#set TITLE = FUNCTIONS
#include top

#if @PL != 1
.SH NAME
functions
#endif //PL
.LP
Categories of available functions:
.LP
#if @PL = 1
#set FILE = "functions.html#ploticus"
#set TAG = "plotting"
#include link
.br
#endif
#set FILE = "functions.html#arithmetic"
#set TAG = arithmetic
#include link
.br
#set FILE = "functions.html#strings"
#set TAG = strings
#include link
.br
#set FILE = "functions.html#commalists"
#set TAG = commalists
#include link
.br
#set FILE = "shell.html"
#set TAG = shell command processing
#include link
.br
#set FILE = "sql.html"
#set TAG = sql result processing
#include link
.br
#if @PL != 1
  #set FILE = "functions.html#html"
  #set TAG = HTML formatting
  #include link
.br
#endif
#set FILE = "functions.html#dates"
#set TAG = dates
#include link
.br
#set FILE = "functions.html#times"
#set TAG = times
#include link
.br
#set FILE = "functions.html#misc"
#set TAG = misc


#include space

.SH HOW TO USE FUNCTIONS
.LP
A number of functions are available for use in 
#set FILE = scripts.html
#set TAG = "scripts
#include link
, for a wide range of purposes including processing of arithmetic, strings
dates, times, 
#set FILE = commalist.html
#set TAG = "commalists
, and so on.  
Functions usually take one or more arguments and return a value.
Functions may be used with 
#set FILE = set.html
#set TAG = "#set
#include link
,
#set FILE = call.html
#set TAG = "#call
#include link
, or as operands in
#set FILE = if.html
#set TAG = "#if/#elseif
#include link
#set FILE = condex.html
#set TAG = "conditional expressions
#include link
\0.  
#if @CGIPAL = 0
They may also be accessed from shell scripts using the
#set FILE = tdhfunction.1.html
#set TAG = "tdhfunction(1) utility
#include link
\0.
#endif
.LP
Custom functions may be coded and added to the file \fCcustom.c\fR,
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.

#include space

.SH FUNCTION SYNTAX
Function names always start with a dollar sign (\fB$\fR).
Function arguments are enclosed by parentheses and if more than one
argument, separated by commas (,).  For example:
.IP
\fC$formatfloat( @NUM, "%7.2f" )\fR
.LP
Function calls may not be nested, ie. function arguments may not be functions.

#include space

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

#if @PL = 1
#include space
.ig >>
<a name=ploticus></a>
.>>
.SH PLOTTING
Note: the functions in this section may be used with a double dollar sign ($$)
for faster function name search.
.LP
\fB$inrange( value, axis )\fR   or
.br
\fB$inrange( value, axis, min, max )\fR
.IP
Return 1 if \fIvalue\fR within a range on the given \fIaxis\fR.
\fImin\fR and \fImax\fR 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.

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

.LP
\fB$fieldname( n )\fR
.IP
Return the field name assigned to field \fIn\fR.  First is 1.
If no field name was defined, \fCnoname\fR is returned.

.LP
\fB$dataitem( row, field )
.IP
Return the contents of the item in \fIrow\fR and \fIfield\fR of
the current data set.  \fIrow\fR is a number, first is 1.
\fIfield\fR is either a number or an assigned name.

.LP
\fB$data_to_absolute( axis, val )\fR
.IP
Given a data location \fIva\fR in either X or Y space (specified by
\fIaxis\fR), return the absolute location.

.LP
\fB$nextstub( maxlen )\fR
.IP
Returns the text of a defined category or pltab row stub.
Usually called multiple times within a loop; the result is used to build an expression to
select data rows.  The first time it is called, the first category or row stub text will 
be returned; second time, the second category or row stub text will be returned, and so on.
The length will be limited to \fImaxlen\fR.  Any embedded spaces will be converted to underscores.
.IP
Example: \fC#set S = $nextstub(5)\fR
.IP
A gallery example where this is used is
#set FILE = "../tabgallery/caselist.html"
#set TAG = "caselist"
#include link

.LP
\fB$sleep( n )\fR
.IP
Delay for \fIn\fR seconds.  
Occasionally useful when viewing plots interactively.

.LP
\fB$getclick()\fR
.IP
Produce a "More.." button and wait for user to click on it.
Upon the click, return.
Occasionally useful when viewing plots interactively.

#endif //PL

.ig >>
<a name=arithmetic></a>
.>>
#include space

.SH ARITHMETIC AND NUMBERS

.LP
\fB$arith(exp)\fP 
.IP
Simplistic arithmetic expression evaluator. 
\fIexp\fR is an expression made up of numbers and the arithmetic operators
\fC+ - * /\fR.
No embedded spaces nor parentheses are allowed within the expression.
Evaluation is strictly left to right.
Unary plus/minus are allowed.
.br
Example: \fC#set RESULT = $arith(2+8/5)\fP  (result: 2)
.br
Example: \fC#set RESULT = $arith(2+-8)\fP  (result: -6)

.LP
\fB$arithl(exp)\fP
.IP
Same as \fB$arith()\fP except 
lazy, i.e. non-numeric operands 
are accepted and treated as if they were 0.  

.LP
\fB$isnumber(s)\fP
.IP
Returns 1 if \fIs\fP is a valid number, 0 if not.
.br
Example: \fC#set RESULT = $isnumber(-0.24)\fR  (result: 1)
.br
Example: \fC#set RESULT = $isnumber(=)\fR  (result: 0)

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

.LP
\fB$inr(n,lo,hi)\fR
.IP
See if \fIn\fR is within the numeric range of \fIlo\fR
to \fIhi\fR.  Returns 1 if so, 0 if not.  Non-numeric \fIn\fR always returns 0.

.LP
\fB$autoround(val,d)\fR
.IP
Round \fIval\fR to a reasonable precision.
Use a value of 0 for \fId\fR for normal behavior.  Increase \fId\fR to
get more precision, reduce \fId\fR to get less precision.
.br
Example: \fC#set X = $autoround( @X, 0 )\fR

.LP
\fB$math(what,val)\fR
.IP
Mathematical functions on \fIval\fR.  
.nf
what	returns
----    -------
abs	absolute value (integer or floating point)
.fi
.br
Example: \fC#set X = $math(abs,@X)\fR

.LP
\fB$random()\fR
.IP
Returns a random number between 0.0 and 1.0.

.ig >>
<a name=strings></a>
.>>
#include space

.SH STRINGS

.LP
\fB$len(s)\fR
.IP
Return the length of \fIs\fR.

.LP
\fB$change(s1,s2,string)\fR
.IP
Change all occurances of \fIs1\fR to \fIs2\fR in string.
.br
Example: \fC#set T = $change( "<", "<sup>", @T )\fR

.LP
\fB$substring(s,n,len)\fR
.IP
Return a substring of \fIs\fR.  Substring begins at character \fIn\fR (first is 1)
for a maximum length of \fIlen\fR.
.br
Example: \fC$substring( "abcde", 3, 99 )\fR would give \fCcde\fR


.LP
\fB$changechars(clist,s,newchar)\fR
.IP
If string \fIs\fR contains any of chars in \fIclist\fR, change that
character to \fInewchar\fR.  
\fBclist\fR may be passed as the word \fCcomma\fR to represent a comma (,).
.br
Example: \fC#set RESULT = $changechars("*'", @S, "_" )\fR

.LP
\fB$deletechars(clist,s)\fR
.IP
If string \fIs\fR contains any of chars in \fIclist\fR, delete that character.
.br
Example: \fC#set RESULT = $deletechars("*'",@S)\fR

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

.LP
\fB$fuzzymatch(s1,s2,degree)\fR
.IP
Perform an approximate match of \fIs1\fR against \fIs2\fR.
A wildcard character '*' at the beginning or end of \fIs2\fR indicates
that a match can occur anywhere within \fIs1\fR (eg. smith* would match
smithington and *smith would match harrowsmith; *smith* would match
both).  If there are no asterisks, lengths of the two strings must be similar.
.br
\fIdegree\fR changes the 'looseness' of the match.
5 = strict, 4 = medium-strict, 3 = medium 2= loose, 1 = very loose.
.br
Returns 1 on a match, 0 not.
.br
Example: \fC#set STAT = $fuzzymatch(hello,hillo,3)\fP (result: \fC1\fR)
.br
Example: \fC#set STAT = $fuzzymatch(hello,hillo,5)\fP (result: \fC0\fR)


.LP
\fB$lowerc(string)\fP
.IP
Return the lower-case equivalent of \fIstring\fP.
.br
Example: \fC#set RESULT = $lowerc(HELLO)\fP (result: \fChello\fP)

.LP
\fB$upperc(string)\fP
.IP
Return the upper-case equivalent of \fIstring\fP
.br
Example: \fC#set RESULT = $upperc(Hello)\fP (result: \fCHELLO\fP)


.LP
\fB$strcat(s,t)\fP
.IP
Return the concatenatation of strings \fIs\fP and \fIt\fP
.br
Example: \fC#set RESULT = $strcat(ABC,XY)\fP  (result: \fCABCXY\fP)

.LP
\fB$ntoken( n, s )\fR
.IP
return the \fIn\fRth whitespace-delimited token in \fIs\fR.

.LP
\fB$extractnum( s )\fR
.IP
extract the first numeric entity embedded anywhere in \fIs\fR and return it.


.ig >>
<a name=commalists></a>
.>>
#include space

.SH COMMALISTS
These functions operate on a string which is in the form of a 
#set FILE = commalist.html
#set TAG = "commalist
#include link
\0.

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

.LP
\fB$addmember(newmem,list)\fP
.IP
Append a new member \fInewmem\fR to end of \fIlist\fR.
If \fIlist\fR is empty before call, result will have one member.
.br
Example: \fC#set RESULT = $addmember( "red", @MYLIST )\fR

.LP
\fB$nmember(n,list)\fP
.IP
Get the \fIn\fPth member of \fIlist\fP.  
.br
Example: \fC#set RESULT = $nmember( 2, "a,b,c,d,e" )\fP (result: \fCb\fB)

.LP
\fB$commonmembers( list1, list2, mode )
.IP
Detect if \fIlist1\fR and \fIlist2\fR have any members in common.
Returns 0 if no members in common.
If \fImode\fR is \fC"count"\fR, then the number in common is returned.
Otherwise, when a match is found 1 is returned immediately.
.br
Example: \fC#set MATCH = $commonmembers( "a,b,c,d,e", "c,d,ee", "count" )\fR  (result: \fC2\fR)

.LP
\fB$makelist( s )\fR
.IP
Convert \fIs\fR, a list of items separated by commas and/or whitespace, 
and return a commalist.
Useful for building commalists from user input.
.br
Example: \fC#set LIST = $makelist( "1101   1102 1103" )\fR  (result: \fC1101,1102,1103\fR)
.br
Example: \fC#set LIST = $makelist( "1101,  1102, 1103" )\fR  (result: \fC1101,1102,1103\fR)

.ig >>
<a name=shell></a>
.>>
#include space

.SH SHELL COMMAND INTERFACE
Functions related to the shell interface are described on the
#set FILE = "shell.html"
#set TAG = "#shell manual page"
#include link
\0.


.ig >>
<a name=sql></a>
.>>
#include space

.SH SQL DATABASE INTERFACE
Functions related to SQL interface are described on the
#set FILE = "sql.html"
#set TAG = "#sql manual page"
#include link
\0.

#if @PL != 1
.ig >>
<a name=html></a>
.>>

#include space
.SH HTML
The following functions are useful when generating HTML.
.LP
\fB$htmlquote( var1, ..varN )\fR
.IP
Convert embedded double quote (") characters to \fC&quot;\fR,
for all variables named.
Allows proper display of variables as \fCvalues\fR on form <input> fields.
Any number of variable names may be supplied.
An alternative is to use HTML quoting mode (see
#set FILE = config.html
#set TAG = config
#include link
).
.br
Example: 
.nf
\0 #call $htmlquote( name, address, city, state )
\0 <input name=name size=20 value="@name">
\0 <input name=name size=20 value="@address">
\0 ...etc..
.fi

.LP
\fB$htmldisplay( var1, ..varN )\fR
.IP
Convert embedded HTML special characters (\fC<\fR, \fC>\fR, \fC&\fR)
to their HTML escape codes, for all variables named.
Allows proper display of variable contents as raw HTML.
Any number of variable names may be supplied.
.br
Example: \fC#call $htmldisplay( name, address )\fR

#endif //PL

.ig >>
<a name=dates></a>
.>>
#include space

.SH DATES
.LP
These functions work with 
#set FILE = dates.html
#set TAG = "dates in various notations
#include link
\0.  Some date-related parameters may be set in the 
#set FILE = config.html
#set TAG = "project config file
#include link
.LP
The default date format is \fCmmddyy\fR.
Unless otherwise specified, these functions expect date arguments
to be in the "current date format".

.LP
\fB$setdatefmt(format)\fR
.IP
Set the current date format.
.br
Example: \fC#call $setdatefmt( "yyyymmdd" )\fR

.LP
\fB$formatdate(date,newformat)\fR
.IP
Return \fIdate\fR, formatted to \fInewformat\fR.
Use to convert dates to different notations, to extract year, month, day
components, or to get weekday equivalent.
Available formats are described 
#set FILE = dates.html
#set TAG = "here
#include link
.br
Example: \fC#set RESULT = $formatdate( @D, "yyyymmmdd" )\fR

.LP
\fB$datevalid(date)\fR
.IP
Return 1 if \fIdate\fR is a valid one in the current date format;
return 0 if it is not.
.br
Example: \fC#if $datevalid(@apptdate) != 1\fR

.LP
\fB$todaysdate()\fR
.IP
Return the current date.  It will be in the date format currently in effect.
.br
Example: \fC#set RESULT = $todaysdate()\fR

.LP
\fB$daysdiff(date1,date2)\fR
.IP
Return the difference in days between \fIdate1\fR and \fIdate2\fR.
.br
Example: \fC#set RESULT = $daysdiff( 011298, 010198 )\fR (result: 11)

.LP
\fB$julian(date)\fR
.IP
Return the julian (number of days since Jan 1, 1977) equivalent of \fIdate\fR.
\fIdate\fR should be a date in current format, or the special symbol \fCtoday\fR.

.LP
\fB$jultodate(jul)\fR
.IP
Return the date (in current format) that is equivalent to julian value \fIjul\fR.

.LP
\fB$dateadd(date,ndays)\fR
.IP
Return the date resulting when \fIndays\fR are added to \fIdate\fR.  
.br
Example: \fC#set RESULT = $dateadd( 010198, 11 )\fR (result: 011298)

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

.LP
\fB$yearsold(birthdate,testdate)\fR
.IP
Return the integer age in years as of 
\fItestdate\fR of a person born on \fIbirthdate\fR.
.br
Example: \fC#set RESULT = $yearsold( 062661, 022098 )\fR (result: 36)

.LP
\fB$setdateparms(parmname,value)\fR
.IP
Set a date parameter.  See 
#set FILE = config.html
#set TAG = "config file documentation
#include link
for descriptions of these parameters, including
strictness of date format checking, 
the century pivot year, and lazy dates.
.br
A pivot year is used to accomodate two-digit year values.
.br
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.
.br
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: \fC#set STATUS = $setdateparms(Strictdatelengths,no)\fR
.br
Example of setting the pivot year: \fC#set STATUS = $setdateparms(Pivotyear,90)\fR
.br
Example of allowing lazy days: \fC#set STATUS = $setdateparms(Lazydates,days)\fR
.br
Example of allowing lazy days and months: \fC#set STATUS = $setdateparms(Lazydates,both)\fR

.ig >>
<a name=times></a>
.>>
#include space

.SH TIMES
These functions work with 
#set FILE = times.html
#set TAG = "time values"
#include link
in various notations.

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

.LP
\fB$time()\fP
.IP
Return the current time in \fChh:mm:ss\fR format.
.br
Example: \fC#set RESULT = $time()\fP

.LP
\fB$timevalid(time)\fR
.IP
Return 1 if \fItime\fR is valid in the current time format;
return 0 if it is not.
.br
Example: \fC#if $timevalid(@appttime) != 1\fR

.LP
\fB$formattime(time,newformat)\fR
.IP
Take \fItime\fR, which is in the current time format,
and reformat it using \fInewformat\fR.
.br
Example: \fC#set t2 = $formattime( "14:22", "hh:mma" )

.LP
\fB$timesec()\fP
.IP
Get number of seconds since midnight for the current time.
.br
Example: \fC#set RESULT = $timesec()\fP

.LP
\fB$tomin(t)\fR
.IP
Take \fIt\fR (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. 
.br
Example: \fC#set RESULT = $tomin( "3:45" )\fR
 
.LP
\fB$frommin(m)\fR
.IP
Inverse of $tomin(), where \fIm\fR is a float minutes value.
Result is equivalent time in current notation.
.br
Example: \fC#set RESULT = $frommin( 3.75 )\fR

.LP
\fB$timediff(t1,t2)\fR
.IP
Find the difference between two times 
\fIt1\fR and \fIt2\fR (both in current notation).  Result is expressed 
in float minutes (any seconds expressed as fraction of a minute) 
.br
Example: \fC#set RESULT = $timediff( "3:43", "2:28" )\fR

.ig >>
<a name=checksums></a>
.>>
#include space

.SH CHECKSUMS
Checksum routines use an odd-even algorithm that takes an integer and
computes a checksum digit 0 - 9 or x.  This checksum digit may be
used to guard against key errors and transposed digits.
.LP

\fB$checksumvalid(s)\fP
.IP
Returns 1 if \fIs\fR is a valid
number with checksum.  0 if not.
.br
Example: \fC#if $checksumgood(39) = 1\fR (result: true)

.LP
\fB$checksumencode(i)\fR
.IP
Result is integer \fBi\fR with 
a checksum digit appended.
.br
Example: \fC#set CHECKNUM = $checksumencode(29)\fR (result: 294)

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


.ig >>
<a name=misc></a>
.>>
#include space

.SH MISCELLANEOUS
.LP
\fB$getenv(varname)\fR
.IP
Return the contents of environment variable \fIvarname\fR.


.LP
\fB$uniquename()\fR
.IP
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.

.LP
\fB$tmpfilename(tag)\fR
.IP
Generate a unique (on a per-host basis) temporary file name, suitable
for use in shell commands.  Uses \fBtmpdir\fR as specified in
#set FILE = "config.html
#set TAG = "project config file
#include link
\0.  Format of the name is \fItmpdir\fC/\fItag\fC.\fIuniquename\fR where
\fIuniquename\fR is a short name generated using the current date, current time
to the second, and process id.  \fItag\fR may be passed as a zero length string
if desired.

.LP
\fB$fileexists( dir, name )\fR
.IP
Return 1 if the requested file can be opened, 0 otherwise.
\fIdir\fR indicates the directory that \fIname\fR is relative to
and may be one of \fC/\fR, \fCscriptdir\fR, \fCdatadir\fR, \fCtmpdir\fR.
.br
Example: \fC#set A = $fileexists( tmpdir, "mytmp" )\fR

.LP
\fB$ref( varname ) \fR
.IP
Return the contents of \fIvarname\fR.  May be useful when a variable contains
the name of another variable, to extract the value of the other variable.
Example:
.br
.nf
\0 #set A = "hello"
\0 #set B = "A"
\0 #set C = $ref(@B)
.fi
.br
C would then contain \fChello\fR.

.LP
\fB$def( varname ) \fR
.IP
Return 1 if varname has been set to a value.
Return 0 otherwise.

// .LP
// \fB$system(command)\fP
// .IP
// Execute the given shell \fIcommand\fP and return
// the first line of standard output produced by the command, 
// without trailing newline.
// .br
// Example: \fC#set RESULT = $system( "date" )\fP


#include bottom
