[bb] Parser Function by add [ 1+ years ago ]

BlitzBot · June 29, 2017, 00:28:42

Title : Parser Function
Author : add
Posted : 1+ years ago

Description : The parser function breaks up a string into words and numbers using delimiter characters.
e.g. "17,2039,84.9" can be broken into three numbers using the delimiter ",".
The function returns the number of elements found, the elements are return in a TYPE which has to be delared in your main code.
Any character can be used as a delimiter but there are some sensible conventions to use.
ie , space ; [] ()
avoid using "." becuase 5.6 would return 5 and 6 which is ok if that is what you want!
avoid using "e" beacuse 5e6 would return 5 and 6 rather than 5000000 again it depends on how you want the parser to work.

The parser can handle some quite complex strings and by using the blitz 'replace$' function delimiter characters can be extended to multiple characters.

The val function is included in the parser but can also be used seperatly.
The val function can equate negative numbers, fractions and exponents.

Code :

Code (blitzbasic) Select

; PARSER AND VAL FUNCTION
;==========================
;by adam barton V1.0
;
;bugs and wish list to add3d@talk21.com
;
;check the example For demostration of how it works!





Function parse(in$,t$) 
; parser functions to break up strings into words and numbers
; returns the number of elements
; fills the type back with the words,integers,and floats
; 
Local rc=0
Local sp=0
Local p
Local q
For back.parsereturn=Each parsereturn ; empty old data
	Delete back
Next
in$=in$+"X"
While Len(in$)>0
	nx=Len(in$)
	For q=1 To Len(t$)
		p=Instr(in$,Mid$(t$,q,sp+1))
		If p<>0 And p<nx Then nx=p
	Next
	r$=Left$(in$,nx-1)
	If r$<>"" Then 
		rc=rc+1
		back.parsereturn=New parsereturn
		backword$=r$
		back
um=val(r$)
		backeal=realreturn#
		;back
um=Int(realreturn#)
	End If
	in$=Right$(in$,Len(in$)-nx)
Wend
Return rc
End Function 
;========================================================
Function val(txt$)
; val converts a string to a number
; handles negative,fractions and exponents
; the realvalue is returned in realreturn# DEFINE GLOBALY!!!!
;											Global RealReturn#=0
; the integer is returned
Local d$="" ;the whole number
Local dn
Local f$=""	;the fraction
Local fn#
Local e$=""	;the exponent
Local en#
Local s=0
; This did use an array but it has to be declared outside the function which was a pain
got=0

For q=1 To Len(txt$)
	l$=Mid$(txt$,q,1)
	If l$="e" And (Len(d$)+Len(f$))>0 Then got=2
	If l$="." Then If got=0 Then got=1 Else got=3
	If got<>3 And Instr("-1234567890",l,1)>0 Then
		If got=0 Then d$=d$+l$
		If got=1 Then f$=f$+l$
		If got=2 Then e$=e$+l$
	End If
Next
dn=vint(d$):s=Sgn(dn):dn=Abs(dn):If s=0 Then s=1
fn#=(vint(f$))/(10.0^Len(f$))
en#=10^vint(e$)
realreturn#=s*((dn+fn#)*en#)
Return (Int(realreturn#))
End Function
;========================================================
Function vint(txt$)
; vint converts a string of digits into a signed integer
vi=0
If Left$(txt$,1)="-" Then s=-1:txt$=Right$(txt$,Len(txt$)-1) Else s=1
For q=1 To Len(txt$)
	v=Asc(Mid$(txt$,q,1))-48
	vi=vi*10+v
Next
vi=vi*s
Return vi
End Function

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[bb] Parser Function by add [ 1+ years ago ]

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