Manual: Difference between revisions

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=== Hello World ===
=== Programmer's Guides ===


After installing Exodus, you can develop Exodus programs from any operating system command line.
Only for C++ at the moment. For all others, see some examples:
http://code.google.com/p/exodusdb/source/browse/#svn%2Ftrunk%2Fswig%2Fshare


This introduction concentrates on simple development from the command line because it is common to all platforms.
==== [[Python]] ====
 
==== [[Perl]] ====
==== Edit ====
==== [[PHP]] ====
 
==== [[Java]] ====
Use Exodus's all-in-one editor+compiler+cataloger 'edic'
==== [[C#]] ====
 
==== [[C++]] ====
edic hello1
 
edic will give you a skeleton Exodus program which you can develop as you wish.
 
There must be one and only one "function main()" statement and this is run when the program is started.
 
By convention, main() must return an integer value. If desired, this can be used to indicate "success" with zero or "failure" with some error number.
 
The programinit() and programexit() lines are required and provide all the standard multivalue system variables using a simple C++ class macro.
 
<pre>
#include <exodus/program.h>
 
programinit()
 
function main() {
        printl("hello1 says 'Hello World!'");
        return 0;
}
 
programexit()
</pre>
 
==== Save and compile ====
 
Make any changes you fancy to the skeleton and save it.
 
NB Even if you just want to try out the skeleton program exactly as it is without any changes, you must still explicitly save it - otherwise, if you just exit without saving,  edic will assume you didn't want a hello1 program, and will cancel. For the default editor (nano), explicit save is usually Ctrl+O.
 
Upon saving hello1, edic will compile and catalog it.
 
==== Run ====
 
To run/open/execute your new hello1 program just type its name.
 
hello1
 
and the output is ...
 
hello1 says 'Hello World!'
 
=== Deployment of Compiled Programs ===
 
All programs you develop with Exodus's edic or compile commands are stored in the same directory as their source code. They are also copied to a folder in your home directory. This folder is called "Exodus" on Windows and bin or lib on other operating systems.
 
On Windows, the user who installs Exodus can run any program they develop in Exodus by typing its name at any command prompt. It does not matter what the current working directory is because the Exodus installer permanently adds the Exodus home program directory to the PATH of the user who installs it.
 
Users other than the user who installed Exodus on Windows, and all users on Linux, Mac or other operating systems, must type "exodus" at a command prompt (or open an Exodus console from an application menu) before they can run any program they develop in Exodus. Once they have done that, it does not matter what the current working directory is because the "exodus" program temporarily adds the Exodus home program directory to the users PATH.
 
On all operating systems, if there is a similarly named program earlier on in your path (e.g. operating system commands) then you will not be able to run your program because in all cases Exodus adds its path (to your home program directory) to the end of your existing path - not the beginning.
 
To make any developed Exodus programs available to other users you must arrange for them to be copied to some directory on their path.
 
=== Local subroutines ===
 
To simulate classic multivalue basic's "gosub/return" in Exodus, you can add additional subroutines and functions between the programinit() and programexit() lines.
 
You can add them either above or below the "main" function. There is no rule that functions must appear before or above the code that calls them.
 
Subroutines and functions cannot be nested otherwise compilation will fail. In other words, no function or subroutine can be contain within the body of another.
 
==== Simple Example ====
 
Here is hello1 modified to call a subroutine that says something.
 
The word "gosub" is just there for classical clarity. It could be omitted. It could also be replaced by "call" which is also a throwaway word. While gosub and call are interchangeable, if you are going to use them at all, it is probably a good idea to use "gosub funcx()" to indicate internal subroutines and "call funcx()" to indicate external subroutines.
 
<pre>
#include <exodus/program.h>
 
programinit()
 
function main() {
        printl("hello1 says 'Hello World!'");
 
        gosub subr1();
 
        return 0;
}
 
subroutine subr1() {
        printl("subr1 says 'Hello'");
}
 
programexit()
</pre>
 
output:
 
hello1 says 'Hello World!'
subr1 says 'Hello'
 
=== Subroutine and Function Parameters (Arguments) ===
 
Parameter names must be prefixed by "in", "out" or "io" to indicate if they are inbound, outbound or both.
 
Inbound parameters (prefixed with "in") cannot be amended within the function and the compiler will enforce this. This provides a guarantee to the programmer calling the subroutine or functions that their inbound parameters will not be modified by calling the function. Inbound parameters may be provided by the calling program either as a variable or as raw data like "xyz" or 123 etc.
 
In/Outbound parameters ("io") must be provided by the calling program in the form of a variable and not raw data. The function can both read and write into these parameters.
 
Outbound parameters ("out") indicate to the programmer using the function how it works. However, outbound parameters do not actually prevent them being used to provide data to the subroutine or function and are therefore no different from in/outbound parameters. There is no simple way to enforce "write only" parameters using the underlying C++ language.
 
For special cases, or where performance is critical, the usual C++ parameters are also allowed for example "int arg1" or "const char* arg2" etc.
 
=== External functions and subroutines ===
 
Editing and compiling external subroutines and functions in Exodus is identical to normal programs except:
 
#the word "program" becomes "library" so we have "library.h", "libraryinit()" and "libraryexit()".
#function main can have any parameters you like, for example: "function main(in arg1, in arg2, out arg3)
 
NB The name of the function internally MUST be main and not the name of the function so we still have "function main(...)" but this time it can have parameter names eg "subroutine main(in instr1, out outstr2)".
 
External functions and subroutines are implemented as dll or so files and are only loaded into memory the first time that they are used. A missing function or subroutine so or dll file will not cause any failure unless and until it is first used.
 
==== Example func1 ====
 
edic func1
 
<pre>
#include <exodus/library.h>
 
libraryinit()
 
function main(in arg1, out arg2) {
        printl("func1 says 'Hello World!'");
        arg2="arg1 was "^arg1;
        return 999;
}
 
libraryexit()
</pre>
 
==== Example prog1 using func1 ====
 
Compiling func1 created a func1.h file that is required to "glue" func1 into any program that wants to use func1.
 
To use func1 in any program or external subroutine or function, you need to insert an #include "func1.h" somewhere between "programinit()" and "programexit()" - and not within the body of any function or subroutine.
 
edic prog1
 
<pre>
#include <exodus/program.h>
 
programinit()
 
//you must "declare" that we want to use func1
#include "func1.h"
 
function main() {
        printl("prog1 says 'Hello World!'");
 
        //we print what func1 returns, and also what func1 returns in arg2
        var arg2;
        printl(  func1("myarg1",arg2)  );
        printl(arg2);
 
        return 0;
}
 
programexit()
</pre>
 
run prog1
 
prog1
 
output:
 
prog1 says 'Hello World!'
func1 says 'Hello World!'
999
arg1 was myarg1
 
=== Functions versus Subroutines ===
 
Functions can be used anywhere an expression would be used whereas subroutines can only be used as statements.
 
The same principle applies to both internal and external subroutines/functions.
 
Both subroutines and functions can return information in any of their "out" or "io" arguments.
 
The word "call" or "gosub" before the use of a function or subroutine is optional and can be omitted.
 
==== Functions ====
 
Functions return a value so you can use them anywhere an expression is required, for example on the right hand side of an assignment.
 
var yy=funcx(xx);
 
Even though a function returns a value, the value it returns can be ignored so the following are all equivalent.
 
call funcx(xx);
gosub funcx(xx);
funcx(xx);
 
==== Subroutines ====
 
Subroutines do not return a value so they can only be used as statements.
 
call subrx(xx); 
gosub subrx(xx); 
subrx(xx);       
var yy=subrx(xx); //will not compile
 
=== Differences between Exodus's Internal Subroutines and Functions and those of classic multivalue basic ===
 
Exodus's internal subroutines and functions are very different from and arguably much better than classic multivalue internal subroutines. They are very similar to external subroutines and functions except they also have access to the global variables of the main program.
 
Exodus Internal Subroutines and Functions:
 
#can be called with parameters e.g. gosub funcx(xx,yy,zz)
#only have access to the main programs global variables - this eliminates a major category of multivalue bugs
#functions (not subroutines) can return a result e.g. abc=funcx(xx,yy,zz)
 
Exodus internal subroutines and functions only have one entry point. In classic multivalue basic you can jump into the middle of any internal subroutine. To simulate this type of coding in Exodus you must create a hierarchy of subroutines or functions that call each other.
 
The old RETURN TO XYZ syntax is not supported at all and such code must be redesigned to eliminate it.
 
==== Moving external subroutines and functions to internal ====
 
Exodus allows many classic multivalue basic external subroutines and functions to be reimplemented as internal subroutines and functions. This means that you can now, where appropriate, keep all source code related to one and only one program in a single file. This is a major improvement in source code management.
 
In classic multivalue basic, if you wanted to implement some function to be used in expressions you were forced to implement it as an external function requiring a separate source code file.
 
In classic multivalue basic if you wanted to call a subroutine with parameters, or you wanted to be sure that a subroutine would not accidentally overwrite main program variables, you were forced to implement it as an external subroutine or function.
 
In Exodus the above situations no longer force you to have separate compilation and source files. However you can still make subroutines and functions external exactly as before where that is the best strategy, for example:
 
#to provide some common feature to more than one program
#to avoid having to recompile the whole of a large program when you just change part of it
#where there is some benefit in not loading all the parts of a program into memory immediately on start-up.
 
NB Exodus internal subroutines and functions have access to the global variables of the main program so you might want them to make them external to make sure that there is no risk that they touch any global variable.
 
=== Dimensioned Arrays ===
 
{|border="1" cellpadding="10" cellspacing="0"
!statement!!effect
|-
|dim arraya(10);      ||create a one dimensional array with 10 elements
|-
|dim arrayb(20,30);  ||create two dimensional array with 20x30 elements
|-
|dim arraryc=arrayb;  ||create a new array from an existing array;
|-
|arrayb="";    ||initialise all elements to ""
|-
|arrayb(15,3)="abc";  ||set element 15,3 to "abc"
|-
|var xx=arrayb(15,3); ||get element 15,3
|-
|arrayd=arrayc;      ||copy the elements of one array to another. If the arrays are of different sizes then only overlapping columns and rows are copied and all others are set to "". If the target array has not been dimensioned then the array is duplicated.
|-
|arrayb.redim(15,20); ||destroy all data and redimension the array to 15x20
|-
|var nfields=matparse(record1,arrayb); ||create a dimensioned array "arrayb" from a dynamic array/string "record1" and return the number of elements.
|-
|var record1=matunparse(arrayb); ||create a dynamic array/string "record1" from a dimensioned array "arrayb"
|}
 
=== Operators ===
 
 
==== Operator Precedence ====
 
{|border="1" cellpadding="10" cellspacing="0"
!priority!!operators!!effect!!associativity
|-
|1||X++&nbsp;&nbsp;X--&nbsp;&nbsp;()&nbsp;&nbsp;.&nbsp;&nbsp;|| evaluate then increment/decrement || right
|-
|2|| ++X&nbsp;&nbsp;--X&nbsp;&nbsp;+&nbsp;&nbsp;-&nbsp;&nbsp;not|| increment/decrement then evaluate.<br>positive, negative, logical negation || left
|-
|3||*&nbsp;&nbsp;/&nbsp;&nbsp;% || multiply, divide, remainder || right
|-
|4|| +&nbsp;&nbsp;- || add, subtract || right
|-
|5|| lt&nbsp;&nbsp;le&nbsp;&nbsp;ge&nbsp;&nbsp;gt || compare less than, less than or equal, greater than or equal, greater than ||right
|-
|6||eq&nbsp;&nbsp;ne || compare equal, not equal ||right
|-
|7||^ || concatenate  ||right
|-
|8||and || logical union || right
|-
|9||or || logical alternative || right
|-
|10||=&nbsp;&nbsp;+=&nbsp;&nbsp;-=&nbsp;&nbsp;*=&nbsp;&nbsp;/=&nbsp;&nbsp;%=&nbsp;&nbsp;^= || self update||left
|}
 
==== Logical and comparative operators ====
 
{|border="1" cellpadding="10" cellspacing="0"
!word||example!!symbolic<br>alternative
|-
|and||if (aa and bb)||&&
|-
|or||if (aa or bb)||&#x7c;&#x7c;
|-
|not||if (not aa)||!
|-
|eq||if (aa eq bb)||==
|-
|ne||if (aa ne bb)||!=
|-
|gt||if (aa gt bb)||>
|-
|lt||if (aa lt bb)||<
|-
|le||if (aa le bb)||<=
|-
|ge||if (aa ge bb)||>=
|}
 
==== and/or short circuiting ====
 
If the left hand side of an "or" operator is true then the right hand side is not even evaluated. Similarly, if the left hand side of an "and" operator is false then the right hand side is not even evaluated.
 
This provides a major programming convenience/performance advantage over classic multivalue basic.
 
if (aa eq 1 and bb eq 1) // if aa is not 1 then bb is not checked and could even be unassigned.
if (aa eq 1 or bb eq 1)  // if aa is 1 then bb is not checked and could even be unassigned.


=== ICONV/OCONV PATTERNS ===
=== ICONV/OCONV PATTERNS ===
Line 338: Line 17:


{|border="1" cellpadding="10" cellspacing="0"
{|border="1" cellpadding="10" cellspacing="0"
!input!!conversion!!output
!input!!conversion (string)!!output
|-
|-
|1234||MD2||12.34
|1234||MD2||12.34
Line 362: Line 41:
|-1234||MD20-||1234.00-
|-1234||MD20-||1234.00-
|}
|}


==== Date (D) ====
==== Date (D) ====


{|border="1" cellpadding="10" cellspacing="0"
{|border="1" cellpadding="10" cellspacing="0"
!input!!conversion!!output
!input!!conversion (string)!!output
|-
|-
|12345||D||18 OCT 2001
|12345||D||18 OCT 2001
Line 403: Line 81:
|12345||DL||31
|12345||DL||31
|}
|}


==== Time (MT) ====
==== Time (MT) ====


{|border="1" cellpadding="10" cellspacing="0"
{|border="1" cellpadding="10" cellspacing="0"
!input!!conversion!!output
!input!!conversion (string)!!output
|-
|-
|234800||MT||17:13
|234800||MT||17:13
Line 430: Line 107:


{|border="1" cellpadding="10" cellspacing="0"
{|border="1" cellpadding="10" cellspacing="0"
!input!!conversion!!output
!input!!conversion (string)!!output
|-
|-
|ab||HEX||(same as HEX8 or HEX4 depending on platform)
|ab||HEX||(same as HEX8 or HEX4 depending on platform)
Line 454: Line 131:


{|border="1" cellpadding="10" cellspacing="0"
{|border="1" cellpadding="10" cellspacing="0"
!input!!conversion!!output
!input!!conversion!! (string)output
|-
|-
|abcd||L#3||abc
|abcd||L#3||abc
Line 508: Line 185:
|-
|-
|10||WIDTH||Column Width on fixed width reports
|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.
# During a SSELECT command e.g. SELECT USERS WITH AGE_IN_YEARS > 10
# In any Exodus program using the Exodus's "calculate" function. e.g. calculate("AGE_IN_YEARS")
Dictionary subroutines are normal Exodus external subroutines.
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.
===== Dictionary Subroutine Library Format =====
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
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.
<pre>
#include <exodus/dict.h>
dict(AGE_IN_DAYS) {
        ANS=date()-RECORD(1);
}
dict(AGE_IN_YEARS) {
        ANS=calculate("AGE_IN_DAYS")/365.25;
}
</pre>
===== 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.
|-
|}
|}


Line 610: Line 226:
  } ...
  } ...
</pre>
</pre>
(where "value" is any string quoted with " or ' or numbers)


=== Traditional Multivalue Functions and Statements (non-OO) ===
=== Traditional Multivalue Functions and Statements (non-OO) ===
Line 667: Line 281:
|cmd ||traditional commands with no outputs||
|cmd ||traditional commands with no outputs||
|-
|-
|cmd2 ||traditional commands that had parameters on the left hand side of the = assigments (or -er functions)||
|cmd2 ||traditional commands that now have outputs and can be used in expressions||
|}
|}


Line 734: Line 348:


{|border="1" cellpadding="10" cellspacing="0"
{|border="1" cellpadding="10" cellspacing="0"
|if ||osopen(filename, out filehandle)||
|if ||osopen(filename, out filehandle, in locale="")||
|-
|-
|cmd ||osclose(filehandle)||
|cmd ||osclose(filehandle)||
Line 744: Line 358:
|cmd ||osbwrite(data, filehandle, startoffset)||
|cmd ||osbwrite(data, filehandle, startoffset)||
|-
|-
|if ||osread(out data, osfilename)||
|if ||osread(out data, osfilename, in locale="")||
|-
|-
|var= ||osread(osfilename)||
|var= ||osread(osfilename, in locale="")||
|-
|-
|if ||oswrite(data, osfilename)||
|if ||oswrite(data, osfilename, in locale="")||
|-
|-
|if ||osdelete(osfilename)||
|if ||osdelete(osfilename)||
|-
|-
|if ||osrename(oldosfilename, newosfilename)||
|if ||osrename(oldosdir_or_filename, newosdir_or_filename)||
|-
|-
|if ||oscopy(fromosdir_or_filename, newosdir_or_filename)||
|if ||oscopy(fromosdir_or_filename, newosdir_or_filename)||
Line 758: Line 372:
|cmd ||osflush()||
|cmd ||osflush()||
|}
|}


===== System Directory =====
===== System Directory =====
Line 811: Line 424:




===== Status =====
===== Variable Control =====


{|border="1" cellpadding="10" cellspacing="0"
{|border="1" cellpadding="10" cellspacing="0"
Line 817: Line 430:
|-
|-
|if    ||unassigned(anyvar)||
|if    ||unassigned(anyvar)||
|-
|cmd2    ||exchange(var1,var2)||
|-
|cmd2    ||transfer(fromvar,tovar)||
|}
|}


Line 881: Line 498:
|var=    ||tan(degrees)||
|var=    ||tan(degrees)||
|-
|-
|var=    ||atan(degrees)||
|var=    ||atan(number)||
|-
|-
|var=    ||loge(number)||
|var=    ||loge(number)||
Line 925: Line 542:


===== String Functions =====
===== String Functions =====
Return new and doesnt change original.


{|border="1" cellpadding="10" cellspacing="0"
{|border="1" cellpadding="10" cellspacing="0"
Line 946: Line 565:
|-
|-
|cmd2  ||quote(instring)||
|cmd2  ||quote(instring)||
|-
|cmd2  ||squote(instring)||
|-
|-
|cmd2  ||unquote(instring)||
|cmd2  ||unquote(instring)||
Line 965: Line 586:


===== String Commands =====
===== String Commands =====
Modify original in place


{|border="1" cellpadding="10" cellspacing="0"
{|border="1" cellpadding="10" cellspacing="0"
Line 983: Line 606:
|-
|-
|cmd2  ||quoter(io instring)||
|cmd2  ||quoter(io instring)||
|-
|cmd2  ||squoter(io instring)||
|-
|-
|cmd2  ||unquoter(io instring)||
|cmd2  ||unquoter(io instring)||
Line 1,004: Line 629:


{|border="1" cellpadding="10" cellspacing="0"
{|border="1" cellpadding="10" cellspacing="0"
|var= ||oconv(instring, conversion)||
|var= ||oconv(instring, conversionstring)||
|-
|-
|var= ||iconv(instring, conversion)||
|var= ||iconv(instring, conversionstring)||
|}
|}


Line 1,032: Line 657:
|if ||deleteindex(filename, fieldname)||
|if ||deleteindex(filename, fieldname)||
|-
|-
|var= ||listindexes(filename)||
|var= ||listindexes(filename="")||
|-
|-
|if    ||begintrans()||
|if    ||begintrans()||
Line 1,047: Line 672:
|-
|-
|if ||read(out record, filehandle, key)||
|if ||read(out record, filehandle, key)||
|-
|if ||matread(out dimrecord, filehandle, key)||
|-
|-
|if ||readv(out record, filehandle, key, fieldnumber)||
|if ||readv(out record, filehandle, key, fieldnumber)||
|-
|-
|if ||write(record, filehandle, key)||
|if ||write(record, filehandle, key)||
|-
|if ||matwrite(in dimrecord, filehandle, key)||
|-
|-
|if ||writev(record, filehandle, key, fieldn)||
|if ||writev(record, filehandle, key, fieldn)||
Line 1,056: Line 685:
|if ||deleterecord(filehandle, key)||
|if ||deleterecord(filehandle, key)||
|-
|-
|if ||updaterecord(record, filehandle, key)||
|if ||updaterecord(record, filehandle, key)||the record key must already exist
|-
|-
|if ||insertrecord(record, filehandle, key)||
|if ||insertrecord(record, filehandle, key)||the record key must not already exist
|-
|-
|if    ||lock(filehandle, key)||
|if    ||lock(filehandle, key)||
Line 1,076: Line 705:
|if ||readnext(out key)||
|if ||readnext(out key)||
|-
|-
|if ||readnext(out key, out valueno)||
|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 ||selectrecord(sortselectclause="")||
|-
|-
|if ||readnextrecord(out key, out record)||
|if ||readnextrecord(out record, out id)||must be preceded by a selectrecord() not select()
|}
|}


===== Dictionary =====
===== Dictionary =====
Line 1,094: Line 722:


===== Dynamic Array Functions =====
===== Dynamic Array Functions =====
Return modified, dont change original


{|border="1" cellpadding="10" cellspacing="0"
{|border="1" cellpadding="10" cellspacing="0"
Line 1,102: Line 732:
|var=    ||replace(instring, fieldno, valueno, subvalueno, replacement)||
|var=    ||replace(instring, fieldno, valueno, subvalueno, replacement)||
|-
|-
|var= ||extract(instring, fieldno=0, valueno=0, subvalueno=0)||
|var= ||extract(instring, fieldno, valueno=0, subvalueno=0)||
|-
|-
|var= ||erase(instring, fieldno, valueno=0, subvalueno=0)||
|var= ||erase(instring, fieldno, valueno=0, subvalueno=0)||
Line 1,126: Line 756:


===== Dynamic Array Commands =====
===== Dynamic Array Commands =====
Modify original in place


{|border="1" cellpadding="10" cellspacing="0"
{|border="1" cellpadding="10" cellspacing="0"

Latest revision as of 16:12, 4 November 2014

Programmer's Guides

Only for C++ at the moment. For all others, see some examples: http://code.google.com/p/exodusdb/source/browse/#svn%2Ftrunk%2Fswig%2Fshare

Python

Perl

PHP

Java

C#

C++

ICONV/OCONV PATTERNS

Decimal (MD/MC)

input conversion (string) 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 (string) 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 (string) 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 (string) 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 (string)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

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

Return new and doesnt change original.

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

Modify original in place

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, conversionstring)
var= iconv(instring, conversionstring)
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

Return modified, dont change original

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

Modify original in place

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)