rem ----------------------------------------
rem ADDON V1.5.7
rem ----------------------------------------
rem Example code to create external math
rem functions for application Calc3a.
rem (c) Alfa Computing 1996
rem email@ 100735.331@compuserve.com
rem        rschmidt@worldonline.nl
rem ----------------------------------------
rem To have access to these external math
rem functions:
rem - add your own functions to this file
rem - register them by adding them to
rem   procedure "register:"
rem - compile this file
rem - make sure this file is placed in
rem   an \OPD directory
rem - start Calc3a application
rem - enter number(s)
rem - press diamond key
rem - enter hotkey
rem
rem ----------------------------------------
rem Procedures available for interfacing
rem with Calc3a application:
rem
rem PROC RegFunc:(key$,func$)
rem Register your function to the Calc3a
rem application.
rem key$  - single character hotkey (a..z, A..Z)
rem func$ - function name to link to hotkey
rem         do not contain ":" in function
rem         name.
rem The number of functions to register is
rem limited to 52.
rem
rem PROC GetStatX:(Elm%)
rem Get X-element Elm% from statistic memory
rem Available in SD and LR mode
rem
rem PROC SetStatX:(Elm%,Value)
rem Set X-element Elm% in statistic memory
rem Available in SD and LR mode
rem
rem PROC GetStatY:(Elm%)
rem Get Y-element Elm% from statistic memory
rem Only available in LR mode
rem
rem PROC SetStatY:(Elm%,Value)
rem Set Y-element Elm% in statistic memory
rem Only available in LR mode
rem
rem PROC GetElm%:
rem Number of elements in statistic memory
rem
rem PROC SetRes:(Result)
rem Send result to calculator
rem
rem PROC GetRes:
rem Get last result from calculator
rem
rem GetOp1:
rem Get operand 1
rem
rem GetOp2:
rem Get operand 2
rem
rem NOTE : only characters a..z and A..Z are
rem        allowed for in function names.

rem ----------------------------------------
rem This procedure must always be in the
rem addon file and will be called during the
rem initialisation of Calc3a. It registers
rem all math functions and hotkeys to the
rem program

PROC Register:
		RegFunc:("i","Interst")
		RegFunc:("v","VecLen")
		RegFunc:("p","PolyLen")
		RegFunc:("k","KeyCode")
		RegFunc:("g","gLog")
		RegFunc:("d","dBlist")
ENDP

rem ----------------------------------------
rem Example : Length of polyline (defined
rem           by XY co-ordinates) in statistic
rem           memory. Calculator must be in LR
rem           mode to perform this calculation.

PROC PolyLen:
		LOCAL length,i%,x1,y1,x2,y2

		rem Number of co-ordinate pairs must
		rem be two or more.
		IF GetElm%:<=1
				RETURN
		ENDIF

		rem Calculate length of polyline
		i%=1
		WHILE i%<GetElm%:
				rem Get vector
				x1=GetStatX:(i%)
				y1=GetStatY:(i%)
				x2=GetStatX:(i%+1)
				y2=GetStatY:(i%+1)
				length=length+SQR((x2-x1)**2+(y2-y1)**2)
				i%=i%+1
		ENDWH

		rem Send result to calculator
		SetRes:(length)
ENDP

rem ----------------------------------------
rem Example : Calculate length of vector
rem           from point 0,0 to point x,y
rem           x and y must be entered by the user:
rem           e.g. 10<,>5<diamond><v>

PROC VecLen:
		LOCAL x,y,length

		rem store operand 1 in x
		x=GetOp1:
		rem store operand 2 in y
		y=GetOp2:
		length=SQR(x**2+y**2)

		rem Send result to calculator
		SetRes:(length)
ENDP

rem ----------------------------------------
rem Example : Determine key code

PROC KeyCode:
		LOCAL k%,km%

		BUSY "Press any key"
		k%=GET
		km%=KMOD
		BUSY OFF
		GIPRINT "KEY="+GEN$(k%,3)+"  KMOD="+GEN$(km%,3)
ENDP

rem ----------------------------------------
rem Example : g-BASE logarithm of x

PROC gLog:
	LOCAL r,a,g

	g=GetOp1:
	a=GetOp2:
	IF (g<=0) OR (a<=0)
		RETURN
	ENDIF

	r=log(a)/log(g)
	rem Send result to calculator
	SetRes:(r)
ENDP

rem ----------------------------------------
rem Example : Add dB numbers in stat memory

PROC dBlist:
		LOCAL total,i%

		rem Number of dB numbers must
		rem be two or more.
		IF GetElm%:<=1
				SetRes:(GetStatX:(1))
				RETURN
		ENDIF

		rem Calculate total
		i%=1
		WHILE i%<=GetElm%:
				rem get number
				total=total+(10**(GetStatX:(i%)/10))
				i%=i%+1
		ENDWH

		rem Calculate total of energetic
		rem values
		IF total>0
				total=10*LOG(total)
		ELSE
				total=0
		ENDIF

		rem Send result to calculator
		SetRes:(total)
ENDP

rem ----------------------------------------
rem Example : Calculate interest

PROC Interst:
	LOCAL start, term, intr, i 
	LOCAL amount, ret%, show%, elm%

	rem query start capital, term and interest
	term=1.0
	dINIT "Interest calculation"
	dFLOAT start,"Start capital",0.0,100000000.0
	dFLOAT term ,"Term [Years]",1.0,500.0
	dFLOAT intr ,"Interest [%]",0.0,100.0
	LOCK ON
	ret%=DIALOG
	LOCK OFF

	rem rounded years
	term=INTF(term)
	IF ret%
		amount=start
		i=1.0
		show%=1

		DO
			rem calculate new amount
			amount=amount+(amount*intr/100)
			amount=int((amount*100)+0.5)
			amount=amount/100
			
			rem send new amount to stat memory
			rem set calculator in LR mode
			rem X=new amount, Y=year number
			elm%=elm%+1
			SetStatX:(elm%,amount)
			SetStatY:(elm%,i)
			
			IF show% OR (NOT show% AND i=term)

				rem show results
				dINIT "Results"
				dFLOAT i,"Year",0.0,9999.0
				dFLOAT amount,"Amount",0.0,100000000.0
				dBUTTONS "Next year",%n,"Last year",%l,"Stop",%s
				LOCK ON
				ret%=DIALOG
				LOCK OFF
				IF ret%=%l
					show%=0
				ENDIF 

			ENDIF
			i=i+1.0
		UNTIL (i=term+1.0) OR (ret%=%s)
		GIPRINT "Year amounts are stored in LR memory !"
	ENDIF

	rem Send result to calculator
	SetRes:(amount)
	
ENDP