Manipulative Tag Cipher

<Copyright © 2013 Mark Veidemanis>
--Manipulative Tag Cipher--

Tags are inside square brackets
Tags are interpreted as individual letters and operations can be performed on them

Tags:
X = Any Letter
Y Z[...] = Variable Substitutes

1) Positive Shift
	Syntax: "X[+Y]"
	Text Alternative: "X[P Y]"
	#Shifts X Y places forwards in the alphabet

	Example:
	"A[+1]" = "AB"
	"A[P5]" = "AF"

2) Negative Shift
	Syntax: "X[-Y]"
	Text Alternative: "X[N Y]"
	#Shifts X Y places backwards in the alphabet

	Example:
	"A[-3]" = "AX"
	"A[N2]" = "AY"

3) Settable Positive Shift
	Syntax: "X[SPS Y Z]"
	#Shifts Y Z places forwards in the alphabet

	Example:
	"A[SPS A 5]" = "AF"
	"A[SPS 2 5]" = "AG"

4) Settable Negative Shift
	Syntax: "X[SNS Y Z]"
	#Shifts Y Z places backwards in the alphabet

	Example:
	"A[SNS R 1]" = "AQ"
	"A[SNS 2 1]" = "AA"

5) Markers
	#Markers define a specific point in the alphabet or the distance forwards or backwards from the specified point

	A) Center
		Syntax: "[C]"
		#The center of the alphabet, this is 'M'

	B) Start
		Syntax: "[S]" Optional Parameter: "[S + X]"
		#The start of the alphabet
		#Parameter: Count X letters forwards from the start of the alphabet

	C) End
		Syntax: "[E]" Optional Parameter: "[E + X]"
		#The end of the alphabet
		#Parameter: Count X letters backwards from the end of the alphabet

6) Indexes
	Syntax: "[I-X]", "[I+X]", "[--]", "[++]"
	#Skips X places forwards or backwards + or - respectively
	#Can be used as raw signs, the number of signs determines the number of places skipped forwards or backwards depending on the sign
	#Maximum identical signs that can be together is 3

	Example:
	"D[+3] [++] [SPS 3 2][+1]" = "DGFEF"

7) Positive Binary Counter
	Syntax: "X[B+ Y]"
	#Complex: Counts forwards in the alphabet by binary digits
	#See Binary Reference
	Example:
	"A[B+ 10000]" = "AB"

8) Negative Binary Counter
	Syntax: "X[B- Y]"
	#Complex: Counts backwards in the alphabet by binary digits
	#See Binary Reference
	Example:
	"R[B- 10100]" = "RM"

9) Invert Tag
	Syntax: "<I></I>"
	#Inverts all text betweek the tags
	Example:
	"<I> [SPS A 5][+1]</I>" = "GF"

--References--

Binary
	00000 is 0
	1, 2, 4, 8, 16
	01100 is 6
	01011 is 26
	#Maximum digits is 5 because more would allow greater numbers that 26, greater numbers can be used to 'wrap' around the alphabet but are not recommended
	#Any number can be substituted with the corresponding binary string.