regex.inc is a regex parser written in rgbasm. Not assembly, but the macro language. Its primary use is picking apart the arguments to complex macros, but feel free to get creative.
Here's an example (you can test this by running ./run.sh):
include "regex.inc"
; converts a 0-100 percentage to 0-255 if a % sign is present
macro convert_percent ; value[%]
regex "([^%]+)(%?)", "\1", value, percent
if strlen("{percent}")
def result = result * 255 / 100
endc
println "\1 becomes {d:result}"
purge result, value, percent
endm
This is simpler than the built-in solution:
include "regex.inc"
; converts a 0-100 percentage to 0-255 if a % sign is present
macro convert_percent ; value[%]
def percent = strin("\1", "%")
if percent
def value equs strsub("\1", 1, percent - 1)
def result = value * 255 / 100
else
def result = \1
endc
println "\1 becomes {d:result}"
purge result, value, percent
endm
It's also cooler. Regexes are cool.
This can be used to write some pretty silly macros. Like this:
macro jump_if ; a <op> <value>, dest
regex "a? *([=<>]+) *(.+)", "\1", op, value
println "cp {value}"
if !STRCMP("{op}", "==")
jr z, \2
elif !STRCMP("{op}", "!=")
jr nz, \2
elif !STRCMP("{op}", "<")
jr c, \2
elif !STRCMP("{op}", ">=")
jr nc, \2
elif !STRCMP("{op}", "<=")
jr z, \2
jr c, \2
elif !STRCMP("{op}", ">")
jr z, :+
jr nc, \2
:
else
fail "invalid jump_if comparison: {op}"
endc
endm
jump_if a == 100, .where