Manual

Programmer's Guides

C++

ICONV/OCONV PATTERNS

Decimal (MD/MC)

input	conversion	output
1234	MD2	12.34
1234	MD20	1234.00
1234	MD20,	1,234.00
1234.5678	MD2	12.35
1234.5678	MD20	1234.57
1234.5678	MD20,	1,234.57
1234	MC2	12,34
1234	MC20	1234,00
1234	MC20,	1.234,00
1234	MD20-	1234.00

Date (D)

input	conversion	output
12345	D	18 OCT 2001
12345	D/	10/18/2001
12345	D-	10-18-2001
12345	D2	18 OCT 01
12345	D/E	18/10/2001
12345	DS	2001 OCT 18
12345	DS/	2001/10/18
12345	DM	10
12345	DMA	OCTOBER
12345	DY	2001
12345	DY2	01
12345	DD	18
12345	DW	4
12345	DWA	THURSDAY
12345	DQ	4
12345	DJ	291
12345	DL	31

Time (MT)

input	conversion	output
234800	MT	17:13
234800	MTH	05:13PM
234800	MTS	17:13:20
234800	MTHS	05:13:20PM
0	MT	00:00
0	MTH	12:00AM
0	MTS	00:00:00
0	MTHS	12:00:00AM

Hex (HEX/MX)

input	conversion	output
ab	HEX	(same as HEX8 or HEX4 depending on platform)
ab	HEX8	0000006100000062
ab	HEX4	00610062
ab	HEX2	6162
15	MX	F
254	MX	FE
255	MX	FF
256	MX	100
27354234	MX	1A1647A

Text (L/R/T)

input	conversion	output
abcd	L#3	abc
ab	L#3	ab␣
abcd	R#3	bcd
ab	R#3	␣ab
ab	T#3	ab␣
abcd	T#3	abc™d␣␣
42	L(0)#5	42000
42	R(0)#5	00042
42	T(0)#5	42000

Dictionaries

Exodus dictionaries enable classic multivalue database data definition. Dictionaries are just normal Exodus multivalue files that contain one record for each data column definition. You can use Exodus's edir program to manually edit dictionaries.

Dictionary file names must start with the word "dict_". For example, if you have a "books" file, then you will probably have a "dict_books" file.

You can list the contents of a dictionary by typing "list dict_filename".

Exodus Dictionary Format

0	DICTID	Field/Column Code
1	DICTTYPE	"F" or "S" : "F" means use Field No (i.e. raw data) and "S" means use Source Code (i.e. a function).
2	FIELDNO	Field number (0=key, 1=field 1 etc for "Fields"
3	TITLE	Title on reports
4	SM	S or M or Mnn : "Single Value" or "Multivalue" or "Multivalue Group nn"
5	KEYPARTNO	Multipart keys are separated by * characters.
6
7	CONVERSION	Conversion (MD/MT/D etc.)
8	SOURCE	Source Code of a subroutine to calculate the field. Multivalues are lines and the result must be placed in a variable "ANS".
9	JUST	"L" or "R" or "T" requesting left, right or text justification
10	WIDTH	Column Width on fixed width reports

Exodus Dictionary Subroutines

"S" type file dictionary entries define table columns that are derived by calling a subroutine.

Dictionary subroutines can be executed in two cases.

1. During a SSELECT command e.g. SELECT USERS WITH AGE_IN_YEARS > 10
2. In any Exodus program using the Exodus's "calculate" function. e.g. calculate("AGE_IN_YEARS")

Dictionary Subroutine Library Format

Dictionary subroutines are a simplified type of Exodus external subroutine.

A dictionary subroutine is in the format "dict(xyz){...}" where xyz is the dictionary field key *without* quotes and ... is one or more lines of ordinary Exodus source code.

The source code may contain calculate() statements that obtain the results of other dictionary fields.

The source code must result in the variable ANS being set with the required result.

Return statement(s) may be placed anywhere in the code but are not required.

They are slightly different from ordinary external subroutines and do not have programinit()/programexit() clauses. In OO terms, this means that they are simple global functions and not classes, therefore:

1. No global variables
2. Any local subroutines or functions must be defined before (above) the dictionary subroutine.

All the subroutines related to one dictionary file go in one "external subroutine library" which can either be written manually or generated automatically from the source code in field 8 of S type dictionaries using the "compile dict_USERS" command.

The library name must be the same as the dictionary file name unless a "USING dictfilename" clause is included in the SSELECT or LIST command.

edic dict_USERS

#include <exodus/dict.h>

dict(AGE_IN_DAYS) {
        ANS=date()-RECORD(1);
}

dict(AGE_IN_YEARS) {
        ANS=calculate("AGE_IN_DAYS")/365.25;
}

Dictionary subroutine variables

Dictionary subroutines have access to the following variables.

When using "calculate(dictid)" the programmer is responsible for setting all these variables (with the exception of ANS) *before* the calculate() expression.

Variable	Purpose
ID	The database record key.
RECORD	The database record
DICT	The dictionary file name.
MV	The required multivalue number or 0 for all.
ANS	Dictionary subroutines return their result in ANS.

Sort/Select Command

Exodus provides the classic multivalue sort/select command within any Exodus program followed by readnext().

Classic multivalue select/readnext functions only provide the keys of the selected records. Exodus provides the classic select/readnext and also selectrecords/readnextrecord which provides complete records instead of just keys.

The format of the select/sselect command is as follows:

 SELECT|SSELECT

 {max_number_of_records}

 {using filename}

 filename

 {datakeyvalue} ...

 {BY|BY-DSND fieldname} ...
 
 {

  WITH

  {NO|ALL|ANY}

  dict_field_id

  {
   CONTAINING|STARTING|ENDING|LIKE|EQ|NE|NOT|GT|LT|GE|LE=|<>|>|<|>=|<= value(s)
   |
   BETWEEN value AND value
  }

  {AND|OR}

 } ...

Traditional Multivalue Functions and Statements (non-OO)

Exodus clones traditional multivalue function and statement behaviour and retains their syntax as far as possible.

• Traditional functions are rendered as Exodus functions.
• Traditional statements are rendered as Exodus subroutines.

PRINT OCONV(DATE(),'D')

in Exodus becomes:

printl(oconv(date(),"D"));

String Commands

The use of most of Exodus's functions will be fairly obvious to traditional multivalue programmers.

Ηοwever it is not so obvious that all the functions ending in "-er" correspond to the old string commands.

For example, the classic multivalue "modify in-place" character conversion command:

CONVERT 'ab' TO 'cd' IN ZZ

is now represented in Exodus by:

converter(zz,"ab","cd");

Exodus provides a complete set of string modification commands even where there was no specific command in classic mv basic.

To guarantee fast performance (regardless of compiler optimisation) you should always use the command instead of the old "self assign" idiom.

For example:

ZZ=TRIM(ZZ)

should appear in Exodus as:

trimmer(zz);

and not:

zz=trim(zz);

Function Types

TYPE	FUNCTION TYPE
var=	traditional functions that return values and can be used in expressions and be on the right hand side of assignments
if	traditional conditional statements that started with "if" or ended with "then/else" (or could have)
cmd	traditional commands with no outputs
cmd2	traditional commands that now have outputs and can be used in expressions

Parameters/Argument Types

in	Parameters that provide data to the function. Can be variables or raw data like 1 or "X"
unspecified	Same as "in". Omission of the most common type de-clutters the documentation. NB When defining your own subroutines and functions "in" cannot be omitted from the source code.
io	Parameters that may provide and/or return data. Must be variables. Cannot be raw data like 1 or "X"
out	Parameters that return data. Must be variables. Cannot be raw data like 1 or "X"

Optional Parameters

Key	Default
=""	""
=" "	" "
="."	"."
=1	1
=0	0
=true	true
=false	false

Complete List of Functions

Environment

var=	osgetenv(envname)
if	osgetenv(envname, out value)
if	ossetenv(envname, newvalue)

Time/Date/Sleep

var=	date()
var=	time()
var=	timedate()
cmd	ossleep(milliseconds)
var=	ostime()

System File

if	osopen(filename, out filehandle, in locale="")
cmd	osclose(filehandle)
var=	osbread(filehandle, startoffset, length)
cmd	osbread(out data, filehandle, startoffset, length)
cmd	osbwrite(data, filehandle, startoffset)
if	osread(out data, osfilename, in locale="")
var=	osread(osfilename, in locale="")
if	oswrite(data, osfilename, in locale="")
if	osdelete(osfilename)
if	osrename(oldosdir_or_filename, newosdir_or_filename)
if	oscopy(fromosdir_or_filename, newosdir_or_filename)
cmd	osflush()

System Directory

var=	oslist(path=".", wildcard="", mode=0)
var=	oslistf(path=".", wildcard="")
var=	oslistd(path=".", wildcard="")
var=	osfile(filename)
var=	osdir(filename)
if	osmkdir(newdirname)
if	osrmdir(dirname, evenifnotempty=false)
var=	oscwd()
var=	oscwd(newdirname)

Program Control

var=	suspend(command)
var=	osshell(command)
var=	osshellread(command)
cmd	osshellread(out commandoutput, command)
cmd	osshellwrite(commandinput, command)
cmd	stop(text="")
cmd	abort(text)
var=	perform(command)
var=	execute(command)
var=	chain(command)
var=	logoff()
cmd	debug()

Variable Control

if	assigned(anyvar)
if	unassigned(anyvar)
cmd2	exchange(var1,var2)
cmd2	transfer(fromvar,tovar)

Console Output

cmd	print(instring)
cmd	printl(instring="")
cmd	printt(instring="")

Cursor

var=	at(column0orcode)
var=	at(column0, row0)
var=	getcursor()
cmd	setcursor(cursorstr)
var=	getprompt()
cmd	setprompt(promptchar)

Console Input

var=	input()
var=	input(out inputstr)
var=	input(prompt, out inputstr)
var=	inputn(n)

Math

var=	rnd(number)
cmd	initrnd(seednumber)
var=	mod(dividend, divisor)
var=	abs(number)
var=	pwr(base, exponent)
var=	exp(power)
var=	sqrt(number)
var=	sin(degrees)
var=	cos(degrees)
var=	tan(degrees)
var=	atan(number)
var=	loge(number)
var=	integer(number)
var=	floor(number)
var=	round(number, ndecimals=0)

String Creation

var=	chr(integer)
var=	str(instring, number)
var=	space(number)

String Info/Search

var=	count(instring, substr)
var=	dcount(instring, substr)
var=	index(instring, substr, occurrenceno=1)
var=	index2(instring, substr, startcharno=1)
var=	len(instring)
var=	length(instring)
if	match(instring, matchstr, options="")
var=	seq(inchar)

String Functions

var=	convert(instring, oldchars, newchars)
var=	crop(instring)
var=	field(instring, sepchar, fieldno, nfields=1)
var=	field2(instring, sepchar, fieldno, nfields=1)
var=	fieldstore(instring, sepchar, fieldno, nfields, replacementstr)
var=	lcase(instring)
var=	ucase(instring)
var=	lower(instring)
var=	raise(instring)
cmd2	quote(instring)
cmd2	squote(instring)
cmd2	unquote(instring)
var=	splice(instring, fromcharno, nchars, insertionstr)
var=	substr(instring, fromcharno)
var=	substr(instring, fromcharno, nchars)
var=	swap(instring, oldstr, newstr, options="")
var=	trim(instring, trimchars=" ")
var=	trimb(instring, trimchars=" ")
var=	trimf(instring, trimchars=" ")

String Commands

cmd2	converter(io instring, oldchars, newchars)
var=	cropper(io instring)
cmd2	fieldstorer(io instring, sepchar, fieldno, nfields, replacementstr)
cmd2	lcaser(io instring)
var=	ucaser(io instring)
cmd2	lowerer(io instring)
cmd2	raiser(io instring)
cmd2	quoter(io instring)
cmd2	squoter(io instring)
cmd2	unquoter(io instring)
cmd2	splicer(io instring, fromcharno, nchars, insertion)
var=	substrer(io instring, fromcharno)
var=	substrer(io instring, fromcharno, nchars)
cmd2	swapper(io instring, oldstr, newstr, options="")
cmd2	trimmer(io instring, trimchars=" ")
cmd2	trimmerb(io instring, trimchars=" ")
cmd2	trimmerf(io instring, trimchars=" ")

iconv/oconv

var=	oconv(instring, conversion)
var=	iconv(instring, conversion)

Database

if	connect(connectionstring="")
if	disconnect()
if	createdb(dbname, out errmsg)
if	deletedb(dbname, out errmsg)
if	createfile(filename, options="")
if	deletefile(filename)
if	clearfile(filename)
var=	listfiles()
if	createindex(filename, fieldname, usingdictfilename="")
if	deleteindex(filename, fieldname)
var=	listindexes(filename="")
if	begintrans()
if	rollbacktrans()
if	committrans()

Database Files and Records

if	open(filename, out filehandle)
if	read(out record, filehandle, key)
if	matread(out dimrecord, filehandle, key)
if	readv(out record, filehandle, key, fieldnumber)
if	write(record, filehandle, key)
if	matwrite(in dimrecord, filehandle, key)
if	writev(record, filehandle, key, fieldn)
if	deleterecord(filehandle, key)
if	updaterecord(record, filehandle, key)	the record key must already exist
if	insertrecord(record, filehandle, key)	the record key must not already exist
if	lock(filehandle, key)
cmd	unlock(filehandle, key)
cmd	unlockall()

Record Selection

if	select(sortselectclause="")
cmd	clearselect()
if	readnext(out key)
if	readnext(out key, out valueno)	valueno returns multivalue numbers if your sortselectclause sorted BY-EXP on a multivalued field. Not implemented yet.
if	selectrecord(sortselectclause="")
if	readnextrecord(out record, out id)	must be preceded by a selectrecord() not select()

Dictionary

var=	calculate(fieldname)
var=	xlate(filename, key, fieldno, mode)

Dynamic Array Functions

var=	replace(instring, fieldno, replacement)
var=	replace(instring, fieldno, valueno, replacement)
var=	replace(instring, fieldno, valueno, subvalueno, replacement)
var=	extract(instring, fieldno, valueno=0, subvalueno=0)
var=	erase(instring, fieldno, valueno=0, subvalueno=0)
var=	insert(instring, fieldno, insertion)
var=	insert(instring, fieldno, valueno, insertion)
var=	insert(instring, fieldno, valueno, subvalueno, insertion)
if	locate(instring, target, out setting, fieldn=0, valuen=0)
if	locateby(instring, target, ordercode, out setting, fieldn=0, valuen=0)
if	locateusing(instring, target, usingchar, out setting, fieldn=0, valuen=0, subvaluen=0)
if	locateusing(instring, target, usingchar)
var=	remove(fromstr, io startx, out delimiterno)
var=	sum(instring, sepchar=VM_)

Dynamic Array Commands

cmd2	replacer(io instring, fieldno, replacement)
cmd2	replacer(io instring, fieldno, valueno, replacement)
cmd2	replacer(io instring, fieldno, valueno, subvalueno, replacement)
cmd2	inserter(io instring, fieldno, insertion)
cmd2	inserter(io instring, fieldno, valueno, insertion)
cmd2	inserter(io instring, fieldno, valueno, subvalueno, insertion)
cmd2	eraser(io instring, fieldno, valueno=0, subvalueno=0)

Troubleshooting

printl(lcaser("ABC")); //won't compile!

Simply use lcase instead of lcaser.

printl(lcase("ABC"));  //result is abc

lcaser is designed to modify a variable so lcaser's parameter must be a variable and not raw data like "ABC".

aa(10)=bb; //compiles but doesnt do anything!

To replace field 10 of dynamic array aa do one of the following.

replacer(aa,10,bb);
aa.replacer(10,bb);

Exodus doesnt support "aa(10)=" style syntax to replace dynamic array fields.

if (aa ^ bb > cc) //won't compile!

If the intent is to work like classic multivalue basic code then put brackets to clarify that to the compiler.

if ( (aa ^ bb) > cc)

If instead the intent is aa ^ (bb > cc) then you must pre-calculate the result of bb > cc ...

var dd=bb > cc;
if (aa ^ dd)

... or just wrap it in var()

if (aa ^ var(bb>cc) )

Exodus will not treat the direct result of a logical operation as a character "1" or "0" for the purposes of string concatenation. This is the only deliberate difference from multivalue Basic in Exodus. For why this is so, read about Exodus's concatenation operator.

using asserts

Asserts may be used to trap some errors in Exodus code. Typical scheme to use asserts:

// near beginning of .cpp file:
#include <cassert>
...
// somewhere in the code:
assert( some_expression_that_should_be_normally_true);

If some_expression_that_should_be_normally_true happens to be false, the program aborts with message printed to console.

Exodus has 3 additional include files which modify or extend the functionality of standard cassert file.

cassert_warn - redefines all assert()s to display diagnostic message when triggered, but not to abort() the program;

cassert_pause - redefines all assert()s to display diagnostic message when triggered, and then pause the program until user presses a key; macro does not abort() the program;

cassert_exodus - defines assert() macro in the standard way, but adds 2 more macros: assert_warn( some_expression_that_should_be_normally_true) - message, no abort(); assert_pause( some_expression_that_should_be_normally_true) - message, pause until keypress, no abort().

For simple examples - click on assert_examples.