set RESULT = $count( "hello,aba,gabba,jabba" ) (result: 0)
Example: #set RESULT = $count( "x", "x,y,x,y,y,z,x" ) (result: 3)

$addmember(newmem,list)

Append a new member newmem to end of list. If list is empty before call, result will have one member.
Example: #set RESULT = $addmember( "red", @MYLIST )

$nmember(n,list)

Get the nth member of list.
Example: #set RESULT = $nmember( 2, "a,b,c,d,e" ) (result: b)

$commonmembers( list1, list2, mode )

Detect if list1 and list2 have any members in common. Returns 0 if no members in common. If mode is "count", then the number in common is returned (for a,b,c vs. c,d,e this would be 1; for a,a,a vs a,b,c it would be 3). Otherwise, when a match is found 1 is returned immediately.
Example: #set MATCH = $commonmembers( "a,b,c,d,e", "c,d,ee", "count" ) (result: 2)

$homogenous( list )

Return 1 if all members of list are the same, 0 if there are any differences among members. If list has only 1 member, 1 is returned. If list is empty, 0 is returned.

$makelist( s )

Convert s, a list of items separated by commas and/or whitespace, and return a commalist. Useful for building commalists from user input.
Example: #set LIST = $makelist( "1101 1102 1103" ) (result: 1101,1102,1103)
Example: #set LIST = $makelist( "1101, 1102, 1103" ) (result: 1101,1102,1103)

SHELL COMMAND INTERFACE

SQL DATABASE INTERFACE

DATES

These functions work with dates in various notations.

The default date format is mmddyy. Unless otherwise specified, these functions expect date arguments to be in the "current date format".

$setdatefmt(format)

Set the current date format.
Example: #call $setdatefmt( "yyyymmdd" )

$formatdate(date,newformat)

Return date, formatted to newformat. Use to convert dates to different notations, to extract year, month, day components, or to get weekday equivalent. Available formats are described here
Example: #set RESULT = $formatdate( @D, "yyyymmmdd" )

$datevalid(date)

Return 1 if date is a valid one in the current date format; return 0 if it is not.
Example: #if $datevalid(@apptdate) != 1

$todaysdate()

Return the current date. It will be in the date format currently in effect.
Example: #set RESULT = $todaysdate()

$daysdiff(date1,date2)

Return the difference in days between date1 and date2.
Example: #set RESULT = $daysdiff( 011298, 010198 ) (result: 11)

$julian(date)

Return the julian (number of days since Jan 1, 1977) equivalent of date. date should be a date in current format, or the special symbol today.

$jultodate(jul)

Return the date (in current format) that is equivalent to julian value jul.

$dateadd(date,ndays)

Return the date resulting when ndays are added to date.
Example: #set RESULT = $dateadd( 010198, 11 ) (result: 011298)

$dategroup( interval, mode, input )

Take date, datetime, or time input value, and adjust it for grouping purposes. For example, after a set of dates are processed using $dategroup( week, mid, .. ), the result can be tabulated to get a weekly distribution. Allowable interval values are week month quarter year day hour. Allowable mode values are mid and first. First character is sufficient for these two args.

$yearsold(birthdate,testdate)

Return the integer age in years as of testdate of a person born on birthdate.
Example: #set RESULT = $yearsold( 062661, 022098 ) (result: 36)

$setdateparms(parmname,value)

Set a date parameter. See config file documentation for descriptions of these parameters, including strictness of date format checking, the century pivot year, and lazy dates.
A pivot year is used to accomodate two-digit year values.
A lazy date has 00 as the day and/or month portion and is usually used in situations where the day and/or month is unknown or unavailable.
Strictness of date format checking: by default the length of a presented date must be consistent with the format specification. For example, an mm/dd/yy date must be 8 or 10 characters long; other lengths result in an error. This strictness may be relaxed by doing: #set STATUS = $setdateparms(Strictdatelengths,no)
Example of setting the pivot year: #set STATUS = $setdateparms(Pivotyear,90)
Example of allowing lazy days: #set STATUS = $setdateparms(Lazydates,days)
Example of allowing lazy days and months: #set STATUS = $setdateparms(Lazydates,both)

TIMES

$settimefmt(fmt)

Set the current time notation to fmt. Available notations are HH:MM:SS, HH:MM, and MM:SS. (A leading HH can handle single digit hour values; a leading MM can handle single digit minute values).
Example: #set RESULT = $settimefmt(MM:SS) These functions work with time values.

$time()

Return the current time in hh:mm:ss format.
Example: #set RESULT = $time()

$timevalid(time)

Return 1 if time is valid in the current time format; return 0 if it is not.
Example: #if $timevalid(@appttime) != 1

$formattime(time,newformat)

Take time, which is in the current time format, and reformat it using newformat.
Example: #set t2 = $formattime( "14:22", "hh:mma" )

$timesec()

Get number of seconds since midnight for the current time.
Example: #set RESULT = $timesec()

$tomin(t)

Take t (a value in the current time notation) and return the equivalent, expressed in # of minutes since 0:00:00. Result is float, with any seconds expressed as the decimal portion of a minute.
Example: #set RESULT = $tomin( "3:45" )

$frommin(m)

Inverse of $tomin(), where m is a float minutes value. Result is equivalent time in current notation.
Example: #set RESULT = $frommin( 3.75 )

$timediff(t1,t2)

Find the difference between two times t1 and t2 (both in current notation). Result is expressed in float minutes (any seconds expressed as fraction of a minute)
Example: #set RESULT = $timediff( "3:43", "2:28" )

CHECKSUMS

$checksumvalid(s)

Returns 1 if s is a valid number with checksum. 0 if not.
Example: #if $checksumgood(39) = 1 (result: true)

$checksumencode(i)

Result is integer i with a checksum digit appended.
Example: #set CHECKNUM = $checksumencode(29) (result: 294)

$checksumnext(s)

Take s which is a number including trailing checksum digit, and increment the number and recompute new checksum digit. Result is returned. Example: #set RESULT = $checksumnext(39) = 1 (result: 41)

MISCELLANEOUS

$getenv(varname)

Return the contents of environment variable varname.

$errormode( mode )

Control the display of error messages. Allowable values for mode are stderr and stdout. For command line applications the default is generally stderr; for CGI applications it is stdout, so that messages are visible. To hide error messages in CGI applications, set mode to stderr.

$uniquename()

Return a short identifier generated using the current date, time to the current second, and process id. The name will be unique on a per-host basis.

$tmpfilename(tag)

Generate a unique (on a per-host basis) temporary file name, suitable for use in shell commands. Uses tmpdir as specified in project config file . Format of the name is tmpdir/tag.uniquename where uniquename is a short name generated using the current date, current time to the second, and process id. tag may be passed as a zero length string if desired.

$fileexists( dir, name )

Return 1 if the requested file can be opened, 0 otherwise. dir indicates the directory that name is relative to and may be one of /, scriptdir, tmpdir. dir may also be datadir if using pocketSQL; this currently requires that a database access be executed earlier in the page.
Example: #set A = $fileexists( tmpdir, "mytmp" )

$ref( varname )

Return the contents of varname. May be useful when a variable contains the name of another variable, to extract the value of the other variable. Example:

  #set A = "hello"
  #set B = "A"
  #set C = $ref(@B)

C would then contain hello.

$def( varname )

Return 1 if varname has been set to a value. Return 0 otherwise.

$isleep( n )

Delay for n seconds.